Summit 1 W Weather Records (USC00398116)

Record envelope, standing records and threshold days for Summit 1 W (USC00398116), South Dakota, United States, with 71 years of record.

Key Facts for Summit 1 W

Summit 1 W (USC00398116) is a weather station in South Dakota, United States at 45.30 latitude and -97.06 longitude, 596 m (1,955 ft) above sea level.
The station reports from 1956 to 2026, 71 years of record.
1,464 records set at Summit 1 W still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Summit 1 W set a daily record high minimum temperature of 14.4 C (57.9 F) on 25 September 2026 (provisional).

Provisional Records

Records set in the last 60 days are provisional until they clear the revision window.

About the Station

Location: South Dakota, United States, 45.30 latitude, -97.06 longitude.
Elevation: 596 m (1,955 ft).
Period of record: 1956 to 2026, 71 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

12 days at or beyond a record

The band shows the record high and record low for each calendar day at Summit 1 W. The lines show the 2026 daily maximum and minimum. 12 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.

Daily record high and record low at Summit 1 W, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	17.8 C (64.0 F)	-38.9 C (-38.0 F)	7.2 C (45.0 F)	-30.6 C (-23.1 F)
Feb	16.7 C (62.1 F)	-40.0 C (-40.0 F)	13.3 C (55.9 F)	-21.1 C (-6.0 F)
Mar	27.2 C (81.0 F)	-32.2 C (-26.0 F)	22.2 C (72.0 F)	-21.7 C (-7.1 F)
Apr	34.4 C (93.9 F)	-21.7 C (-7.1 F)	30.6 C (87.1 F)	-11.1 C (12.0 F)
May	35.0 C (95.0 F)	-9.4 C (15.1 F)	32.8 C (91.0 F)	-5.0 C (23.0 F)
Jun	39.4 C (102.9 F)	-1.1 C (30.0 F)	32.2 C (90.0 F)	5.0 C (41.0 F)
Jul	39.4 C (102.9 F)	3.3 C (37.9 F)	35.6 C (96.1 F)	10.0 C (50.0 F)
Aug	38.9 C (102.0 F)	0.0 C (32.0 F)	30.0 C (86.0 F)	8.3 C (46.9 F)
Sep	36.1 C (97.0 F)	-9.4 C (15.1 F)	36.1 C (97.0 F)	5.0 C (41.0 F)
Oct	32.2 C (90.0 F)	-15.6 C (3.9 F)	27.8 C (82.0 F)	1.7 C (35.1 F)
Nov	24.4 C (75.9 F)	-31.7 C (-25.1 F)	n/a	n/a
Dec	17.8 C (64.0 F)	-36.7 C (-34.1 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Summit 1 W still stand. 1985 holds the most, with 41.

Standing records at Summit 1 W by the year they were set
Year set	Standing records
1956	8
1957	9
1958	21
1959	28
1960	9
1961	15
1962	32
1963	21
1964	31
1965	36
1966	27
1967	22
1968	20
1969	18
1970	19
1971	18
1972	23
1973	15
1974	24
1975	12
1976	35
1977	18
1978	12
1979	20
1980	16
1981	17
1982	7
1983	32
1984	19
1985	41
1986	20
1987	32
1988	40
1989	25
1990	27
1991	34
1992	38
1993	21
1994	20
1995	13
1996	25
1997	24
1998	20
1999	14
2000	31
2001	12
2002	15
2003	21
2004	27
2005	19
2006	18
2007	10
2008	11
2009	17
2010	13
2011	15
2012	36
2013	19
2014	16
2015	18
2016	9
2017	14
2018	21
2019	15
2020	28
2021	28
2022	8
2023	19
2024	20
2025	15
2026	11

All-Time Record Progression

6 new records

6 all-time records were set at Summit 1 W between 21 December 1989 and 16 July 2012. Each dot is a new record.

When Summit 1 W set new all-time records
Date	Kind	Detail
1989-12-21	Record low maximum temperature	Record low maximum temperature -28.9 C (-20.0 F)
1994-01-18	Record low maximum temperature	Record low maximum temperature -31.1 C (-24.0 F)
1994-02-09	Record low minimum temperature	Record low minimum temperature -40.0 C (-40.0 F)
1997-01-04	Record daily snowfall	Record daily snowfall 55.9 cm (22.0 in)
2011-07-19	Record high minimum temperature	Record high minimum temperature 25.0 C (77.0 F)
2012-07-16	Record high minimum temperature	Record high minimum temperature 25.6 C (78.1 F)

Wettest Day of Each Month

Jun: 142.5 mm (5.6 in)

The wettest day on record for each calendar month at Summit 1 W. The most was 142.5 mm (5.6 in) on 29 June 1971.

Record daily precipitation for each month at Summit 1 W
Month	Record daily precipitation (mm)	Date
Jan	18.3 mm (0.7 in)	30 January 2001
Feb	34.3 mm (1.4 in)	10 February 2013
Mar	69.9 mm (2.8 in)	12 March 1977
Apr	62.2 mm (2.4 in)	12 April 1991
May	82.6 mm (3.3 in)	24 May 1973
Jun	142.5 mm (5.6 in)	29 June 1971
Jul	92.7 mm (3.6 in)	13 July 1982
Aug	101.1 mm (4.0 in)	6 August 2022
Sep	102.1 mm (4.0 in)	20 September 2007
Oct	55.9 mm (2.2 in)	13 October 2023
Nov	47.5 mm (1.9 in)	1 November 2000
Dec	29.0 mm (1.1 in)	26 December 2023

Period of Record Coverage

1956 to 2026

71 years of record at Summit 1 W, 1956 to 2026. 4 years have data for under 90 percent of days and are left out of rankings: 1956, 1981, 1982, 2026.

Days with data per year at Summit 1 W
Year	Days with data	Share of year	Complete
1956	122	33%	No
1957	363	99%	Yes
1958	365	100%	Yes
1959	364	100%	Yes
1960	353	96%	Yes
1961	364	100%	Yes
1962	365	100%	Yes
1963	364	100%	Yes
1964	365	100%	Yes
1965	365	100%	Yes
1966	364	100%	Yes
1967	365	100%	Yes
1968	366	100%	Yes
1969	365	100%	Yes
1970	364	100%	Yes
1971	365	100%	Yes
1972	366	100%	Yes
1973	365	100%	Yes
1974	364	100%	Yes
1975	365	100%	Yes
1976	366	100%	Yes
1977	365	100%	Yes
1978	364	100%	Yes
1979	363	99%	Yes
1980	335	92%	Yes
1981	150	41%	No
1982	165	45%	No
1983	353	97%	Yes
1984	354	97%	Yes
1985	355	97%	Yes
1986	359	98%	Yes
1987	358	98%	Yes
1988	361	99%	Yes
1989	359	98%	Yes
1990	357	98%	Yes
1991	360	99%	Yes
1992	358	98%	Yes
1993	354	97%	Yes
1994	357	98%	Yes
1995	354	97%	Yes
1996	362	99%	Yes
1997	357	98%	Yes
1998	352	96%	Yes
1999	354	97%	Yes
2000	349	95%	Yes
2001	358	98%	Yes
2002	353	97%	Yes
2003	359	98%	Yes
2004	361	99%	Yes
2005	363	99%	Yes
2006	364	100%	Yes
2007	365	100%	Yes
2008	365	100%	Yes
2009	365	100%	Yes
2010	365	100%	Yes
2011	365	100%	Yes
2012	366	100%	Yes
2013	365	100%	Yes
2014	365	100%	Yes
2015	365	100%	Yes
2016	366	100%	Yes
2017	365	100%	Yes
2018	365	100%	Yes
2019	365	100%	Yes
2020	365	100%	Yes
2021	364	100%	Yes
2022	365	100%	Yes
2023	365	100%	Yes
2024	365	100%	Yes
2025	364	100%	Yes
2026	275	75%	No

Latest Records

Latest records at Summit 1 W
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
25 September 2026	Summit 1 W, US	daily high min (Provisional)	14.4 C (57.9 F)	1.6 C (2.9 F)	12 years	13 of 100 (Routine)
12 September 2026	Summit 1 W, US	daily high max (Provisional)	32.2 C (90.0 F)	0.5 C (0.9 F)	56 years	24 of 100 (Routine)
4 September 2026	Summit 1 W, US	monthly high max (Tie, Provisional)	36.1 C (97.0 F)	tie	3 years	4 of 100 (Routine)
5 August 2026	Summit 1 W, US	daily low max (Tie)	20.0 C (68.0 F)	tie	32 years	4 of 100 (Routine)
31 July 2026	Summit 1 W, US	daily rain	64.5 mm (2.5 in)	36.6 mm (1.4 in)	17 years	38 of 100 (Notable)
8 July 2026	Summit 1 W, US	daily rain	80.3 mm (3.2 in)	49.8 mm (2.0 in)	53 years	59 of 100 (Notable)
29 May 2026	Summit 1 W, US	daily high max (Tie)	31.1 C (88.0 F)	tie	20 years	3 of 100 (Routine)
26 May 2026	Summit 1 W, US	daily high max	32.8 C (91.0 F)	1.1 C (2.0 F)	8 years	10 of 100 (Routine)
23 May 2026	Summit 1 W, US	daily low max	10.6 C (51.1 F)	0.5 C (0.9 F)	33 years	17 of 100 (Routine)
23 April 2026	Summit 1 W, US	daily high max	30.6 C (87.1 F)	0.6 C (1.1 F)	16 years	12 of 100 (Routine)
4 April 2026	Summit 1 W, US	daily rain	16.3 mm (0.6 in)	2.3 mm (0.09 in)	68 years	20 of 100 (Routine)
26 March 2026	Summit 1 W, US	daily high max	22.2 C (72.0 F)	2.8 C (5.0 F)	57 years	27 of 100 (Routine)
22 March 2026	Summit 1 W, US	daily high max	21.7 C (71.1 F)	1.7 C (3.1 F)	13 years	13 of 100 (Routine)
20 March 2026	Summit 1 W, US	daily high max	19.4 C (66.9 F)	2.2 C (4.0 F)	11 years	12 of 100 (Routine)
16 March 2026	Summit 1 W, US	daily low max	-8.9 C (16.0 F)	2.2 C (4.0 F)	41 years	21 of 100 (Routine)
16 March 2026	Summit 1 W, US	daily low min	-21.7 C (-7.1 F)	1.7 C (3.1 F)	41 years	21 of 100 (Routine)
15 March 2026	Summit 1 W, US	daily snowfall	13.7 cm (5.4 in)	3.5 cm (1.4 in)	28 years	20 of 100 (Routine)
28 February 2026	Summit 1 W, US	daily snowfall	12.2 cm (4.8 in)	2.0 cm (0.8 in)	56 years	27 of 100 (Routine)
18 February 2026	Summit 1 W, US	daily rain	14.0 mm (0.6 in)	2.3 mm (0.09 in)	28 years	20 of 100 (Routine)
16 February 2026	Summit 1 W, US	daily high max	13.3 C (55.9 F)	0.5 C (0.9 F)	44 years	20 of 100 (Routine)

Climate Trend

65 complete years, 1957 to 2025

One stripe for each of 65 complete years at Summit 1 W, 1957 to 2025. Blue stripes are years cooler than the station's own mean of 5.6 C (42.0 F); red stripes are warmer. The coolest year was 1996, at 3.1 C (37.5 F), and the warmest was 2012, at 8.4 C (47.0 F). The strongest colour marks a difference of 2.9 C (5.2 F).

Annual mean temperature at Summit 1 W as warming stripes, 1957 to 2025
Year	Annual mean temperature	Difference from the station mean
1957	5.2 C	-0.40 C
1958	5.5 C	-0.07 C
1959	5.2 C	-0.40 C
1961	5.4 C	-0.14 C
1962	4.7 C	-0.81 C
1963	6.0 C	+0.43 C
1964	5.5 C	-0.10 C
1965	4.3 C	-1.26 C
1966	4.5 C	-1.04 C
1967	5.1 C	-0.49 C
1968	5.6 C	0.00 C
1969	4.6 C	-0.92 C
1970	4.8 C	-0.79 C
1971	5.0 C	-0.57 C
1972	4.0 C	-1.59 C
1973	6.3 C	+0.78 C
1974	5.4 C	-0.14 C
1975	4.8 C	-0.76 C
1976	5.8 C	+0.21 C
1977	5.4 C	-0.19 C
1978	4.0 C	-1.52 C
1979	3.7 C	-1.87 C
1983	5.0 C	-0.59 C
1984	5.3 C	-0.28 C
1985	4.0 C	-1.52 C
1986	5.5 C	-0.07 C
1987	7.9 C	+2.37 C
1988	6.2 C	+0.67 C
1989	4.4 C	-1.13 C
1990	6.5 C	+0.99 C
1991	6.3 C	+0.74 C
1992	5.3 C	-0.26 C
1993	3.7 C	-1.83 C
1994	4.9 C	-0.61 C
1995	4.8 C	-0.72 C
1996	3.1 C	-2.47 C
1997	4.6 C	-0.92 C
1998	7.0 C	+1.46 C
1999	7.0 C	+1.48 C
2000	5.9 C	+0.35 C
2001	6.1 C	+0.58 C
2002	6.1 C	+0.55 C
2003	5.6 C	+0.07 C
2004	6.0 C	+0.40 C
2005	6.6 C	+1.05 C
2006	6.8 C	+1.29 C
2007	6.0 C	+0.40 C
2008	4.8 C	-0.77 C
2009	5.0 C	-0.54 C
2010	6.3 C	+0.78 C
2011	5.8 C	+0.27 C
2012	8.4 C	+2.81 C
2013	4.6 C	-0.99 C
2014	4.9 C	-0.70 C
2015	7.1 C	+1.59 C
2016	7.3 C	+1.78 C
2017	6.3 C	+0.77 C
2018	5.1 C	-0.50 C
2019	4.2 C	-1.35 C
2020	6.6 C	+1.06 C
2021	7.6 C	+2.00 C
2022	5.4 C	-0.16 C
2023	6.8 C	+1.22 C
2024	7.5 C	+1.97 C
2025	6.0 C	+0.45 C

The annual mean temperature here has risen by 0.2 C (0.1 to 0.3) per decade over 1957 to 2025. In Fahrenheit: 0.4 F (0.2 to 0.6) per decade. The slope is a straight line fitted to 65 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Summit 1 W
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.2 C (0.1 to 0.3) per decade	0.4 F (0.2 to 0.6) per decade	1957 to 2025	65	Rise
Mean daily maximum	0.2 C (0.1 to 0.3) per decade	0.4 F (0.1 to 0.6) per decade	1957 to 2025	65	Rise
Mean daily minimum	0.2 C (0.1 to 0.4) per decade	0.4 F (0.2 to 0.6) per decade	1957 to 2025	65	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

1956 to 2026

Yearly extremes at Summit 1 W: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	39.4 C (102.9 F)	1966	34.4 C (93.9 F)	71
Coldest night (TNn)	-40.0 C (-40.0 F)	1994	-32.8 C (-27.0 F)	71
Wettest day (Rx1day)	142.5 mm (5.6 in)	1971	47.8 mm (1.9 in)	71
Wettest five days (Rx5day)	143.0 mm (5.6 in)	1971	80.2 mm (3.2 in)	71
Longest dry spell (CDD)	60 days	1959	31 days	71

Hottest day (TXx)

The hottest day of the year at Summit 1 W, 1956 to 2026. The record is 39.4 C (102.9 F) in 1966, marked on the chart; the median year is 34.4 C (93.9 F).

Hottest day (TXx) at Summit 1 W by year
Year	Hottest day (TXx)
1956	32.2 C (90.0 F)
1957	34.4 C (93.9 F)
1958	36.1 C (97.0 F)
1959	36.7 C (98.1 F)
1960	35.6 C (96.1 F)
1961	35.0 C (95.0 F)
1962	34.4 C (93.9 F)
1963	35.6 C (96.1 F)
1964	37.8 C (100.0 F)
1965	38.9 C (102.0 F)
1966	39.4 C (102.9 F)
1967	34.4 C (93.9 F)
1968	34.4 C (93.9 F)
1969	33.9 C (93.0 F)
1970	34.4 C (93.9 F)
1971	36.7 C (98.1 F)
1972	33.9 C (93.0 F)
1973	36.7 C (98.1 F)
1974	36.1 C (97.0 F)
1975	37.2 C (99.0 F)
1976	37.8 C (100.0 F)
1977	36.1 C (97.0 F)
1978	35.0 C (95.0 F)
1979	35.0 C (95.0 F)
1980	35.6 C (96.1 F)
1981	29.4 C (84.9 F)
1982	36.1 C (97.0 F)
1983	36.1 C (97.0 F)
1984	35.6 C (96.1 F)
1985	38.3 C (100.9 F)
1986	32.2 C (90.0 F)
1987	38.3 C (100.9 F)
1988	39.4 C (102.9 F)
1989	34.4 C (93.9 F)
1990	32.8 C (91.0 F)
1991	33.9 C (93.0 F)
1992	32.2 C (90.0 F)
1993	32.2 C (90.0 F)
1994	33.3 C (91.9 F)
1995	32.8 C (91.0 F)
1996	31.7 C (89.1 F)
1997	33.3 C (91.9 F)
1998	32.8 C (91.0 F)
1999	35.0 C (95.0 F)
2000	33.9 C (93.0 F)
2001	33.9 C (93.0 F)
2002	35.6 C (96.1 F)
2003	35.0 C (95.0 F)
2004	31.7 C (89.1 F)
2005	34.4 C (93.9 F)
2006	38.9 C (102.0 F)
2007	35.0 C (95.0 F)
2008	31.7 C (89.1 F)
2009	33.3 C (91.9 F)
2010	33.9 C (93.0 F)
2011	34.4 C (93.9 F)
2012	37.2 C (99.0 F)
2013	33.9 C (93.0 F)
2014	32.2 C (90.0 F)
2015	33.9 C (93.0 F)
2016	33.9 C (93.0 F)
2017	35.6 C (96.1 F)
2018	33.9 C (93.0 F)
2019	32.2 C (90.0 F)
2020	33.9 C (93.0 F)
2021	36.7 C (98.1 F)
2022	34.4 C (93.9 F)
2023	37.8 C (100.0 F)
2024	32.2 C (90.0 F)
2025	35.6 C (96.1 F)
2026	36.1 C (97.0 F)

Coldest night (TNn)

The coldest night of the year at Summit 1 W, 1956 to 2026. The record is -40.0 C (-40.0 F) in 1994, marked on the chart; the median year is -32.8 C (-27.0 F).

Coldest night (TNn) at Summit 1 W by year
Year	Coldest night (TNn)
1956	-24.4 C (-11.9 F)
1957	-33.3 C (-27.9 F)
1958	-31.7 C (-25.1 F)
1959	-32.8 C (-27.0 F)
1960	-32.8 C (-27.0 F)
1961	-35.0 C (-31.0 F)
1962	-33.9 C (-29.0 F)
1963	-34.4 C (-29.9 F)
1964	-29.4 C (-20.9 F)
1965	-33.3 C (-27.9 F)
1966	-34.4 C (-29.9 F)
1967	-36.7 C (-34.1 F)
1968	-35.0 C (-31.0 F)
1969	-30.0 C (-22.0 F)
1970	-35.0 C (-31.0 F)
1971	-33.3 C (-27.9 F)
1972	-37.2 C (-35.0 F)
1973	-31.7 C (-25.1 F)
1974	-34.4 C (-29.9 F)
1975	-31.1 C (-24.0 F)
1976	-33.9 C (-29.0 F)
1977	-37.2 C (-35.0 F)
1978	-33.3 C (-27.9 F)
1979	-32.8 C (-27.0 F)
1980	-30.6 C (-23.1 F)
1981	-32.8 C (-27.0 F)
1982	-22.2 C (-8.0 F)
1983	-36.7 C (-34.1 F)
1984	-36.7 C (-34.1 F)
1985	-36.1 C (-33.0 F)
1986	-33.9 C (-29.0 F)
1987	-32.8 C (-27.0 F)
1988	-35.6 C (-32.1 F)
1989	-35.6 C (-32.1 F)
1990	-36.1 C (-33.0 F)
1991	-28.9 C (-20.0 F)
1992	-29.4 C (-20.9 F)
1993	-33.9 C (-29.0 F)
1994	-40.0 C (-40.0 F)
1995	-31.7 C (-25.1 F)
1996	-37.8 C (-36.0 F)
1997	-32.8 C (-27.0 F)
1998	-31.7 C (-25.1 F)
1999	-32.8 C (-27.0 F)
2000	-31.1 C (-24.0 F)
2001	-31.7 C (-25.1 F)
2002	-27.2 C (-17.0 F)
2003	-32.8 C (-27.0 F)
2004	-32.2 C (-26.0 F)
2005	-35.0 C (-31.0 F)
2006	-30.0 C (-22.0 F)
2007	-31.1 C (-24.0 F)
2008	-34.4 C (-29.9 F)
2009	-37.2 C (-35.0 F)
2010	-35.0 C (-31.0 F)
2011	-33.9 C (-29.0 F)
2012	-28.3 C (-18.9 F)
2013	-30.6 C (-23.1 F)
2014	-31.7 C (-25.1 F)
2015	-28.3 C (-18.9 F)
2016	-33.3 C (-27.9 F)
2017	-33.9 C (-29.0 F)
2018	-31.1 C (-24.0 F)
2019	-38.9 C (-38.0 F)
2020	-31.1 C (-24.0 F)
2021	-35.0 C (-31.0 F)
2022	-30.6 C (-23.1 F)
2023	-30.6 C (-23.1 F)
2024	-29.4 C (-20.9 F)
2025	-31.7 C (-25.1 F)
2026	-30.6 C (-23.1 F)

Wettest day (Rx1day)

The wettest day of the year at Summit 1 W, 1956 to 2026. The record is 142.5 mm (5.6 in) in 1971, marked on the chart; the median year is 47.8 mm (1.9 in).

Wettest day (Rx1day) at Summit 1 W by year
Year	Wettest day (Rx1day)
1956	33.0 mm (1.3 in)
1957	74.9 mm (2.9 in)
1958	30.0 mm (1.2 in)
1959	42.4 mm (1.7 in)
1960	43.4 mm (1.7 in)
1961	64.0 mm (2.5 in)
1962	46.2 mm (1.8 in)
1963	54.6 mm (2.1 in)
1964	33.3 mm (1.3 in)
1965	46.0 mm (1.8 in)
1966	67.3 mm (2.6 in)
1967	38.1 mm (1.5 in)
1968	43.7 mm (1.7 in)
1969	34.3 mm (1.4 in)
1970	50.8 mm (2.0 in)
1971	142.5 mm (5.6 in)
1972	92.2 mm (3.6 in)
1973	82.6 mm (3.3 in)
1974	28.4 mm (1.1 in)
1975	24.9 mm (1.0 in)
1976	37.1 mm (1.5 in)
1977	69.9 mm (2.8 in)
1978	47.8 mm (1.9 in)
1979	48.8 mm (1.9 in)
1980	35.6 mm (1.4 in)
1981	31.2 mm (1.2 in)
1982	92.7 mm (3.6 in)
1983	47.0 mm (1.9 in)
1984	39.4 mm (1.6 in)
1985	44.5 mm (1.8 in)
1986	70.4 mm (2.8 in)
1987	32.5 mm (1.3 in)
1988	63.2 mm (2.5 in)
1989	74.9 mm (2.9 in)
1990	33.0 mm (1.3 in)
1991	62.2 mm (2.4 in)
1992	43.2 mm (1.7 in)
1993	54.6 mm (2.1 in)
1994	69.3 mm (2.7 in)
1995	71.4 mm (2.8 in)
1996	45.2 mm (1.8 in)
1997	47.0 mm (1.9 in)
1998	45.7 mm (1.8 in)
1999	37.8 mm (1.5 in)
2000	47.5 mm (1.9 in)
2001	47.8 mm (1.9 in)
2002	56.4 mm (2.2 in)
2003	33.3 mm (1.3 in)
2004	60.2 mm (2.4 in)
2005	35.8 mm (1.4 in)
2006	49.0 mm (1.9 in)
2007	102.1 mm (4.0 in)
2008	75.2 mm (3.0 in)
2009	65.5 mm (2.6 in)
2010	41.9 mm (1.6 in)
2011	39.1 mm (1.5 in)
2012	38.4 mm (1.5 in)
2013	48.5 mm (1.9 in)
2014	48.5 mm (1.9 in)
2015	44.5 mm (1.8 in)
2016	60.5 mm (2.4 in)
2017	73.9 mm (2.9 in)
2018	49.5 mm (1.9 in)
2019	64.8 mm (2.6 in)
2020	41.4 mm (1.6 in)
2021	76.7 mm (3.0 in)
2022	101.1 mm (4.0 in)
2023	55.9 mm (2.2 in)
2024	32.0 mm (1.3 in)
2025	65.0 mm (2.6 in)
2026	80.3 mm (3.2 in)

Wettest five days (Rx5day)

The wettest five days of the year at Summit 1 W, 1956 to 2026. The record is 143.0 mm (5.6 in) in 1971, marked on the chart; the median year is 80.2 mm (3.2 in).

Wettest five days (Rx5day) at Summit 1 W by year
Year	Wettest five days (Rx5day)
1956	35.3 mm (1.4 in)
1957	98.5 mm (3.9 in)
1958	50.6 mm (2.0 in)
1959	60.7 mm (2.4 in)
1960	48.4 mm (1.9 in)
1961	96.3 mm (3.8 in)
1962	138.0 mm (5.4 in)
1963	119.1 mm (4.7 in)
1964	44.9 mm (1.8 in)
1965	76.7 mm (3.0 in)
1966	77.3 mm (3.0 in)
1967	57.9 mm (2.3 in)
1968	66.6 mm (2.6 in)
1969	48.9 mm (1.9 in)
1970	71.9 mm (2.8 in)
1971	143.0 mm (5.6 in)
1972	96.0 mm (3.8 in)
1973	93.6 mm (3.7 in)
1974	52.0 mm (2.0 in)
1975	44.7 mm (1.8 in)
1976	37.9 mm (1.5 in)
1977	80.6 mm (3.2 in)
1978	77.6 mm (3.1 in)
1979	109.5 mm (4.3 in)
1980	83.1 mm (3.3 in)
1981	38.9 mm (1.5 in)
1982	97.5 mm (3.8 in)
1983	86.4 mm (3.4 in)
1984	79.0 mm (3.1 in)
1985	88.9 mm (3.5 in)
1986	99.1 mm (3.9 in)
1987	47.0 mm (1.9 in)
1988	81.9 mm (3.2 in)
1989	76.2 mm (3.0 in)
1990	78.1 mm (3.1 in)
1991	81.5 mm (3.2 in)
1992	102.8 mm (4.0 in)
1993	98.1 mm (3.9 in)
1994	95.8 mm (3.8 in)
1995	110.8 mm (4.4 in)
1996	47.2 mm (1.9 in)
1997	76.7 mm (3.0 in)
1998	85.8 mm (3.4 in)
1999	66.0 mm (2.6 in)
2000	57.1 mm (2.2 in)
2001	83.3 mm (3.3 in)
2002	76.0 mm (3.0 in)
2003	66.5 mm (2.6 in)
2004	82.4 mm (3.2 in)
2005	70.4 mm (2.8 in)
2006	85.3 mm (3.4 in)
2007	139.2 mm (5.5 in)
2008	89.9 mm (3.5 in)
2009	80.2 mm (3.2 in)
2010	56.2 mm (2.2 in)
2011	56.4 mm (2.2 in)
2012	73.2 mm (2.9 in)
2013	106.9 mm (4.2 in)
2014	75.4 mm (3.0 in)
2015	53.1 mm (2.1 in)
2016	109.8 mm (4.3 in)
2017	95.8 mm (3.8 in)
2018	69.3 mm (2.7 in)
2019	99.4 mm (3.9 in)
2020	52.3 mm (2.1 in)
2021	91.7 mm (3.6 in)
2022	107.2 mm (4.2 in)
2023	111.3 mm (4.4 in)
2024	66.7 mm (2.6 in)
2025	86.4 mm (3.4 in)
2026	94.5 mm (3.7 in)

Longest dry spell (CDD)

The longest dry spell of the year at Summit 1 W, 1956 to 2026. The record is 60 days in 1959, marked on the chart; the median year is 31 days.

Longest dry spell (CDD) at Summit 1 W by year
Year	Longest dry spell (CDD)
1956	33 days
1957	28 days
1958	31 days
1959	60 days
1960	31 days
1961	35 days
1962	38 days
1963	31 days
1964	49 days
1965	23 days
1966	35 days
1967	32 days
1968	40 days
1969	49 days
1970	36 days
1971	53 days
1972	29 days
1973	23 days
1974	43 days
1975	35 days
1976	47 days
1977	25 days
1978	35 days
1979	36 days
1980	34 days
1981	30 days
1982	51 days
1983	25 days
1984	31 days
1985	23 days
1986	42 days
1987	23 days
1988	29 days
1989	23 days
1990	42 days
1991	30 days
1992	25 days
1993	20 days
1994	24 days
1995	15 days
1996	31 days
1997	20 days
1998	32 days
1999	31 days
2000	23 days
2001	30 days
2002	22 days
2003	34 days
2004	23 days
2005	28 days
2006	31 days
2007	21 days
2008	41 days
2009	21 days
2010	22 days
2011	40 days
2012	49 days
2013	34 days
2014	18 days
2015	29 days
2016	23 days
2017	50 days
2018	29 days
2019	26 days
2020	38 days
2021	35 days
2022	36 days
2023	25 days
2024	36 days
2025	21 days
2026	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

65 years with a frost

Across 65 years with a frost, the median last spring frost at Summit 1 W falls on 17 May and the median first autumn frost on 23 September, which leaves a median of 132 days between them.

In 1996 to 2025 the median growing season was 141 days. That is 16 days more than in 1957 to 1990.

Fitted over all years, the growing season changes by +2.6 days per decade at this station.

Frost dates and growing season at Summit 1 W
Measure	Median, all years	Earliest period (1957 to 1990)	Recent period (1996 to 2025)	Recent against earliest	Fitted trend
Last spring frost	17 May	19 May	15 May	4 days earlier	-0.8 days per decade
First autumn frost	23 September	21 September	29 September	8 days later	+1.8 days per decade
Growing days	132 days	125 days	141 days	16 days more	+2.6 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

67 years, 1957 to 2025

A day with at least 49.5 mm (1.9 in) of rain is expected about once in 2 years. A day with at least 126.8 mm (5.0 in) of rain is expected about once in 100 years.

Rainfall return levels at Summit 1 W: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	49.5 mm (1.9 in)
5 years	66.6 mm (2.6 in)
10 years	79.3 mm (3.1 in)
25 years	96.9 mm (3.8 in)
50 years	111.3 mm (4.4 in)
100 years	126.8 mm (5.0 in)	Longer than the 67 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, 67 years of values from 1957 to 2025.

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: 142.5 mm (5.6 in) in 1971; 102.1 mm (4.0 in) in 2007; 101.1 mm (4.0 in) in 2022.

Station Changes

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

Climate Twins

2011 to 2025 against 1961 to 1990

Over 2011 to 2025, Summit 1 W had a mean temperature of 6.2 C (43.2 F) and 630.0 mm (24.8 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are Tyler (United States, 136 km away), Flandreau (United States, 144 km away) and Worthington 2 NNE (United States, 219 km away).

Climate twins of Summit 1 W: stations whose 1961 to 1990 climate is closest to its 2011 to 2025 climate
Twin station	Country	Distance away	Mean temperature, 1961-1990	Rain a year, 1961-1990	Climate difference
Tyler	United States	136 km (85 mi)	6.5 C (43.8 F)	614.0 mm (24.2 in)	0.96
Flandreau	United States	144 km (89 mi)	6.5 C (43.6 F)	547.9 mm (21.6 in)	0.98
Worthington 2 NNE	United States	219 km (136 mi)	6.4 C (43.5 F)	677.1 mm (26.7 in)	1.04

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 Summit 1 W standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Summit 1 W 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.

Data as of 2026-10-14. Last revised 14 October 2026 (2026-10-14).