Roundup Weather Records (USC00247214)

Record envelope, standing records and threshold days for Roundup (USC00247214), Montana, United States, with 106 years of record.

Key Facts for Roundup

Roundup (USC00247214) is a weather station in Montana, United States at 46.44 latitude and -108.53 longitude, 975 m (3,200 ft) above sea level.
The station reports from 1914 to 2019, 106 years of record.
1,464 records set at Roundup still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Roundup tied an all-time record snow depth of 45.7 cm (18.0 in) on 28 February 2019.

About the Station

Location: Montana, United States, 46.44 latitude, -108.53 longitude.
Elevation: 975 m (3,200 ft).
Period of record: 1914 to 2019, 106 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at Roundup. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.

Daily record high and record low at Roundup, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	21.1 C (70.0 F)	-40.6 C (-41.1 F)	n/a	n/a
Feb	23.9 C (75.0 F)	-46.7 C (-52.1 F)	n/a	n/a
Mar	27.8 C (82.0 F)	-36.1 C (-33.0 F)	n/a	n/a
Apr	32.8 C (91.0 F)	-22.8 C (-9.0 F)	n/a	n/a
May	37.8 C (100.0 F)	-12.2 C (10.0 F)	n/a	n/a
Jun	41.1 C (106.0 F)	-0.6 C (30.9 F)	n/a	n/a
Jul	43.9 C (111.0 F)	2.2 C (36.0 F)	n/a	n/a
Aug	42.2 C (108.0 F)	-1.1 C (30.0 F)	n/a	n/a
Sep	38.9 C (102.0 F)	-9.4 C (15.1 F)	n/a	n/a
Oct	35.0 C (95.0 F)	-23.3 C (-9.9 F)	n/a	n/a
Nov	25.0 C (77.0 F)	-37.8 C (-36.0 F)	n/a	n/a
Dec	21.1 C (70.0 F)	-42.2 C (-44.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Roundup still stand. 1914 holds the most, with 48.

Standing records at Roundup by the year they were set
Year set	Standing records
1914	48
1915	5
1916	27
1917	26
1918	12
1919	41
1920	10
1921	34
1922	18
1923	2
1930	20
1931	23
1932	24
1933	15
1934	31
1935	19
1936	32
1937	10
1938	10
1939	15
1940	13
1941	8
1942	13
1943	28
1944	10
1945	9
1946	9
1947	14
1948	11
1949	22
1950	32
1951	21
1952	6
1953	10
1954	31
1955	17
1956	13
1957	9
1958	11
1959	12
1960	18
1961	12
1962	18
1963	14
1964	1
1965	22
1966	12
1967	9
1968	17
1969	21
1970	11
1971	10
1972	24
1973	13
1974	12
1975	6
1976	13
1977	11
1978	10
1979	6
1980	16
1981	10
1982	10
1983	19
1984	12
1985	24
1986	13
1987	16
1988	17
1989	15
1990	5
1991	11
1992	15
1993	14
1994	11
1995	12
1996	13
1997	11
1998	5
1999	11
2000	10
2001	5
2002	18
2003	19
2004	11
2005	7
2006	4
2007	15
2008	18
2009	8
2010	7
2011	5
2012	13
2013	11
2014	11
2015	18
2016	10
2017	14
2018	17
2019	2

All-Time Record Progression

9 new records

9 all-time records were set at Roundup between 21 July 1955 and 23 August 2014. Each dot is a new record.

When Roundup set new all-time records
Date	Kind	Detail
1955-07-21	Record daily precipitation	Record daily precipitation 59.7 mm (2.4 in)
1961-08-05	Record high maximum temperature	Record high maximum temperature 42.2 C (108.0 F)
1967-06-07	Record daily precipitation	Record daily precipitation 63.5 mm (2.5 in)
1968-06-09	Record daily precipitation	Record daily precipitation 65.5 mm (2.6 in)
1975-10-22	Record daily precipitation	Record daily precipitation 76.2 mm (3.0 in)
1980-07-23	Record high maximum temperature	Record high maximum temperature 42.8 C (109.0 F)
2002-07-13	Record high maximum temperature	Record high maximum temperature 43.3 C (109.9 F)
2002-07-14	Record high maximum temperature	Record high maximum temperature 43.9 C (111.0 F)
2014-08-23	Record daily precipitation	Record daily precipitation 85.9 mm (3.4 in)

Wettest Day of Each Month

Aug: 85.9 mm (3.4 in)

The wettest day on record for each calendar month at Roundup. The most was 85.9 mm (3.4 in) on 23 August 2014.

Record daily precipitation for each month at Roundup
Month	Record daily precipitation (mm)	Date
Jan	19.1 mm (0.8 in)	25 January 1918
Feb	18.5 mm (0.7 in)	2 February 1966
Mar	43.9 mm (1.7 in)	2 March 1967
Apr	50.0 mm (2.0 in)	15 April 1930
May	58.4 mm (2.3 in)	12 May 1942
Jun	65.5 mm (2.6 in)	9 June 1968
Jul	59.7 mm (2.4 in)	21 July 1955
Aug	85.9 mm (3.4 in)	23 August 2014
Sep	48.5 mm (1.9 in)	12 September 1978
Oct	76.2 mm (3.0 in)	22 October 1975
Nov	16.3 mm (0.6 in)	1 November 1957
Dec	76.2 mm (3.0 in)	10 December 2000

Period of Record Coverage

1914 to 2019

100 years of record at Roundup, 1914 to 2019. 31 years have data for under 90 percent of days and are left out of rankings: 1914, 1915, 1917, 1918, 1920, 1921, 1923, 1936 and others.

Days with data per year at Roundup
Year	Days with data	Share of year	Complete
1914	202	55%	No
1915	177	48%	No
1916	343	94%	Yes
1917	322	88%	No
1918	177	48%	No
1919	356	98%	Yes
1920	294	80%	No
1921	324	89%	No
1922	361	99%	Yes
1923	30	8%	No
1930	364	100%	Yes
1931	365	100%	Yes
1932	366	100%	Yes
1933	363	99%	Yes
1934	365	100%	Yes
1935	365	100%	Yes
1936	271	74%	No
1937	334	92%	Yes
1938	364	100%	Yes
1939	364	100%	Yes
1940	305	83%	No
1941	331	91%	Yes
1942	360	99%	Yes
1943	361	99%	Yes
1944	364	99%	Yes
1945	334	92%	Yes
1946	365	100%	Yes
1947	364	100%	Yes
1948	363	99%	Yes
1949	365	100%	Yes
1950	365	100%	Yes
1951	365	100%	Yes
1952	366	100%	Yes
1953	365	100%	Yes
1954	364	100%	Yes
1955	363	99%	Yes
1956	366	100%	Yes
1957	365	100%	Yes
1958	363	99%	Yes
1959	365	100%	Yes
1960	365	100%	Yes
1961	360	99%	Yes
1962	361	99%	Yes
1963	364	100%	Yes
1964	365	100%	Yes
1965	365	100%	Yes
1966	364	100%	Yes
1967	364	100%	Yes
1968	363	99%	Yes
1969	363	99%	Yes
1970	363	99%	Yes
1971	362	99%	Yes
1972	363	99%	Yes
1973	350	96%	Yes
1974	307	84%	No
1975	329	90%	Yes
1976	323	88%	No
1977	344	94%	Yes
1978	323	88%	No
1979	247	68%	No
1980	342	93%	Yes
1981	332	91%	Yes
1982	323	88%	No
1983	316	87%	No
1984	327	89%	No
1985	304	83%	No
1986	301	82%	No
1987	291	80%	No
1988	316	86%	No
1989	295	81%	No
1990	317	87%	No
1991	324	89%	No
1992	321	88%	No
1993	344	94%	Yes
1994	349	96%	Yes
1995	345	95%	Yes
1996	318	87%	No
1997	321	88%	No
1998	348	95%	Yes
1999	349	96%	Yes
2000	319	87%	No
2001	352	96%	Yes
2002	319	87%	No
2003	324	89%	No
2004	335	92%	Yes
2005	359	98%	Yes
2006	359	98%	Yes
2007	362	99%	Yes
2008	359	98%	Yes
2009	363	99%	Yes
2010	362	99%	Yes
2011	364	100%	Yes
2012	365	100%	Yes
2013	365	100%	Yes
2014	364	100%	Yes
2015	364	100%	Yes
2016	360	98%	Yes
2017	365	100%	Yes
2018	283	78%	No
2019	59	16%	No

Latest Records

Latest records at Roundup
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
28 February 2019	Roundup, US	all-time snow depth (Tie)	45.7 cm (18.0 in)	tie	83 years	13 of 100 (Routine)
27 February 2019	Roundup, US	all-time snow depth (Tie)	45.7 cm (18.0 in)	tie	83 years	13 of 100 (Routine)
25 February 2019	Roundup, US	monthly snowfall	43.2 cm (17.0 in)	15.3 cm (6.0 in)	23 years	58 of 100 (Notable)
25 February 2019	Roundup, US	daily low max	-18.3 C (-0.9 F)	0.5 C (0.9 F)	101 years	40 of 100 (Notable)
25 February 2019	Roundup, US	daily snow depth	43.2 cm (17.0 in)	5.1 cm (2.0 in)	83 years	40 of 100 (Notable)
24 February 2019	Roundup, US	daily low max	-17.2 C (1.0 F)	0.5 C (0.9 F)	101 years	40 of 100 (Notable)
16 February 2019	Roundup, US	daily snowfall	7.6 cm (3.0 in)	2.5 cm (1.0 in)	87 years	41 of 100 (Notable)
4 February 2019	Roundup, US	daily rain	10.2 mm (0.4 in)	2.6 mm (0.10 in)	103 years	20 of 100 (Routine)
25 December 2018	Roundup, US	daily rain	7.9 mm (0.31 in)	1.3 mm (0.05 in)	21 years	18 of 100 (Routine)
25 December 2018	Roundup, US	daily snowfall	8.1 cm (3.2 in)	0.5 cm (0.2 in)	21 years	16 of 100 (Routine)
8 November 2018	Roundup, US	daily snowfall	2.5 cm (1.0 in)	2.5 cm (1.0 in)	104 years	20 of 100 (Routine)
30 September 2018	Roundup, US	daily low max	5.0 C (41.0 F)	0.6 C (1.1 F)	64 years	29 of 100 (Routine)
30 September 2018	Roundup, US	daily rain	14.0 mm (0.6 in)	3.6 mm (0.14 in)	40 years	20 of 100 (Routine)
27 August 2018	Roundup, US	daily low max	16.1 C (61.0 F)	2.8 C (5.0 F)	67 years	36 of 100 (Notable)
21 August 2018	Roundup, US	daily low max	14.4 C (57.9 F)	2.8 C (5.0 F)	52 years	31 of 100 (Routine)
20 August 2018	Roundup, US	daily low max	13.3 C (55.9 F)	0.6 C (1.1 F)	53 years	27 of 100 (Routine)
22 June 2018	Roundup, US	daily rain	31.5 mm (1.2 in)	1.0 mm (0.04 in)	4 years	12 of 100 (Routine)
19 June 2018	Roundup, US	daily low max	13.3 C (55.9 F)	4.5 C (8.1 F)	76 years	40 of 100 (Notable)
19 June 2018	Roundup, US	daily rain	23.6 mm (0.9 in)	5.3 mm (0.21 in)	80 years	20 of 100 (Routine)
1 June 2018	Roundup, US	daily rain	42.2 mm (1.7 in)	16.8 mm (0.7 in)	79 years	53 of 100 (Notable)

Climate Trend

71 complete years, 1916 to 2017

One stripe for each of 71 complete years at Roundup, 1916 to 2017. Blue stripes are years cooler than the station's own mean of 8.6 C (47.4 F); red stripes are warmer. The coolest year was 1916, at 4.8 C (40.6 F), and the warmest was 2012, at 10.4 C (50.7 F). The strongest colour marks a difference of 3.8 C (6.8 F).

Annual mean temperature at Roundup as warming stripes, 1916 to 2017
Year	Annual mean temperature	Difference from the station mean
1916	4.8 C	-3.78 C
1919	7.6 C	-1.01 C
1922	6.8 C	-1.75 C
1930	8.7 C	+0.08 C
1931	9.8 C	+1.17 C
1932	7.6 C	-0.97 C
1933	8.2 C	-0.43 C
1934	9.8 C	+1.22 C
1935	7.3 C	-1.33 C
1938	8.7 C	+0.13 C
1939	9.3 C	+0.75 C
1942	8.3 C	-0.28 C
1943	9.1 C	+0.55 C
1944	9.1 C	+0.51 C
1946	9.3 C	+0.68 C
1947	8.7 C	+0.16 C
1948	8.4 C	-0.20 C
1949	7.9 C	-0.68 C
1950	6.9 C	-1.70 C
1951	6.2 C	-2.38 C
1952	8.8 C	+0.19 C
1953	10.0 C	+1.39 C
1954	8.8 C	+0.25 C
1955	7.3 C	-1.25 C
1956	8.4 C	-0.15 C
1957	7.8 C	-0.74 C
1958	8.9 C	+0.36 C
1959	7.7 C	-0.91 C
1960	8.4 C	-0.16 C
1961	9.4 C	+0.83 C
1962	8.0 C	-0.62 C
1963	7.6 C	-0.99 C
1964	8.5 C	-0.06 C
1965	8.0 C	-0.58 C
1966	8.9 C	+0.27 C
1967	8.9 C	+0.34 C
1968	8.5 C	-0.09 C
1969	7.8 C	-0.74 C
1970	8.6 C	-0.01 C
1972	7.3 C	-1.30 C
1977	8.8 C	+0.25 C
1980	9.2 C	+0.62 C
1982	7.4 C	-1.18 C
1984	9.0 C	+0.44 C
1985	7.1 C	-1.45 C
1986	9.2 C	+0.60 C
1987	9.9 C	+1.30 C
1988	9.7 C	+1.10 C
1989	7.7 C	-0.87 C
1991	9.1 C	+0.49 C
1992	9.4 C	+0.79 C
1993	7.2 C	-1.36 C
1994	9.0 C	+0.43 C
1995	8.5 C	-0.12 C
1998	9.3 C	+0.74 C
1999	9.8 C	+1.21 C
2001	9.7 C	+1.14 C
2004	9.4 C	+0.79 C
2005	9.4 C	+0.84 C
2006	10.2 C	+1.62 C
2007	10.1 C	+1.47 C
2008	8.5 C	-0.12 C
2009	8.3 C	-0.28 C
2010	8.6 C	-0.03 C
2011	8.8 C	+0.24 C
2012	10.4 C	+1.81 C
2013	9.2 C	+0.64 C
2014	8.6 C	+0.03 C
2015	10.2 C	+1.66 C
2016	9.1 C	+0.52 C
2017	8.2 C	-0.35 C

The annual mean temperature here has risen by 0.2 C (0.1 to 0.2) per decade over 1916 to 2017. In Fahrenheit: 0.3 F (0.1 to 0.4) per decade. The slope is a straight line fitted to 71 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Roundup
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.2 C (0.1 to 0.2) per decade	0.3 F (0.1 to 0.4) per decade	1916 to 2017	71	Rise
Mean daily maximum	0.14 C (0.04 to 0.24) per decade	0.3 F (0.1 to 0.4) per decade	1916 to 2017	71	Rise
Mean daily minimum	0.2 C (0.1 to 0.2) per decade	0.3 F (0.2 to 0.4) per decade	1916 to 2017	71	Rise

A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.

Extremes by Year

1914 to 2019

Yearly extremes at Roundup: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	43.9 C (111.0 F)	2002	38.9 C (102.0 F)	100
Coldest night (TNn)	-46.7 C (-52.1 F)	1936	-33.3 C (-27.9 F)	100
Wettest day (Rx1day)	85.9 mm (3.4 in)	2014	29.7 mm (1.2 in)	100
Wettest five days (Rx5day)	158.6 mm (6.2 in)	2014	47.9 mm (1.9 in)	100
Longest dry spell (CDD)	95 days	1941	40 days	100

Hottest day (TXx)

The hottest day of the year at Roundup, 1914 to 2019. The record is 43.9 C (111.0 F) in 2002, marked on the chart; the median year is 38.9 C (102.0 F).

Hottest day (TXx) at Roundup by year
Year	Hottest day (TXx)
1914	38.9 C (102.0 F)
1915	35.6 C (96.1 F)
1916	37.2 C (99.0 F)
1917	36.7 C (98.1 F)
1918	31.7 C (89.1 F)
1919	40.6 C (105.1 F)
1920	35.0 C (95.0 F)
1921	38.3 C (100.9 F)
1922	36.1 C (97.0 F)
1923	21.1 C (70.0 F)
1930	40.0 C (104.0 F)
1931	41.1 C (106.0 F)
1932	37.8 C (100.0 F)
1933	41.7 C (107.1 F)
1934	41.1 C (106.0 F)
1935	40.6 C (105.1 F)
1936	36.7 C (98.1 F)
1937	40.6 C (105.1 F)
1938	36.7 C (98.1 F)
1939	40.0 C (104.0 F)
1940	40.0 C (104.0 F)
1941	41.1 C (106.0 F)
1942	39.4 C (102.9 F)
1943	41.1 C (106.0 F)
1944	38.3 C (100.9 F)
1945	38.3 C (100.9 F)
1946	37.8 C (100.0 F)
1947	38.9 C (102.0 F)
1948	38.3 C (100.9 F)
1949	40.6 C (105.1 F)
1950	38.9 C (102.0 F)
1951	39.4 C (102.9 F)
1952	37.2 C (99.0 F)
1953	40.0 C (104.0 F)
1954	37.8 C (100.0 F)
1955	40.6 C (105.1 F)
1956	40.6 C (105.1 F)
1957	38.9 C (102.0 F)
1958	37.2 C (99.0 F)
1959	40.0 C (104.0 F)
1960	40.6 C (105.1 F)
1961	42.2 C (108.0 F)
1962	36.7 C (98.1 F)
1963	38.9 C (102.0 F)
1964	38.9 C (102.0 F)
1965	38.9 C (102.0 F)
1966	41.1 C (106.0 F)
1967	37.8 C (100.0 F)
1968	35.6 C (96.1 F)
1969	40.0 C (104.0 F)
1970	38.9 C (102.0 F)
1971	40.0 C (104.0 F)
1972	38.3 C (100.9 F)
1973	40.0 C (104.0 F)
1974	38.3 C (100.9 F)
1975	36.1 C (97.0 F)
1976	38.9 C (102.0 F)
1977	38.3 C (100.9 F)
1978	37.2 C (99.0 F)
1979	37.8 C (100.0 F)
1980	42.8 C (109.0 F)
1981	37.8 C (100.0 F)
1982	36.7 C (98.1 F)
1983	41.1 C (106.0 F)
1984	40.6 C (105.1 F)
1985	40.0 C (104.0 F)
1986	36.7 C (98.1 F)
1987	35.6 C (96.1 F)
1988	38.3 C (100.9 F)
1989	38.3 C (100.9 F)
1990	37.2 C (99.0 F)
1991	36.7 C (98.1 F)
1992	35.6 C (96.1 F)
1993	33.9 C (93.0 F)
1994	35.6 C (96.1 F)
1995	38.9 C (102.0 F)
1996	37.2 C (99.0 F)
1997	35.6 C (96.1 F)
1998	37.8 C (100.0 F)
1999	38.3 C (100.9 F)
2000	38.9 C (102.0 F)
2001	38.3 C (100.9 F)
2002	43.9 C (111.0 F)
2003	42.2 C (108.0 F)
2004	40.6 C (105.1 F)
2005	41.1 C (106.0 F)
2006	40.6 C (105.1 F)
2007	42.2 C (108.0 F)
2008	40.6 C (105.1 F)
2009	37.8 C (100.0 F)
2010	38.9 C (102.0 F)
2011	38.9 C (102.0 F)
2012	40.0 C (104.0 F)
2013	37.8 C (100.0 F)
2014	38.3 C (100.9 F)
2015	40.6 C (105.1 F)
2016	38.9 C (102.0 F)
2017	41.1 C (106.0 F)
2018	36.1 C (97.0 F)
2019	13.9 C (57.0 F)

Coldest night (TNn)

The coldest night of the year at Roundup, 1914 to 2019. The record is -46.7 C (-52.1 F) in 1936, marked on the chart; the median year is -33.3 C (-27.9 F).

Coldest night (TNn) at Roundup by year
Year	Coldest night (TNn)
1914	-26.7 C (-16.1 F)
1915	-27.8 C (-18.0 F)
1916	-38.3 C (-36.9 F)
1917	-39.4 C (-38.9 F)
1918	-39.4 C (-38.9 F)
1919	-41.7 C (-43.1 F)
1920	-35.0 C (-31.0 F)
1921	-31.1 C (-24.0 F)
1922	-34.4 C (-29.9 F)
1923	-29.4 C (-20.9 F)
1930	-37.8 C (-36.0 F)
1931	-20.6 C (-5.1 F)
1932	-36.1 C (-33.0 F)
1933	-37.8 C (-36.0 F)
1934	-26.1 C (-15.0 F)
1935	-37.2 C (-35.0 F)
1936	-46.7 C (-52.1 F)
1937	-33.3 C (-27.9 F)
1938	-34.4 C (-29.9 F)
1939	-36.1 C (-33.0 F)
1940	-33.3 C (-27.9 F)
1941	-27.2 C (-17.0 F)
1942	-35.6 C (-32.1 F)
1943	-33.3 C (-27.9 F)
1944	-27.8 C (-18.0 F)
1945	-28.3 C (-18.9 F)
1946	-27.2 C (-17.0 F)
1947	-32.2 C (-26.0 F)
1948	-29.4 C (-20.9 F)
1949	-35.6 C (-32.1 F)
1950	-35.0 C (-31.0 F)
1951	-34.4 C (-29.9 F)
1952	-35.6 C (-32.1 F)
1953	-21.7 C (-7.1 F)
1954	-39.4 C (-38.9 F)
1955	-31.7 C (-25.1 F)
1956	-33.3 C (-27.9 F)
1957	-40.6 C (-41.1 F)
1958	-23.3 C (-9.9 F)
1959	-37.8 C (-36.0 F)
1960	-30.0 C (-22.0 F)
1961	-28.3 C (-18.9 F)
1962	-35.0 C (-31.0 F)
1963	-36.1 C (-33.0 F)
1964	-35.0 C (-31.0 F)
1965	-30.0 C (-22.0 F)
1966	-30.6 C (-23.1 F)
1967	-30.6 C (-23.1 F)
1968	-36.1 C (-33.0 F)
1969	-40.6 C (-41.1 F)
1970	-26.7 C (-16.1 F)
1971	-30.0 C (-22.0 F)
1972	-37.2 C (-35.0 F)
1973	-35.0 C (-31.0 F)
1974	-32.8 C (-27.0 F)
1975	-33.9 C (-29.0 F)
1976	-29.4 C (-20.9 F)
1977	-31.1 C (-24.0 F)
1978	-37.2 C (-35.0 F)
1979	-34.4 C (-29.9 F)
1980	-34.4 C (-29.9 F)
1981	-30.0 C (-22.0 F)
1982	-34.4 C (-29.9 F)
1983	-42.2 C (-44.0 F)
1984	-31.7 C (-25.1 F)
1985	-33.3 C (-27.9 F)
1986	-27.8 C (-18.0 F)
1987	-19.4 C (-2.9 F)
1988	-28.3 C (-18.9 F)
1989	-37.8 C (-36.0 F)
1990	-35.6 C (-32.1 F)
1991	-25.6 C (-14.1 F)
1992	-30.6 C (-23.1 F)
1993	-30.6 C (-23.1 F)
1994	-32.2 C (-26.0 F)
1995	-28.3 C (-18.9 F)
1996	-40.6 C (-41.1 F)
1997	-36.1 C (-33.0 F)
1998	-35.6 C (-32.1 F)
1999	-22.2 C (-8.0 F)
2000	-27.8 C (-18.0 F)
2001	-23.9 C (-11.0 F)
2002	-26.7 C (-16.1 F)
2003	-31.1 C (-24.0 F)
2004	-36.7 C (-34.1 F)
2005	-35.0 C (-31.0 F)
2006	-29.4 C (-20.9 F)
2007	-26.7 C (-16.1 F)
2008	-32.2 C (-26.0 F)
2009	-30.6 C (-23.1 F)
2010	-35.6 C (-32.1 F)
2011	-33.3 C (-27.9 F)
2012	-23.9 C (-11.0 F)
2013	-31.1 C (-24.0 F)
2014	-36.1 C (-33.0 F)
2015	-29.4 C (-20.9 F)
2016	-35.6 C (-32.1 F)
2017	-31.7 C (-25.1 F)
2018	-31.7 C (-25.1 F)
2019	-33.9 C (-29.0 F)

Wettest day (Rx1day)

The wettest day of the year at Roundup, 1914 to 2019. The record is 85.9 mm (3.4 in) in 2014, marked on the chart; the median year is 29.7 mm (1.2 in).

Wettest day (Rx1day) at Roundup by year
Year	Wettest day (Rx1day)
1914	35.1 mm (1.4 in)
1915	30.5 mm (1.2 in)
1916	25.4 mm (1.0 in)
1917	44.5 mm (1.8 in)
1918	19.1 mm (0.8 in)
1919	36.6 mm (1.4 in)
1920	29.7 mm (1.2 in)
1921	26.7 mm (1.1 in)
1922	39.4 mm (1.6 in)
1923	2.5 mm (0.10 in)
1930	50.0 mm (2.0 in)
1931	15.2 mm (0.6 in)
1932	28.7 mm (1.1 in)
1933	13.2 mm (0.5 in)
1934	32.8 mm (1.3 in)
1935	20.8 mm (0.8 in)
1936	16.8 mm (0.7 in)
1937	36.8 mm (1.4 in)
1938	38.9 mm (1.5 in)
1939	27.9 mm (1.1 in)
1940	35.3 mm (1.4 in)
1941	22.9 mm (0.9 in)
1942	58.4 mm (2.3 in)
1943	25.4 mm (1.0 in)
1944	33.0 mm (1.3 in)
1945	20.1 mm (0.8 in)
1946	33.5 mm (1.3 in)
1947	33.0 mm (1.3 in)
1948	20.6 mm (0.8 in)
1949	29.2 mm (1.1 in)
1950	17.0 mm (0.7 in)
1951	28.2 mm (1.1 in)
1952	20.3 mm (0.8 in)
1953	27.4 mm (1.1 in)
1954	20.6 mm (0.8 in)
1955	59.7 mm (2.4 in)
1956	29.7 mm (1.2 in)
1957	31.2 mm (1.2 in)
1958	19.6 mm (0.8 in)
1959	36.1 mm (1.4 in)
1960	23.6 mm (0.9 in)
1961	30.0 mm (1.2 in)
1962	33.8 mm (1.3 in)
1963	15.5 mm (0.6 in)
1964	56.6 mm (2.2 in)
1965	37.8 mm (1.5 in)
1966	18.5 mm (0.7 in)
1967	63.5 mm (2.5 in)
1968	65.5 mm (2.6 in)
1969	39.6 mm (1.6 in)
1970	29.2 mm (1.1 in)
1971	30.2 mm (1.2 in)
1972	41.1 mm (1.6 in)
1973	26.2 mm (1.0 in)
1974	29.0 mm (1.1 in)
1975	76.2 mm (3.0 in)
1976	25.4 mm (1.0 in)
1977	22.9 mm (0.9 in)
1978	48.5 mm (1.9 in)
1979	19.3 mm (0.8 in)
1980	28.7 mm (1.1 in)
1981	34.3 mm (1.4 in)
1982	37.3 mm (1.5 in)
1983	29.2 mm (1.1 in)
1984	18.8 mm (0.7 in)
1985	26.7 mm (1.1 in)
1986	42.9 mm (1.7 in)
1987	50.5 mm (2.0 in)
1988	28.2 mm (1.1 in)
1989	20.3 mm (0.8 in)
1990	39.9 mm (1.6 in)
1991	28.2 mm (1.1 in)
1992	41.9 mm (1.6 in)
1993	43.4 mm (1.7 in)
1994	34.3 mm (1.4 in)
1995	48.3 mm (1.9 in)
1996	25.1 mm (1.0 in)
1997	34.5 mm (1.4 in)
1998	37.6 mm (1.5 in)
1999	20.6 mm (0.8 in)
2000	76.2 mm (3.0 in)
2001	27.9 mm (1.1 in)
2002	21.1 mm (0.8 in)
2003	18.5 mm (0.7 in)
2004	25.4 mm (1.0 in)
2005	39.1 mm (1.5 in)
2006	20.6 mm (0.8 in)
2007	52.6 mm (2.1 in)
2008	30.2 mm (1.2 in)
2009	43.2 mm (1.7 in)
2010	31.5 mm (1.2 in)
2011	26.7 mm (1.1 in)
2012	23.4 mm (0.9 in)
2013	31.2 mm (1.2 in)
2014	85.9 mm (3.4 in)
2015	15.7 mm (0.6 in)
2016	37.1 mm (1.5 in)
2017	24.4 mm (1.0 in)
2018	42.2 mm (1.7 in)
2019	10.2 mm (0.4 in)

Wettest five days (Rx5day)

The wettest five days of the year at Roundup, 1914 to 2019. The record is 158.6 mm (6.2 in) in 2014, marked on the chart; the median year is 47.9 mm (1.9 in).

Wettest five days (Rx5day) at Roundup by year
Year	Wettest five days (Rx5day)
1914	36.4 mm (1.4 in)
1915	49.6 mm (2.0 in)
1916	51.5 mm (2.0 in)
1917	56.7 mm (2.2 in)
1918	28.8 mm (1.1 in)
1919	36.6 mm (1.4 in)
1920	66.2 mm (2.6 in)
1921	51.1 mm (2.0 in)
1922	43.5 mm (1.7 in)
1923	3.0 mm (0.12 in)
1930	69.1 mm (2.7 in)
1931	25.6 mm (1.0 in)
1932	62.2 mm (2.4 in)
1933	47.7 mm (1.9 in)
1934	67.6 mm (2.7 in)
1935	23.6 mm (0.9 in)
1936	22.3 mm (0.9 in)
1937	49.5 mm (1.9 in)
1938	80.6 mm (3.2 in)
1939	68.8 mm (2.7 in)
1940	48.5 mm (1.9 in)
1941	35.6 mm (1.4 in)
1942	80.0 mm (3.1 in)
1943	67.6 mm (2.7 in)
1944	58.9 mm (2.3 in)
1945	38.4 mm (1.5 in)
1946	40.4 mm (1.6 in)
1947	41.9 mm (1.6 in)
1948	29.7 mm (1.2 in)
1949	34.0 mm (1.3 in)
1950	32.5 mm (1.3 in)
1951	53.9 mm (2.1 in)
1952	22.8 mm (0.9 in)
1953	55.5 mm (2.2 in)
1954	30.6 mm (1.2 in)
1955	63.8 mm (2.5 in)
1956	47.0 mm (1.9 in)
1957	49.2 mm (1.9 in)
1958	45.0 mm (1.8 in)
1959	40.1 mm (1.6 in)
1960	30.7 mm (1.2 in)
1961	49.2 mm (1.9 in)
1962	50.3 mm (2.0 in)
1963	24.4 mm (1.0 in)
1964	72.9 mm (2.9 in)
1965	42.4 mm (1.7 in)
1966	19.0 mm (0.7 in)
1967	106.7 mm (4.2 in)
1968	100.5 mm (4.0 in)
1969	91.2 mm (3.6 in)
1970	45.2 mm (1.8 in)
1971	44.9 mm (1.8 in)
1972	58.1 mm (2.3 in)
1973	36.9 mm (1.5 in)
1974	35.1 mm (1.4 in)
1975	99.9 mm (3.9 in)
1976	48.1 mm (1.9 in)
1977	39.7 mm (1.6 in)
1978	68.3 mm (2.7 in)
1979	27.2 mm (1.1 in)
1980	36.1 mm (1.4 in)
1981	55.5 mm (2.2 in)
1982	65.0 mm (2.6 in)
1983	36.8 mm (1.4 in)
1984	30.3 mm (1.2 in)
1985	30.5 mm (1.2 in)
1986	42.9 mm (1.7 in)
1987	70.6 mm (2.8 in)
1988	33.3 mm (1.3 in)
1989	34.3 mm (1.4 in)
1990	66.8 mm (2.6 in)
1991	71.0 mm (2.8 in)
1992	84.6 mm (3.3 in)
1993	69.4 mm (2.7 in)
1994	55.4 mm (2.2 in)
1995	70.7 mm (2.8 in)
1996	42.1 mm (1.7 in)
1997	60.7 mm (2.4 in)
1998	45.0 mm (1.8 in)
1999	43.0 mm (1.7 in)
2000	101.6 mm (4.0 in)
2001	49.5 mm (1.9 in)
2002	28.8 mm (1.1 in)
2003	38.3 mm (1.5 in)
2004	43.0 mm (1.7 in)
2005	51.8 mm (2.0 in)
2006	38.1 mm (1.5 in)
2007	85.4 mm (3.4 in)
2008	95.9 mm (3.8 in)
2009	52.0 mm (2.0 in)
2010	37.6 mm (1.5 in)
2011	89.8 mm (3.5 in)
2012	37.9 mm (1.5 in)
2013	79.8 mm (3.1 in)
2014	158.6 mm (6.2 in)
2015	28.1 mm (1.1 in)
2016	47.5 mm (1.9 in)
2017	52.3 mm (2.1 in)
2018	79.2 mm (3.1 in)
2019	10.2 mm (0.4 in)

Longest dry spell (CDD)

The longest dry spell of the year at Roundup, 1914 to 2019. The record is 95 days in 1941, marked on the chart; the median year is 40 days.

Longest dry spell (CDD) at Roundup by year
Year	Longest dry spell (CDD)
1914	34 days
1915	22 days
1916	54 days
1917	33 days
1918	40 days
1919	34 days
1920	31 days
1921	47 days
1922	31 days
1923	22 days
1930	41 days
1931	66 days
1932	46 days
1933	53 days
1934	80 days
1935	43 days
1936	33 days
1937	40 days
1938	50 days
1939	42 days
1940	55 days
1941	95 days
1942	72 days
1943	56 days
1944	36 days
1945	30 days
1946	46 days
1947	45 days
1948	53 days
1949	50 days
1950	30 days
1951	28 days
1952	46 days
1953	29 days
1954	67 days
1955	42 days
1956	27 days
1957	60 days
1958	38 days
1959	57 days
1960	50 days
1961	36 days
1962	27 days
1963	35 days
1964	39 days
1965	41 days
1966	36 days
1967	43 days
1968	32 days
1969	35 days
1970	29 days
1971	49 days
1972	35 days
1973	31 days
1974	60 days
1975	28 days
1976	52 days
1977	58 days
1978	39 days
1979	40 days
1980	52 days
1981	75 days
1982	32 days
1983	61 days
1984	40 days
1985	38 days
1986	49 days
1987	53 days
1988	27 days
1989	19 days
1990	40 days
1991	40 days
1992	65 days
1993	45 days
1994	40 days
1995	29 days
1996	39 days
1997	38 days
1998	34 days
1999	47 days
2000	25 days
2001	38 days
2002	27 days
2003	39 days
2004	61 days
2005	34 days
2006	44 days
2007	41 days
2008	27 days
2009	28 days
2010	51 days
2011	41 days
2012	48 days
2013	34 days
2014	26 days
2015	29 days
2016	59 days
2017	39 days
2018	23 days
2019	16 days

Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.

Frost Dates and Growing Season

71 years with a frost

Across 71 years with a frost, the median last spring frost at Roundup falls on 18 May and the median first autumn frost on 21 September, which leaves a median of 125 days between them.

In 1980 to 2017 the median growing season was 127 days. That is 3 days more than in 1916 to 1961.

Fitted over all years, the growing season changes by +0.6 days per decade at this station.

Frost dates and growing season at Roundup
Measure	Median, all years	Earliest period (1916 to 1961)	Recent period (1980 to 2017)	Recent against earliest	Fitted trend
Last spring frost	18 May	20 May	14 May	6 days earlier	-0.1 days per decade
First autumn frost	21 September	21 September	21 September	no change	+0.6 days per decade
Growing days	125 days	124 days	127 days	3 days more	+0.6 days per decade

A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.

Rainfall Return Levels

86 years, 1916 to 2017

A day with at least 30.0 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 82.2 mm (3.2 in) of rain is expected about once in 100 years.

Rainfall return levels at Roundup: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	30.0 mm (1.2 in)
5 years	41.5 mm (1.6 in)
10 years	50.1 mm (2.0 in)
25 years	62.0 mm (2.4 in)
50 years	71.7 mm (2.8 in)
100 years	82.2 mm (3.2 in)	Longer than the 86 years of record

The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 86 years of values from 1916 to 2017.

A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.

The largest wettest-day totals in the fit: 85.9 mm (3.4 in) in 2014; 76.2 mm (3.0 in) in 1975; 65.5 mm (2.6 in) in 1968.

Station Changes

No change in the annual mean temperature of this station was found against its neighbours.

Climate Twins

2001 to 2017 against 1961 to 1990

Over 2001 to 2017, Roundup had a mean temperature of 9.3 C (48.7 F) and 365.8 mm (14.4 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Scipio (United States, 851 km away), Utah Lake Lehi (United States, 728 km away) and Whalen Dam (Usbr) (United States, 560 km away).

Climate twins of Roundup: stations whose 1961 to 1990 climate is closest to its 2001 to 2017 climate
Twin station	Country	Distance away	Mean temperature, 1961-1990	Rain a year, 1961-1990	Climate difference
Scipio	United States	851 km (529 mi)	8.9 C (48.0 F)	360.3 mm (14.2 in)	0.69
Utah Lake Lehi	United States	728 km (452 mi)	9.2 C (48.5 F)	287.9 mm (11.3 in)	0.71
Whalen Dam (Usbr)	United States	560 km (348 mi)	9.0 C (48.1 F)	330.0 mm (13.0 in)	0.72

Twins are stations, not cities. A twin is one of the three stations at least 100 km away whose earlier climate is closest to this station's recent one, so a close match does not mean the two places look alike in other ways. A station move or a gap in a record can change that station's averages. The list describes past climate; it is not a forecast and does not say what caused any change. How twins are found, and a search for any station.

Download the Data

Data for Roundup standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Roundup threshold days by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-12 (12 October 2026). Records are computed by this site and are not official.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).