Record envelope, standing records and threshold days for Cooper Lake Project (USC00502144), Alaska, United States, with 47 years of record.
Key Facts for Cooper Lake Project
Cooper Lake Project (USC00502144) is a weather station in Alaska, United States at 60.39 latitude and -149.67 longitude, 154 m (505 ft) above sea level.
The station reports from 1958 to 2004, 47 years of record.
1,464 records set at Cooper Lake Project still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Cooper Lake Project set a daily record low maximum temperature of -8.9 C (16.0 F) on 31 March 2004.
About the Station
Location: Alaska, United States, 60.39 latitude, -149.67 longitude.
Elevation: 154 m (505 ft).
Period of record: 1958 to 2004, 47 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
0 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 Cooper Lake Project. 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 Cooper Lake Project, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
9.4 C (48.9 F)
-31.7 C (-25.1 F)
n/a
n/a
Feb
10.6 C (51.1 F)
-32.2 C (-26.0 F)
n/a
n/a
Mar
10.6 C (51.1 F)
-31.7 C (-25.1 F)
n/a
n/a
Apr
17.8 C (64.0 F)
-21.1 C (-6.0 F)
n/a
n/a
May
23.9 C (75.0 F)
-9.4 C (15.1 F)
n/a
n/a
Jun
28.9 C (84.0 F)
-2.2 C (28.0 F)
n/a
n/a
Jul
30.6 C (87.1 F)
1.1 C (34.0 F)
n/a
n/a
Aug
28.3 C (82.9 F)
-5.0 C (23.0 F)
n/a
n/a
Sep
21.1 C (70.0 F)
-6.7 C (19.9 F)
n/a
n/a
Oct
17.2 C (63.0 F)
-15.0 C (5.0 F)
n/a
n/a
Nov
12.8 C (55.0 F)
-21.7 C (-7.1 F)
n/a
n/a
Dec
12.8 C (55.0 F)
-27.8 C (-18.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Cooper Lake Project still stand. 1971 holds the most, with 63.
Standing records at Cooper Lake Project by the year they were set
Year set
Standing records
1959
56
1960
31
1961
31
1962
32
1963
52
1964
41
1965
39
1966
46
1967
29
1968
35
1969
45
1970
35
1971
63
1972
45
1973
29
1974
26
1975
45
1976
16
1977
23
1978
18
1979
42
1980
33
1981
33
1982
21
1983
20
1984
28
1985
44
1986
36
1987
5
1988
12
1989
29
1990
36
1991
13
1992
37
1993
37
1994
19
1995
36
1996
38
1997
25
1998
13
1999
35
2000
17
2001
31
2002
52
2003
34
2004
1
All-Time Record Progression
11 new records
11 all-time records were set at Cooper Lake Project between 28 January 1989 and 28 November 2003. Each dot is a new record.
When Cooper Lake Project set new all-time records
Date
Kind
Detail
1989-01-28
Record low maximum temperature
Record low maximum temperature -25.6 C (-14.1 F)
1991-12-30
Record snow depth
Record snow depth 116.8 cm (46.0 in)
1992-02-28
Record snow depth
Record snow depth 121.9 cm (48.0 in)
1992-12-02
Record daily precipitation
Record daily precipitation 100.1 mm (3.9 in)
1993-07-19
Record high maximum temperature
Record high maximum temperature 30.6 C (87.1 F)
1994-08-12
Record high minimum temperature
Record high minimum temperature 15.0 C (59.0 F)
1998-12-29
Record daily snowfall
Record daily snowfall 57.2 cm (22.5 in)
1999-02-04
Record low minimum temperature
Record low minimum temperature -32.2 C (-26.0 F)
2000-01-31
Record snow depth
Record snow depth 132.1 cm (52.0 in)
2000-02-01
Record snow depth
Record snow depth 137.2 cm (54.0 in)
2003-11-28
Record daily precipitation
Record daily precipitation 101.6 mm (4.0 in)
Wettest Day of Each Month
Nov: 101.6 mm (4.0 in)
The wettest day on record for each calendar month at Cooper Lake Project. The most was 101.6 mm (4.0 in) on 28 November 2003.
Record daily precipitation for each month at Cooper Lake Project
Month
Record daily precipitation (mm)
Date
Jan
76.5 mm (3.0 in)
2 January 1963
Feb
76.7 mm (3.0 in)
14 February 1963
Mar
40.4 mm (1.6 in)
16 March 1995
Apr
50.8 mm (2.0 in)
12 April 1988
May
28.4 mm (1.1 in)
18 May 1977
Jun
39.9 mm (1.6 in)
9 June 1969
Jul
23.1 mm (0.9 in)
24 July 1995
Aug
88.6 mm (3.5 in)
21 August 1966
Sep
81.3 mm (3.2 in)
20 September 1995
Oct
76.7 mm (3.0 in)
11 October 1969
Nov
101.6 mm (4.0 in)
28 November 2003
Dec
100.1 mm (3.9 in)
2 December 1992
Period of Record Coverage
1958 to 2004
Complete yearUnder 90 percent of days
47 years of record at Cooper Lake Project, 1958 to 2004. 13 years have data for under 90 percent of days and are left out of rankings: 1958, 1961, 1977, 1985, 1986, 1987, 1988, 1993 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 36 complete years at Cooper Lake Project, 1959 to 2000. Blue stripes are years cooler than the station's own mean of 2.9 C (37.3 F); red stripes are warmer. The coolest year was 1971, at 0.7 C (33.3 F), and the warmest was 1993, at 4.9 C (40.8 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Cooper Lake Project as warming stripes, 1959 to 2000
Year
Annual mean temperature
Difference from the station mean
1959
1.8 C
-1.16 C
1962
2.9 C
-0.08 C
1963
3.8 C
+0.82 C
1964
2.4 C
-0.53 C
1965
2.2 C
-0.78 C
1966
1.6 C
-1.36 C
1967
2.6 C
-0.35 C
1968
2.8 C
-0.11 C
1969
3.3 C
+0.37 C
1970
3.0 C
+0.09 C
1971
0.7 C
-2.23 C
1972
0.9 C
-2.02 C
1973
1.3 C
-1.65 C
1974
2.9 C
-0.02 C
1975
1.5 C
-1.45 C
1976
3.1 C
+0.14 C
1977
4.3 C
+1.31 C
1978
4.7 C
+1.76 C
1979
3.8 C
+0.88 C
1980
2.9 C
-0.06 C
1981
4.6 C
+1.62 C
1982
2.3 C
-0.60 C
1983
4.2 C
+1.27 C
1984
4.2 C
+1.25 C
1986
4.0 C
+1.09 C
1989
2.8 C
-0.19 C
1990
2.2 C
-0.75 C
1991
3.6 C
+0.66 C
1992
2.7 C
-0.27 C
1993
4.9 C
+1.97 C
1994
3.6 C
+0.62 C
1995
3.0 C
+0.03 C
1997
2.5 C
-0.46 C
1998
3.2 C
+0.27 C
1999
1.0 C
-1.91 C
2000
4.6 C
+1.66 C
The fitted trend in annual mean temperature here over 1959 to 2000 is 0.27 C (-0.04 to 0.59) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.5 F (-0.1 to 1.1) per decade. The slope is a straight line fitted to 36 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Cooper Lake Project
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.27 C (-0.04 to 0.59) per decade
0.5 F (-0.1 to 1.1) per decade
1959 to 2000
36
Not clearly different from zero
Mean daily maximum
0.3 C (0.1 to 0.6) per decade
0.6 F (0.1 to 1.1) per decade
1959 to 2000
36
Rise
Mean daily minimum
0.2 C (-0.2 to 0.6) per decade
0.4 F (-0.3 to 1.1) per decade
1959 to 2000
36
Not clearly different from zero
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
1958 to 2004
Yearly extremes at Cooper Lake Project: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
30.6 C (87.1 F)
1993
26.1 C (79.0 F)
47
Coldest night (TNn)
-32.2 C (-26.0 F)
1999
-25.6 C (-14.1 F)
47
Wettest day (Rx1day)
101.6 mm (4.0 in)
2003
53.2 mm (2.1 in)
46
Wettest five days (Rx5day)
197.5 mm (7.8 in)
2002
95.9 mm (3.8 in)
46
Longest dry spell (CDD)
79 days
2001
29 days
46
Hottest day (TXx)
The hottest day of the year at Cooper Lake Project, 1958 to 2004. The record is 30.6 C (87.1 F) in 1993, marked on the chart; the median year is 26.1 C (79.0 F).
Hottest day (TXx) at Cooper Lake Project by year
Year
Hottest day (TXx)
1958
5.6 C (42.1 F)
1959
27.8 C (82.0 F)
1960
22.2 C (72.0 F)
1961
24.4 C (75.9 F)
1962
27.2 C (81.0 F)
1963
24.4 C (75.9 F)
1964
23.9 C (75.0 F)
1965
22.2 C (72.0 F)
1966
27.8 C (82.0 F)
1967
25.6 C (78.1 F)
1968
28.3 C (82.9 F)
1969
28.9 C (84.0 F)
1970
27.2 C (81.0 F)
1971
27.8 C (82.0 F)
1972
26.7 C (80.1 F)
1973
23.3 C (73.9 F)
1974
26.1 C (79.0 F)
1975
26.7 C (80.1 F)
1976
27.2 C (81.0 F)
1977
27.8 C (82.0 F)
1978
26.7 C (80.1 F)
1979
26.7 C (80.1 F)
1980
23.9 C (75.0 F)
1981
23.3 C (73.9 F)
1982
24.4 C (75.9 F)
1983
23.9 C (75.0 F)
1984
25.0 C (77.0 F)
1985
25.6 C (78.1 F)
1986
26.7 C (80.1 F)
1987
25.0 C (77.0 F)
1988
23.9 C (75.0 F)
1989
28.3 C (82.9 F)
1990
27.2 C (81.0 F)
1991
27.2 C (81.0 F)
1992
25.0 C (77.0 F)
1993
30.6 C (87.1 F)
1994
25.6 C (78.1 F)
1995
27.2 C (81.0 F)
1996
27.2 C (81.0 F)
1997
28.9 C (84.0 F)
1998
26.1 C (79.0 F)
1999
28.3 C (82.9 F)
2000
25.6 C (78.1 F)
2001
24.4 C (75.9 F)
2002
25.0 C (77.0 F)
2003
25.6 C (78.1 F)
2004
7.2 C (45.0 F)
Coldest night (TNn)
The coldest night of the year at Cooper Lake Project, 1958 to 2004. The record is -32.2 C (-26.0 F) in 1999, marked on the chart; the median year is -25.6 C (-14.1 F).
Coldest night (TNn) at Cooper Lake Project by year
Year
Coldest night (TNn)
1958
-17.8 C (0.0 F)
1959
-26.7 C (-16.1 F)
1960
-25.6 C (-14.1 F)
1961
-27.8 C (-18.0 F)
1962
-27.8 C (-18.0 F)
1963
-23.3 C (-9.9 F)
1964
-26.1 C (-15.0 F)
1965
-25.0 C (-13.0 F)
1966
-28.9 C (-20.0 F)
1967
-27.2 C (-17.0 F)
1968
-29.4 C (-20.9 F)
1969
-26.7 C (-16.1 F)
1970
-22.2 C (-8.0 F)
1971
-31.7 C (-25.1 F)
1972
-31.7 C (-25.1 F)
1973
-31.1 C (-24.0 F)
1974
-29.4 C (-20.9 F)
1975
-26.1 C (-15.0 F)
1976
-25.0 C (-13.0 F)
1977
-19.4 C (-2.9 F)
1978
-16.1 C (3.0 F)
1979
-22.2 C (-8.0 F)
1980
-24.4 C (-11.9 F)
1981
-16.7 C (1.9 F)
1982
-23.9 C (-11.0 F)
1983
-21.7 C (-7.1 F)
1984
-22.2 C (-8.0 F)
1985
-21.1 C (-6.0 F)
1986
-25.0 C (-13.0 F)
1987
-17.8 C (0.0 F)
1988
-18.9 C (-2.0 F)
1989
-31.7 C (-25.1 F)
1990
-28.9 C (-20.0 F)
1991
-26.7 C (-16.1 F)
1992
-26.7 C (-16.1 F)
1993
-25.6 C (-14.1 F)
1994
-26.7 C (-16.1 F)
1995
-27.2 C (-17.0 F)
1996
-27.8 C (-18.0 F)
1997
-29.4 C (-20.9 F)
1998
-21.1 C (-6.0 F)
1999
-32.2 C (-26.0 F)
2000
-20.0 C (-4.0 F)
2001
-22.2 C (-8.0 F)
2002
-20.6 C (-5.1 F)
2003
-19.4 C (-2.9 F)
2004
-25.6 C (-14.1 F)
Wettest day (Rx1day)
The wettest day of the year at Cooper Lake Project, 1958 to 2004. The record is 101.6 mm (4.0 in) in 2003, marked on the chart; the median year is 53.2 mm (2.1 in).
Wettest day (Rx1day) at Cooper Lake Project by year
Year
Wettest day (Rx1day)
1958
n/a
1959
35.1 mm (1.4 in)
1960
33.5 mm (1.3 in)
1961
66.3 mm (2.6 in)
1962
34.3 mm (1.4 in)
1963
76.7 mm (3.0 in)
1964
53.1 mm (2.1 in)
1965
32.8 mm (1.3 in)
1966
88.6 mm (3.5 in)
1967
70.6 mm (2.8 in)
1968
46.2 mm (1.8 in)
1969
76.7 mm (3.0 in)
1970
45.7 mm (1.8 in)
1971
27.4 mm (1.1 in)
1972
32.0 mm (1.3 in)
1973
24.1 mm (0.9 in)
1974
25.9 mm (1.0 in)
1975
46.7 mm (1.8 in)
1976
61.0 mm (2.4 in)
1977
58.2 mm (2.3 in)
1978
54.9 mm (2.2 in)
1979
64.8 mm (2.6 in)
1980
80.0 mm (3.1 in)
1981
58.7 mm (2.3 in)
1982
42.9 mm (1.7 in)
1983
35.6 mm (1.4 in)
1984
52.3 mm (2.1 in)
1985
75.7 mm (3.0 in)
1986
53.3 mm (2.1 in)
1987
59.9 mm (2.4 in)
1988
50.8 mm (2.0 in)
1989
59.7 mm (2.4 in)
1990
57.2 mm (2.3 in)
1991
41.7 mm (1.6 in)
1992
100.1 mm (3.9 in)
1993
45.7 mm (1.8 in)
1994
32.5 mm (1.3 in)
1995
81.3 mm (3.2 in)
1996
24.9 mm (1.0 in)
1997
36.6 mm (1.4 in)
1998
62.2 mm (2.4 in)
1999
90.4 mm (3.6 in)
2000
50.8 mm (2.0 in)
2001
68.1 mm (2.7 in)
2002
95.3 mm (3.8 in)
2003
101.6 mm (4.0 in)
2004
0.0 mm (0.00 in)
Wettest five days (Rx5day)
The wettest five days of the year at Cooper Lake Project, 1958 to 2004. The record is 197.5 mm (7.8 in) in 2002, marked on the chart; the median year is 95.9 mm (3.8 in).
Wettest five days (Rx5day) at Cooper Lake Project by year
Year
Wettest five days (Rx5day)
1958
n/a
1959
43.2 mm (1.7 in)
1960
95.2 mm (3.7 in)
1961
110.0 mm (4.3 in)
1962
57.5 mm (2.3 in)
1963
130.6 mm (5.1 in)
1964
105.5 mm (4.2 in)
1965
54.1 mm (2.1 in)
1966
134.8 mm (5.3 in)
1967
123.7 mm (4.9 in)
1968
92.7 mm (3.6 in)
1969
142.7 mm (5.6 in)
1970
136.1 mm (5.4 in)
1971
45.2 mm (1.8 in)
1972
65.6 mm (2.6 in)
1973
42.9 mm (1.7 in)
1974
70.8 mm (2.8 in)
1975
67.5 mm (2.7 in)
1976
178.9 mm (7.0 in)
1977
93.0 mm (3.7 in)
1978
94.1 mm (3.7 in)
1979
96.6 mm (3.8 in)
1980
146.1 mm (5.8 in)
1981
118.9 mm (4.7 in)
1982
102.3 mm (4.0 in)
1983
76.5 mm (3.0 in)
1984
126.5 mm (5.0 in)
1985
112.8 mm (4.4 in)
1986
84.9 mm (3.3 in)
1987
124.2 mm (4.9 in)
1988
94.7 mm (3.7 in)
1989
148.6 mm (5.9 in)
1990
96.6 mm (3.8 in)
1991
90.2 mm (3.6 in)
1992
101.9 mm (4.0 in)
1993
90.5 mm (3.6 in)
1994
62.7 mm (2.5 in)
1995
180.9 mm (7.1 in)
1996
51.6 mm (2.0 in)
1997
68.9 mm (2.7 in)
1998
75.9 mm (3.0 in)
1999
159.3 mm (6.3 in)
2000
100.9 mm (4.0 in)
2001
168.2 mm (6.6 in)
2002
197.5 mm (7.8 in)
2003
28.5 mm (1.1 in)
2004
0.0 mm (0.00 in)
Longest dry spell (CDD)
The longest dry spell of the year at Cooper Lake Project, 1958 to 2004. The record is 79 days in 2001, marked on the chart; the median year is 29 days.
Longest dry spell (CDD) at Cooper Lake Project by year
Year
Longest dry spell (CDD)
1958
n/a
1959
11 days
1960
29 days
1961
18 days
1962
16 days
1963
15 days
1964
17 days
1965
26 days
1966
20 days
1967
25 days
1968
33 days
1969
26 days
1970
17 days
1971
26 days
1972
33 days
1973
20 days
1974
29 days
1975
32 days
1976
19 days
1977
26 days
1978
38 days
1979
29 days
1980
33 days
1981
35 days
1982
29 days
1983
43 days
1984
28 days
1985
27 days
1986
26 days
1987
13 days
1988
31 days
1989
58 days
1990
26 days
1991
26 days
1992
58 days
1993
37 days
1994
21 days
1995
33 days
1996
34 days
1997
22 days
1998
35 days
1999
41 days
2000
69 days
2001
79 days
2002
33 days
2003
44 days
2004
31 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
36 years with a frost
Across 36 years with a frost, the median last spring frost at Cooper Lake Project falls on 18 May and the median first autumn frost on 26 September, which leaves a median of 135 days between them.
Fitted over all years, the growing season changes by +2.8 days per decade at this station.
Frost dates and growing season at Cooper Lake Project
Measure
Median, all years
Earliest period
Recent period (1967 to 2000)
Recent against earliest
Fitted trend
Last spring frost
18 May
n/a
18 May
n/a
-2.3 days per decade
First autumn frost
26 September
n/a
26 September
n/a
+0.4 days per decade
Growing days
135 days
n/a
136 days
n/a
+2.8 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
35 years, 1960 to 2001
A day with at least 51.6 mm (2.0 in) of rain is expected about once in 2 years. A day with at least 114.3 mm (4.5 in) of rain is expected about once in 100 years.
Rainfall return levels at Cooper Lake Project: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
51.6 mm (2.0 in)
5 years
71.2 mm (2.8 in)
10 years
83.0 mm (3.3 in)
25 years
96.6 mm (3.8 in)
50 years
105.8 mm (4.2 in)
Longer than the 35 years of record
100 years
114.3 mm (4.5 in)
Longer than the 35 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, 35 years of values from 1960 to 2001.
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: 100.1 mm (3.9 in) in 1992; 90.4 mm (3.6 in) in 1999; 88.6 mm (3.5 in) in 1966.
Download the Data
Data for Cooper Lake Project standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Cooper Lake Project 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.