Record envelope, standing records and threshold days for Harlowton (USC00243939), Montana, United States, with 79 years of record.
Key Facts for Harlowton
Harlowton (USC00243939) is a weather station in Montana, United States at 46.44 latitude and -109.84 longitude, 1,287 m (4,222 ft) above sea level.
The station reports from 1948 to 2026, 79 years of record.
1,464 records set at Harlowton still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Harlowton tied a daily record low maximum temperature of 15.6 C (60.1 F) on 13 August 2026.
About the Station
Location: Montana, United States, 46.44 latitude, -109.84 longitude.
Elevation: 1,287 m (4,222 ft).
Period of record: 1948 to 2026, 79 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
16 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Harlowton. The lines show the 2026 daily maximum and minimum. 16 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Harlowton, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
20.6 C (69.1 F)
-40.6 C (-41.1 F)
16.1 C (61.0 F)
-26.7 C (-16.1 F)
Feb
23.3 C (73.9 F)
-39.4 C (-38.9 F)
20.6 C (69.1 F)
-22.2 C (-8.0 F)
Mar
25.6 C (78.1 F)
-33.9 C (-29.0 F)
25.6 C (78.1 F)
-22.2 C (-8.0 F)
Apr
30.6 C (87.1 F)
-21.1 C (-6.0 F)
27.8 C (82.0 F)
-7.8 C (18.0 F)
May
32.8 C (91.0 F)
-15.6 C (3.9 F)
32.2 C (90.0 F)
-6.7 C (19.9 F)
Jun
37.2 C (99.0 F)
-4.4 C (24.1 F)
31.1 C (88.0 F)
0.0 C (32.0 F)
Jul
41.1 C (106.0 F)
0.6 C (33.1 F)
41.1 C (106.0 F)
7.8 C (46.0 F)
Aug
38.9 C (102.0 F)
-4.4 C (24.1 F)
38.9 C (102.0 F)
4.4 C (39.9 F)
Sep
37.8 C (100.0 F)
-12.2 C (10.0 F)
n/a
n/a
Oct
32.2 C (90.0 F)
-22.2 C (-8.0 F)
n/a
n/a
Nov
25.6 C (78.1 F)
-33.9 C (-29.0 F)
n/a
n/a
Dec
18.9 C (66.0 F)
-39.4 C (-38.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Harlowton still stand. 1951 holds the most, with 44.
Standing records at Harlowton by the year they were set
Year set
Standing records
1948
16
1949
29
1950
33
1951
44
1952
19
1953
21
1954
24
1955
18
1956
25
1957
12
1958
11
1959
17
1960
27
1961
19
1962
29
1963
16
1964
12
1965
31
1966
16
1967
18
1968
21
1969
24
1970
8
1971
19
1972
29
1973
20
1974
14
1975
16
1976
14
1977
17
1978
17
1979
8
1980
25
1981
17
1982
14
1983
22
1984
20
1985
33
1986
18
1987
28
1988
22
1989
21
1990
19
1991
12
1992
29
1993
14
1994
12
1995
11
1996
29
1997
14
1998
12
1999
16
2000
24
2001
11
2002
20
2003
16
2004
15
2005
11
2006
1
2007
12
2008
11
2009
10
2010
10
2011
12
2012
29
2013
21
2014
16
2015
21
2016
15
2017
21
2018
17
2019
21
2020
3
2021
16
2022
18
2023
15
2024
24
2025
20
2026
22
All-Time Record Progression
5 new records
5 all-time records were set at Harlowton between 2 February 1989 and 12 July 2026. Each dot is a new record.
When Harlowton set new all-time records
Date
Kind
Detail
1989-02-02
Record low maximum temperature
Record low maximum temperature -28.9 C (-20.0 F)
1997-06-06
Record daily precipitation
Record daily precipitation 62.0 mm (2.4 in)
2002-07-12
Record high maximum temperature
Record high maximum temperature 39.4 C (102.9 F)
2024-01-12
Record low minimum temperature
Record low minimum temperature -40.6 C (-41.1 F)
2026-07-12
Record high maximum temperature
Record high maximum temperature 41.1 C (106.0 F)
Wettest Day of Each Month
Jun: 62.0 mm (2.4 in)
The wettest day on record for each calendar month at Harlowton. The most was 62.0 mm (2.4 in) on 6 June 1997.
Record daily precipitation for each month at Harlowton
Month
Record daily precipitation (mm)
Date
Jan
20.1 mm (0.8 in)
26 January 1975
Feb
24.6 mm (1.0 in)
28 February 1953
Mar
17.8 mm (0.7 in)
28 March 2007
Apr
43.2 mm (1.7 in)
28 April 1950
May
50.0 mm (2.0 in)
30 May 1967
Jun
62.0 mm (2.4 in)
6 June 1997
Jul
33.3 mm (1.3 in)
3 July 1993
Aug
37.6 mm (1.5 in)
30 August 2010
Sep
50.8 mm (2.0 in)
18 September 2024
Oct
31.5 mm (1.2 in)
23 October 2022
Nov
25.4 mm (1.0 in)
3 November 2017
Dec
22.9 mm (0.9 in)
23 December 1955
Period of Record Coverage
1948 to 2026
Complete yearUnder 90 percent of days
79 years of record at Harlowton, 1948 to 2026. 12 years have data for under 90 percent of days and are left out of rankings: 1948, 2003, 2005, 2006, 2007, 2008, 2009, 2010 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 62 complete years at Harlowton, 1950 to 2025. Blue stripes are years cooler than the station's own mean of 6.8 C (44.2 F); red stripes are warmer. The coolest year was 1951, at 3.5 C (38.4 F), and the warmest was 1987, at 8.5 C (47.3 F). The strongest colour marks a difference of 3.3 C (5.9 F).
Annual mean temperature at Harlowton as warming stripes, 1950 to 2025
Year
Annual mean temperature
Difference from the station mean
1950
5.2 C
-1.61 C
1951
3.5 C
-3.25 C
1952
6.3 C
-0.49 C
1953
7.0 C
+0.21 C
1954
6.0 C
-0.77 C
1955
5.2 C
-1.63 C
1956
6.8 C
+0.00 C
1957
6.4 C
-0.42 C
1958
7.5 C
+0.67 C
1959
6.1 C
-0.67 C
1960
6.6 C
-0.20 C
1961
7.5 C
+0.67 C
1962
6.9 C
+0.11 C
1963
7.3 C
+0.49 C
1964
5.8 C
-0.97 C
1965
5.4 C
-1.35 C
1966
6.3 C
-0.53 C
1967
6.1 C
-0.69 C
1968
6.0 C
-0.74 C
1969
6.2 C
-0.56 C
1970
6.5 C
-0.26 C
1971
6.4 C
-0.38 C
1972
6.2 C
-0.57 C
1973
6.8 C
+0.06 C
1974
7.5 C
+0.68 C
1975
5.6 C
-1.18 C
1976
7.7 C
+0.91 C
1977
7.0 C
+0.23 C
1978
5.4 C
-1.40 C
1979
6.5 C
-0.28 C
1980
7.1 C
+0.34 C
1981
8.1 C
+1.33 C
1982
5.8 C
-0.97 C
1983
7.0 C
+0.25 C
1984
7.1 C
+0.27 C
1985
6.0 C
-0.83 C
1986
7.9 C
+1.12 C
1987
8.5 C
+1.73 C
1988
8.4 C
+1.64 C
1989
6.5 C
-0.27 C
1991
7.6 C
+0.86 C
1992
7.8 C
+1.00 C
1993
6.2 C
-0.57 C
1994
7.6 C
+0.83 C
1995
7.1 C
+0.30 C
1996
5.6 C
-1.14 C
1997
7.2 C
+0.42 C
1998
7.6 C
+0.78 C
1999
8.2 C
+1.40 C
2000
7.3 C
+0.50 C
2001
7.9 C
+1.13 C
2002
6.8 C
-0.01 C
2004
7.7 C
+0.95 C
2013
7.4 C
+0.59 C
2014
6.5 C
-0.24 C
2015
7.9 C
+1.07 C
2016
7.7 C
+0.88 C
2018
5.7 C
-1.07 C
2022
6.5 C
-0.26 C
2023
7.2 C
+0.39 C
2024
7.4 C
+0.62 C
2025
7.4 C
+0.60 C
The annual mean temperature here has risen by 0.2 C (0.1 to 0.3) per decade over 1950 to 2025. In Fahrenheit: 0.3 F (0.2 to 0.5) per decade. The slope is a straight line fitted to 62 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Harlowton
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (0.1 to 0.3) per decade
0.3 F (0.2 to 0.5) per decade
1950 to 2025
62
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.4 F (0.1 to 0.6) per decade
1950 to 2025
62
Rise
Mean daily minimum
0.2 C (0.1 to 0.3) per decade
0.3 F (0.2 to 0.5) per decade
1950 to 2025
62
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
1948 to 2026
Yearly extremes at Harlowton: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
41.1 C (106.0 F)
2026
36.1 C (97.0 F)
79
Coldest night (TNn)
-40.6 C (-41.1 F)
2024
-31.1 C (-24.0 F)
79
Wettest day (Rx1day)
62.0 mm (2.4 in)
1997
28.7 mm (1.1 in)
79
Wettest five days (Rx5day)
92.7 mm (3.6 in)
1962
43.4 mm (1.7 in)
79
Longest dry spell (CDD)
73 days
2004
39 days
79
Hottest day (TXx)
The hottest day of the year at Harlowton, 1948 to 2026. The record is 41.1 C (106.0 F) in 2026, marked on the chart; the median year is 36.1 C (97.0 F).
Hottest day (TXx) at Harlowton by year
Year
Hottest day (TXx)
1948
36.1 C (97.0 F)
1949
36.7 C (98.1 F)
1950
35.6 C (96.1 F)
1951
37.8 C (100.0 F)
1952
36.1 C (97.0 F)
1953
38.3 C (100.9 F)
1954
37.8 C (100.0 F)
1955
37.2 C (99.0 F)
1956
35.0 C (95.0 F)
1957
36.7 C (98.1 F)
1958
33.9 C (93.0 F)
1959
34.4 C (93.9 F)
1960
37.2 C (99.0 F)
1961
38.3 C (100.9 F)
1962
33.3 C (91.9 F)
1963
36.1 C (97.0 F)
1964
36.1 C (97.0 F)
1965
34.4 C (93.9 F)
1966
36.7 C (98.1 F)
1967
34.4 C (93.9 F)
1968
33.3 C (91.9 F)
1969
37.2 C (99.0 F)
1970
36.1 C (97.0 F)
1971
36.1 C (97.0 F)
1972
33.9 C (93.0 F)
1973
36.7 C (98.1 F)
1974
35.0 C (95.0 F)
1975
34.4 C (93.9 F)
1976
35.0 C (95.0 F)
1977
33.3 C (91.9 F)
1978
34.4 C (93.9 F)
1979
35.6 C (96.1 F)
1980
36.1 C (97.0 F)
1981
35.6 C (96.1 F)
1982
34.4 C (93.9 F)
1983
37.8 C (100.0 F)
1984
36.7 C (98.1 F)
1985
36.1 C (97.0 F)
1986
35.0 C (95.0 F)
1987
34.4 C (93.9 F)
1988
36.7 C (98.1 F)
1989
36.7 C (98.1 F)
1990
36.7 C (98.1 F)
1991
35.0 C (95.0 F)
1992
35.6 C (96.1 F)
1993
33.3 C (91.9 F)
1994
35.6 C (96.1 F)
1995
36.1 C (97.0 F)
1996
36.1 C (97.0 F)
1997
33.3 C (91.9 F)
1998
36.7 C (98.1 F)
1999
36.7 C (98.1 F)
2000
37.8 C (100.0 F)
2001
37.8 C (100.0 F)
2002
39.4 C (102.9 F)
2003
36.1 C (97.0 F)
2004
36.1 C (97.0 F)
2005
35.6 C (96.1 F)
2006
37.8 C (100.0 F)
2007
38.9 C (102.0 F)
2008
37.2 C (99.0 F)
2009
36.7 C (98.1 F)
2010
35.0 C (95.0 F)
2011
37.2 C (99.0 F)
2012
37.2 C (99.0 F)
2013
35.0 C (95.0 F)
2014
34.4 C (93.9 F)
2015
35.0 C (95.0 F)
2016
35.6 C (96.1 F)
2017
36.7 C (98.1 F)
2018
36.7 C (98.1 F)
2019
33.9 C (93.0 F)
2020
35.0 C (95.0 F)
2021
37.8 C (100.0 F)
2022
37.8 C (100.0 F)
2023
36.7 C (98.1 F)
2024
38.3 C (100.9 F)
2025
35.6 C (96.1 F)
2026
41.1 C (106.0 F)
Coldest night (TNn)
The coldest night of the year at Harlowton, 1948 to 2026. The record is -40.6 C (-41.1 F) in 2024, marked on the chart; the median year is -31.1 C (-24.0 F).
Coldest night (TNn) at Harlowton by year
Year
Coldest night (TNn)
1948
-29.4 C (-20.9 F)
1949
-39.4 C (-38.9 F)
1950
-33.9 C (-29.0 F)
1951
-33.9 C (-29.0 F)
1952
-30.6 C (-23.1 F)
1953
-23.9 C (-11.0 F)
1954
-37.2 C (-35.0 F)
1955
-31.1 C (-24.0 F)
1956
-34.4 C (-29.9 F)
1957
-38.9 C (-38.0 F)
1958
-23.3 C (-9.9 F)
1959
-33.9 C (-29.0 F)
1960
-29.4 C (-20.9 F)
1961
-27.2 C (-17.0 F)
1962
-33.9 C (-29.0 F)
1963
-33.9 C (-29.0 F)
1964
-39.4 C (-38.9 F)
1965
-32.2 C (-26.0 F)
1966
-32.2 C (-26.0 F)
1967
-27.8 C (-18.0 F)
1968
-38.9 C (-38.0 F)
1969
-38.3 C (-36.9 F)
1970
-25.6 C (-14.1 F)
1971
-30.0 C (-22.0 F)
1972
-37.8 C (-36.0 F)
1973
-31.1 C (-24.0 F)
1974
-31.7 C (-25.1 F)
1975
-30.0 C (-22.0 F)
1976
-30.6 C (-23.1 F)
1977
-29.4 C (-20.9 F)
1978
-31.1 C (-24.0 F)
1979
-30.6 C (-23.1 F)
1980
-30.6 C (-23.1 F)
1981
-31.7 C (-25.1 F)
1982
-32.8 C (-27.0 F)
1983
-38.9 C (-38.0 F)
1984
-30.6 C (-23.1 F)
1985
-32.8 C (-27.0 F)
1986
-28.3 C (-18.9 F)
1987
-26.1 C (-15.0 F)
1988
-28.9 C (-20.0 F)
1989
-37.2 C (-35.0 F)
1990
-36.7 C (-34.1 F)
1991
-26.1 C (-15.0 F)
1992
-31.1 C (-24.0 F)
1993
-28.9 C (-20.0 F)
1994
-35.6 C (-32.1 F)
1995
-27.8 C (-18.0 F)
1996
-36.7 C (-34.1 F)
1997
-34.4 C (-29.9 F)
1998
-36.7 C (-34.1 F)
1999
-22.8 C (-9.0 F)
2000
-31.1 C (-24.0 F)
2001
-27.8 C (-18.0 F)
2002
-27.2 C (-17.0 F)
2003
-22.2 C (-8.0 F)
2004
-32.2 C (-26.0 F)
2005
-34.4 C (-29.9 F)
2006
-31.1 C (-24.0 F)
2007
-26.7 C (-16.1 F)
2008
-31.1 C (-24.0 F)
2009
-29.4 C (-20.9 F)
2010
-31.1 C (-24.0 F)
2011
-33.3 C (-27.9 F)
2012
-25.0 C (-13.0 F)
2013
-32.2 C (-26.0 F)
2014
-34.4 C (-29.9 F)
2015
-26.7 C (-16.1 F)
2016
-36.1 C (-33.0 F)
2017
-27.8 C (-18.0 F)
2018
-32.8 C (-27.0 F)
2019
-33.9 C (-29.0 F)
2020
-26.1 C (-15.0 F)
2021
-31.1 C (-24.0 F)
2022
-33.3 C (-27.9 F)
2023
-30.6 C (-23.1 F)
2024
-40.6 C (-41.1 F)
2025
-36.7 C (-34.1 F)
2026
-26.7 C (-16.1 F)
Wettest day (Rx1day)
The wettest day of the year at Harlowton, 1948 to 2026. The record is 62.0 mm (2.4 in) in 1997, marked on the chart; the median year is 28.7 mm (1.1 in).
Wettest day (Rx1day) at Harlowton by year
Year
Wettest day (Rx1day)
1948
20.3 mm (0.8 in)
1949
28.2 mm (1.1 in)
1950
43.2 mm (1.7 in)
1951
14.2 mm (0.6 in)
1952
17.0 mm (0.7 in)
1953
24.6 mm (1.0 in)
1954
53.3 mm (2.1 in)
1955
41.9 mm (1.6 in)
1956
22.6 mm (0.9 in)
1957
45.2 mm (1.8 in)
1958
22.6 mm (0.9 in)
1959
36.3 mm (1.4 in)
1960
22.6 mm (0.9 in)
1961
16.0 mm (0.6 in)
1962
33.0 mm (1.3 in)
1963
28.2 mm (1.1 in)
1964
36.8 mm (1.4 in)
1965
26.9 mm (1.1 in)
1966
22.1 mm (0.9 in)
1967
50.0 mm (2.0 in)
1968
24.4 mm (1.0 in)
1969
53.3 mm (2.1 in)
1970
30.0 mm (1.2 in)
1971
28.4 mm (1.1 in)
1972
21.6 mm (0.9 in)
1973
23.1 mm (0.9 in)
1974
35.6 mm (1.4 in)
1975
60.5 mm (2.4 in)
1976
40.4 mm (1.6 in)
1977
22.4 mm (0.9 in)
1978
30.7 mm (1.2 in)
1979
41.4 mm (1.6 in)
1980
35.3 mm (1.4 in)
1981
34.0 mm (1.3 in)
1982
33.8 mm (1.3 in)
1983
27.7 mm (1.1 in)
1984
29.0 mm (1.1 in)
1985
36.1 mm (1.4 in)
1986
19.6 mm (0.8 in)
1987
28.7 mm (1.1 in)
1988
26.7 mm (1.1 in)
1989
25.9 mm (1.0 in)
1990
26.7 mm (1.1 in)
1991
28.4 mm (1.1 in)
1992
57.9 mm (2.3 in)
1993
33.3 mm (1.3 in)
1994
34.0 mm (1.3 in)
1995
48.5 mm (1.9 in)
1996
30.2 mm (1.2 in)
1997
62.0 mm (2.4 in)
1998
37.8 mm (1.5 in)
1999
20.8 mm (0.8 in)
2000
17.8 mm (0.7 in)
2001
33.0 mm (1.3 in)
2002
26.7 mm (1.1 in)
2003
23.6 mm (0.9 in)
2004
31.5 mm (1.2 in)
2005
34.8 mm (1.4 in)
2006
26.7 mm (1.1 in)
2007
19.1 mm (0.8 in)
2008
41.9 mm (1.6 in)
2009
20.3 mm (0.8 in)
2010
37.6 mm (1.5 in)
2011
43.9 mm (1.7 in)
2012
17.8 mm (0.7 in)
2013
50.8 mm (2.0 in)
2014
20.3 mm (0.8 in)
2015
15.5 mm (0.6 in)
2016
24.4 mm (1.0 in)
2017
41.9 mm (1.6 in)
2018
40.6 mm (1.6 in)
2019
16.0 mm (0.6 in)
2020
22.9 mm (0.9 in)
2021
20.8 mm (0.8 in)
2022
31.5 mm (1.2 in)
2023
20.8 mm (0.8 in)
2024
50.8 mm (2.0 in)
2025
20.6 mm (0.8 in)
2026
30.2 mm (1.2 in)
Wettest five days (Rx5day)
The wettest five days of the year at Harlowton, 1948 to 2026. The record is 92.7 mm (3.6 in) in 1962, marked on the chart; the median year is 43.4 mm (1.7 in).
Wettest five days (Rx5day) at Harlowton by year
Year
Wettest five days (Rx5day)
1948
24.2 mm (1.0 in)
1949
48.5 mm (1.9 in)
1950
43.7 mm (1.7 in)
1951
19.1 mm (0.8 in)
1952
21.4 mm (0.8 in)
1953
31.0 mm (1.2 in)
1954
56.8 mm (2.2 in)
1955
45.0 mm (1.8 in)
1956
30.5 mm (1.2 in)
1957
53.1 mm (2.1 in)
1958
37.4 mm (1.5 in)
1959
40.7 mm (1.6 in)
1960
30.1 mm (1.2 in)
1961
28.7 mm (1.1 in)
1962
92.7 mm (3.6 in)
1963
52.4 mm (2.1 in)
1964
85.5 mm (3.4 in)
1965
44.3 mm (1.7 in)
1966
31.5 mm (1.2 in)
1967
61.7 mm (2.4 in)
1968
55.1 mm (2.2 in)
1969
82.5 mm (3.2 in)
1970
55.1 mm (2.2 in)
1971
45.4 mm (1.8 in)
1972
43.3 mm (1.7 in)
1973
33.3 mm (1.3 in)
1974
47.1 mm (1.9 in)
1975
62.6 mm (2.5 in)
1976
58.7 mm (2.3 in)
1977
35.8 mm (1.4 in)
1978
39.3 mm (1.5 in)
1979
85.7 mm (3.4 in)
1980
53.6 mm (2.1 in)
1981
44.9 mm (1.8 in)
1982
71.4 mm (2.8 in)
1983
35.8 mm (1.4 in)
1984
36.8 mm (1.4 in)
1985
54.1 mm (2.1 in)
1986
39.4 mm (1.6 in)
1987
46.5 mm (1.8 in)
1988
28.0 mm (1.1 in)
1989
32.0 mm (1.3 in)
1990
29.8 mm (1.2 in)
1991
49.7 mm (2.0 in)
1992
75.9 mm (3.0 in)
1993
46.3 mm (1.8 in)
1994
53.3 mm (2.1 in)
1995
67.9 mm (2.7 in)
1996
43.4 mm (1.7 in)
1997
92.7 mm (3.6 in)
1998
51.3 mm (2.0 in)
1999
34.5 mm (1.4 in)
2000
25.9 mm (1.0 in)
2001
50.3 mm (2.0 in)
2002
43.8 mm (1.7 in)
2003
39.2 mm (1.5 in)
2004
53.6 mm (2.1 in)
2005
63.9 mm (2.5 in)
2006
32.1 mm (1.3 in)
2007
19.3 mm (0.8 in)
2008
75.4 mm (3.0 in)
2009
22.9 mm (0.9 in)
2010
55.4 mm (2.2 in)
2011
24.1 mm (0.9 in)
2012
32.3 mm (1.3 in)
2013
51.3 mm (2.0 in)
2014
20.6 mm (0.8 in)
2015
17.5 mm (0.7 in)
2016
24.4 mm (1.0 in)
2017
44.2 mm (1.7 in)
2018
40.6 mm (1.6 in)
2019
17.8 mm (0.7 in)
2020
40.7 mm (1.6 in)
2021
33.8 mm (1.3 in)
2022
37.6 mm (1.5 in)
2023
34.1 mm (1.3 in)
2024
53.3 mm (2.1 in)
2025
25.4 mm (1.0 in)
2026
41.6 mm (1.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Harlowton, 1948 to 2026. The record is 73 days in 2004, marked on the chart; the median year is 39 days.
Longest dry spell (CDD) at Harlowton by year
Year
Longest dry spell (CDD)
1948
35 days
1949
49 days
1950
44 days
1951
44 days
1952
33 days
1953
45 days
1954
67 days
1955
55 days
1956
34 days
1957
68 days
1958
29 days
1959
31 days
1960
49 days
1961
40 days
1962
41 days
1963
59 days
1964
55 days
1965
47 days
1966
24 days
1967
60 days
1968
25 days
1969
38 days
1970
39 days
1971
38 days
1972
27 days
1973
29 days
1974
45 days
1975
25 days
1976
33 days
1977
37 days
1978
29 days
1979
39 days
1980
27 days
1981
39 days
1982
21 days
1983
43 days
1984
24 days
1985
38 days
1986
32 days
1987
48 days
1988
33 days
1989
17 days
1990
61 days
1991
32 days
1992
60 days
1993
24 days
1994
25 days
1995
29 days
1996
32 days
1997
49 days
1998
42 days
1999
29 days
2000
36 days
2001
40 days
2002
27 days
2003
36 days
2004
73 days
2005
24 days
2006
70 days
2007
41 days
2008
36 days
2009
29 days
2010
41 days
2011
46 days
2012
72 days
2013
51 days
2014
29 days
2015
49 days
2016
45 days
2017
41 days
2018
45 days
2019
32 days
2020
62 days
2021
40 days
2022
39 days
2023
43 days
2024
30 days
2025
38 days
2026
38 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
62 years with a frost
Across 62 years with a frost, the median last spring frost at Harlowton falls on 25 May and the median first autumn frost on 14 September, which leaves a median of 108 days between them.
In 1982 to 2025 the median growing season was 113 days. That is 8 days more than in 1950 to 1979.
Fitted over all years, the growing season changes by +2.4 days per decade at this station.
Frost dates and growing season at Harlowton
Measure
Median, all years
Earliest period (1950 to 1979)
Recent period (1982 to 2025)
Recent against earliest
Fitted trend
Last spring frost
25 May
30 May
25 May
5 days earlier
-1.2 days per decade
First autumn frost
14 September
13 September
18 September
5 days later
+1.2 days per decade
Growing days
108 days
105 days
113 days
8 days more
+2.4 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
57 years, 1950 to 2025
A day with at least 30.2 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 71.4 mm (2.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Harlowton: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
30.2 mm (1.2 in)
5 years
40.7 mm (1.6 in)
10 years
47.9 mm (1.9 in)
25 years
57.2 mm (2.3 in)
50 years
64.3 mm (2.5 in)
100 years
71.4 mm (2.8 in)
Longer than the 57 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, 57 years of values from 1950 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: 62.0 mm (2.4 in) in 1997; 60.5 mm (2.4 in) in 1975; 57.9 mm (2.3 in) in 1992.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Harlowton standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Harlowton 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.