Record envelope, standing records and threshold days for Summit WSO AP (USW00026414), Alaska, United States, with 72 years of record.
Key Facts for Summit WSO AP
Summit WSO AP (USW00026414) is a weather station in Alaska, United States at 63.33 latitude and -149.13 longitude, 735 m (2,411 ft) above sea level.
The station reports from 1905 to 1976, 72 years of record.
1,464 records set at Summit WSO AP still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Summit WSO AP set a daily record high maximum temperature of 13.3 C (55.9 F) on 26 September 1976.
About the Station
Location: Alaska, United States, 63.33 latitude, -149.13 longitude.
Elevation: 735 m (2,411 ft).
Period of record: 1905 to 1976, 72 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 Summit WSO AP. 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 Summit WSO AP, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
8.3 C (46.9 F)
-45.0 C (-49.0 F)
n/a
n/a
Feb
12.2 C (54.0 F)
-48.3 C (-54.9 F)
n/a
n/a
Mar
9.4 C (48.9 F)
-41.1 C (-42.0 F)
n/a
n/a
Apr
13.9 C (57.0 F)
-34.4 C (-29.9 F)
n/a
n/a
May
25.0 C (77.0 F)
-25.6 C (-14.1 F)
n/a
n/a
Jun
31.7 C (89.1 F)
-3.9 C (25.0 F)
n/a
n/a
Jul
27.2 C (81.0 F)
-3.9 C (25.0 F)
n/a
n/a
Aug
36.1 C (97.0 F)
-6.7 C (19.9 F)
n/a
n/a
Sep
23.9 C (75.0 F)
-14.4 C (6.1 F)
n/a
n/a
Oct
15.0 C (59.0 F)
-27.8 C (-18.0 F)
n/a
n/a
Nov
7.2 C (45.0 F)
-35.6 C (-32.1 F)
n/a
n/a
Dec
5.6 C (42.1 F)
-41.7 C (-43.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Summit WSO AP still stand. 1907 holds the most, with 102.
Standing records at Summit WSO AP by the year they were set
Year set
Standing records
1905
25
1906
83
1907
102
1941
51
1942
51
1943
40
1944
35
1945
41
1946
31
1947
56
1948
36
1949
25
1950
10
1951
30
1952
41
1953
31
1954
19
1955
38
1956
48
1957
46
1958
32
1959
21
1960
36
1961
50
1962
30
1963
51
1964
42
1965
50
1966
23
1967
20
1968
26
1969
59
1970
38
1971
40
1972
25
1973
15
1974
30
1975
27
1976
10
Wettest Day of Each Month
Jun: 56.4 mm (2.2 in)
The wettest day on record for each calendar month at Summit WSO AP. The most was 56.4 mm (2.2 in) on 29 June 1967.
Record daily precipitation for each month at Summit WSO AP
Month
Record daily precipitation (mm)
Date
Jan
26.2 mm (1.0 in)
19 January 1976
Feb
27.7 mm (1.1 in)
21 February 1943
Mar
36.3 mm (1.4 in)
30 March 1946
Apr
24.6 mm (1.0 in)
23 April 1963
May
48.3 mm (1.9 in)
8 May 1976
Jun
56.4 mm (2.2 in)
29 June 1967
Jul
49.5 mm (1.9 in)
20 July 1948
Aug
47.0 mm (1.9 in)
21 August 1944
Sep
52.6 mm (2.1 in)
8 September 1944
Oct
31.5 mm (1.2 in)
6 October 1963
Nov
33.0 mm (1.3 in)
18 November 1964
Dec
27.7 mm (1.1 in)
29 December 1967
Period of Record Coverage
1905 to 1976
Complete yearUnder 90 percent of days
39 years of record at Summit WSO AP, 1905 to 1976. 7 years have data for under 90 percent of days and are left out of rankings: 1905, 1906, 1907, 1941, 1949, 1950, 1976.
Cooler than the station meanWarmer than the station mean
One stripe for each of 31 complete years at Summit WSO AP, 1942 to 1975. Blue stripes are years cooler than the station's own mean of -3.8 C (25.1 F); red stripes are warmer. The coolest year was 1956, at -5.7 C (21.7 F), and the warmest was 1957, at -1.8 C (28.8 F). The strongest colour marks a difference of 2.1 C (3.8 F).
Annual mean temperature at Summit WSO AP as warming stripes, 1942 to 1975
Year
Annual mean temperature
Difference from the station mean
1942
-2.8 C
+1.01 C
1943
-2.1 C
+1.74 C
1945
-4.0 C
-0.19 C
1946
-3.9 C
-0.14 C
1947
-2.8 C
+1.02 C
1948
-5.3 C
-1.52 C
1951
-4.0 C
-0.23 C
1952
-3.4 C
+0.41 C
1953
-3.0 C
+0.82 C
1954
-3.8 C
+0.03 C
1955
-4.9 C
-1.05 C
1956
-5.7 C
-1.89 C
1957
-1.8 C
+2.01 C
1958
-2.9 C
+0.87 C
1959
-3.9 C
-0.08 C
1960
-2.5 C
+1.28 C
1961
-4.6 C
-0.79 C
1962
-3.2 C
+0.58 C
1963
-3.0 C
+0.81 C
1964
-4.7 C
-0.85 C
1965
-4.3 C
-0.47 C
1966
-4.6 C
-0.83 C
1967
-3.1 C
+0.68 C
1968
-3.8 C
-0.03 C
1969
-2.2 C
+1.64 C
1970
-3.9 C
-0.08 C
1971
-5.7 C
-1.85 C
1972
-5.2 C
-1.44 C
1973
-4.4 C
-0.62 C
1974
-3.8 C
-0.01 C
1975
-4.6 C
-0.84 C
The fitted trend in annual mean temperature here over 1942 to 1975 is -0.3 C (-0.7 to 0.1) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.6 F (-1.2 to 0.1) per decade. The slope is a straight line fitted to 31 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Summit WSO AP
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.3 C (-0.7 to 0.1) per decade
-0.6 F (-1.2 to 0.1) per decade
1942 to 1975
31
Not clearly different from zero
Mean daily maximum
-0.4 C (-0.8 to 0.1) per decade
-0.7 F (-1.5 to 0.1) per decade
1942 to 1975
31
Not clearly different from zero
Mean daily minimum
-0.2 C (-0.6 to 0.1) per decade
-0.4 F (-1.1 to 0.3) per decade
1942 to 1975
31
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
1905 to 1976
Yearly extremes at Summit WSO AP: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
36.1 C (97.0 F)
1905
25.6 C (78.1 F)
39
Coldest night (TNn)
-48.3 C (-54.9 F)
1907
-36.7 C (-34.1 F)
39
Wettest day (Rx1day)
56.4 mm (2.2 in)
1967
30.5 mm (1.2 in)
39
Wettest five days (Rx5day)
109.5 mm (4.3 in)
1955
52.3 mm (2.1 in)
39
Longest dry spell (CDD)
60 days
1950
33 days
39
Hottest day (TXx)
The hottest day of the year at Summit WSO AP, 1905 to 1976. The record is 36.1 C (97.0 F) in 1905, marked on the chart; the median year is 25.6 C (78.1 F).
Hottest day (TXx) at Summit WSO AP by year
Year
Hottest day (TXx)
1905
36.1 C (97.0 F)
1906
26.7 C (80.1 F)
1907
26.7 C (80.1 F)
1941
22.2 C (72.0 F)
1942
25.0 C (77.0 F)
1943
25.0 C (77.0 F)
1944
25.6 C (78.1 F)
1945
21.7 C (71.1 F)
1946
25.6 C (78.1 F)
1947
25.6 C (78.1 F)
1948
26.7 C (80.1 F)
1949
22.8 C (73.0 F)
1950
24.4 C (75.9 F)
1951
25.6 C (78.1 F)
1952
26.1 C (79.0 F)
1953
27.2 C (81.0 F)
1954
21.7 C (71.1 F)
1955
27.2 C (81.0 F)
1956
26.7 C (80.1 F)
1957
26.7 C (80.1 F)
1958
25.0 C (77.0 F)
1959
25.6 C (78.1 F)
1960
24.4 C (75.9 F)
1961
31.7 C (89.1 F)
1962
23.9 C (75.0 F)
1963
23.9 C (75.0 F)
1964
22.8 C (73.0 F)
1965
22.8 C (73.0 F)
1966
23.3 C (73.9 F)
1967
25.6 C (78.1 F)
1968
27.2 C (81.0 F)
1969
28.9 C (84.0 F)
1970
23.3 C (73.9 F)
1971
27.2 C (81.0 F)
1972
25.6 C (78.1 F)
1973
21.1 C (70.0 F)
1974
23.3 C (73.9 F)
1975
26.1 C (79.0 F)
1976
25.6 C (78.1 F)
Coldest night (TNn)
The coldest night of the year at Summit WSO AP, 1905 to 1976. The record is -48.3 C (-54.9 F) in 1907, marked on the chart; the median year is -36.7 C (-34.1 F).
Coldest night (TNn) at Summit WSO AP by year
Year
Coldest night (TNn)
1905
-38.3 C (-36.9 F)
1906
-45.0 C (-49.0 F)
1907
-48.3 C (-54.9 F)
1941
-34.4 C (-29.9 F)
1942
-35.6 C (-32.1 F)
1943
-37.2 C (-35.0 F)
1944
-37.2 C (-35.0 F)
1945
-37.2 C (-35.0 F)
1946
-38.3 C (-36.9 F)
1947
-42.8 C (-45.0 F)
1948
-33.9 C (-29.0 F)
1949
-33.3 C (-27.9 F)
1950
-30.0 C (-22.0 F)
1951
-38.9 C (-38.0 F)
1952
-36.1 C (-33.0 F)
1953
-35.0 C (-31.0 F)
1954
-35.0 C (-31.0 F)
1955
-35.6 C (-32.1 F)
1956
-36.7 C (-34.1 F)
1957
-32.2 C (-26.0 F)
1958
-30.0 C (-22.0 F)
1959
-31.1 C (-24.0 F)
1960
-33.3 C (-27.9 F)
1961
-41.7 C (-43.1 F)
1962
-39.4 C (-38.9 F)
1963
-32.8 C (-27.0 F)
1964
-37.8 C (-36.0 F)
1965
-35.0 C (-31.0 F)
1966
-35.0 C (-31.0 F)
1967
-32.2 C (-26.0 F)
1968
-40.0 C (-40.0 F)
1969
-33.3 C (-27.9 F)
1970
-36.7 C (-34.1 F)
1971
-42.8 C (-45.0 F)
1972
-37.8 C (-36.0 F)
1973
-38.3 C (-36.9 F)
1974
-36.7 C (-34.1 F)
1975
-38.9 C (-38.0 F)
1976
-33.3 C (-27.9 F)
Wettest day (Rx1day)
The wettest day of the year at Summit WSO AP, 1905 to 1976. The record is 56.4 mm (2.2 in) in 1967, marked on the chart; the median year is 30.5 mm (1.2 in).
Wettest day (Rx1day) at Summit WSO AP by year
Year
Wettest day (Rx1day)
1905
23.6 mm (0.9 in)
1906
23.1 mm (0.9 in)
1907
27.9 mm (1.1 in)
1941
24.1 mm (0.9 in)
1942
44.2 mm (1.7 in)
1943
53.3 mm (2.1 in)
1944
52.6 mm (2.1 in)
1945
30.5 mm (1.2 in)
1946
36.3 mm (1.4 in)
1947
28.7 mm (1.1 in)
1948
49.5 mm (1.9 in)
1949
30.7 mm (1.2 in)
1950
24.1 mm (0.9 in)
1951
22.6 mm (0.9 in)
1952
45.7 mm (1.8 in)
1953
37.8 mm (1.5 in)
1954
21.6 mm (0.9 in)
1955
39.9 mm (1.6 in)
1956
34.8 mm (1.4 in)
1957
29.2 mm (1.1 in)
1958
30.0 mm (1.2 in)
1959
32.5 mm (1.3 in)
1960
18.3 mm (0.7 in)
1961
41.9 mm (1.6 in)
1962
26.2 mm (1.0 in)
1963
31.5 mm (1.2 in)
1964
33.0 mm (1.3 in)
1965
32.5 mm (1.3 in)
1966
35.1 mm (1.4 in)
1967
56.4 mm (2.2 in)
1968
9.7 mm (0.38 in)
1969
14.2 mm (0.6 in)
1970
30.5 mm (1.2 in)
1971
23.9 mm (0.9 in)
1972
24.1 mm (0.9 in)
1973
15.2 mm (0.6 in)
1974
36.8 mm (1.4 in)
1975
19.8 mm (0.8 in)
1976
48.3 mm (1.9 in)
Wettest five days (Rx5day)
The wettest five days of the year at Summit WSO AP, 1905 to 1976. The record is 109.5 mm (4.3 in) in 1955, marked on the chart; the median year is 52.3 mm (2.1 in).
Wettest five days (Rx5day) at Summit WSO AP by year
Year
Wettest five days (Rx5day)
1905
42.0 mm (1.7 in)
1906
52.3 mm (2.1 in)
1907
45.7 mm (1.8 in)
1941
31.3 mm (1.2 in)
1942
95.7 mm (3.8 in)
1943
78.8 mm (3.1 in)
1944
77.2 mm (3.0 in)
1945
63.0 mm (2.5 in)
1946
38.7 mm (1.5 in)
1947
51.9 mm (2.0 in)
1948
79.0 mm (3.1 in)
1949
63.7 mm (2.5 in)
1950
55.0 mm (2.2 in)
1951
43.0 mm (1.7 in)
1952
84.6 mm (3.3 in)
1953
47.5 mm (1.9 in)
1954
51.3 mm (2.0 in)
1955
109.5 mm (4.3 in)
1956
51.3 mm (2.0 in)
1957
46.0 mm (1.8 in)
1958
39.0 mm (1.5 in)
1959
51.3 mm (2.0 in)
1960
33.6 mm (1.3 in)
1961
62.9 mm (2.5 in)
1962
53.6 mm (2.1 in)
1963
56.9 mm (2.2 in)
1964
66.5 mm (2.6 in)
1965
55.4 mm (2.2 in)
1966
77.7 mm (3.1 in)
1967
72.4 mm (2.9 in)
1968
37.6 mm (1.5 in)
1969
31.8 mm (1.3 in)
1970
68.4 mm (2.7 in)
1971
33.8 mm (1.3 in)
1972
48.8 mm (1.9 in)
1973
40.7 mm (1.6 in)
1974
48.1 mm (1.9 in)
1975
55.8 mm (2.2 in)
1976
54.1 mm (2.1 in)
Longest dry spell (CDD)
The longest dry spell of the year at Summit WSO AP, 1905 to 1976. The record is 60 days in 1950, marked on the chart; the median year is 33 days.
Longest dry spell (CDD) at Summit WSO AP by year
Year
Longest dry spell (CDD)
1905
21 days
1906
31 days
1907
27 days
1941
22 days
1942
35 days
1943
22 days
1944
34 days
1945
16 days
1946
34 days
1947
32 days
1948
35 days
1949
39 days
1950
60 days
1951
33 days
1952
15 days
1953
30 days
1954
48 days
1955
37 days
1956
29 days
1957
43 days
1958
36 days
1959
25 days
1960
35 days
1961
21 days
1962
35 days
1963
45 days
1964
24 days
1965
33 days
1966
29 days
1967
37 days
1968
36 days
1969
27 days
1970
23 days
1971
34 days
1972
43 days
1973
29 days
1974
23 days
1975
34 days
1976
24 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
31 years with a frost
Across 31 years with a frost, the median last spring frost at Summit WSO AP falls on 5 June and the median first autumn frost on 24 August, which leaves a median of 78 days between them.
Fitted over all years, the growing season changes by -1.0 days per decade at this station.
Frost dates and growing season at Summit WSO AP
Measure
Median, all years
Earliest period
Recent period (1943 to 1975)
Recent against earliest
Fitted trend
Last spring frost
5 June
n/a
5 June
n/a
+1.5 days per decade
First autumn frost
24 August
n/a
25 August
n/a
+0.5 days per decade
Growing days
78 days
n/a
79 days
n/a
-1.0 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
34 years, 1942 to 1975
A day with at least 31.4 mm (1.2 in) of rain is expected about once in 2 years. A day with at least 61.6 mm (2.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Summit WSO AP: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
31.4 mm (1.2 in)
5 years
41.7 mm (1.6 in)
10 years
47.5 mm (1.9 in)
25 years
53.9 mm (2.1 in)
50 years
58.0 mm (2.3 in)
Longer than the 34 years of record
100 years
61.6 mm (2.4 in)
Longer than the 34 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, 34 years of values from 1942 to 1975.
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: 56.4 mm (2.2 in) in 1967; 53.3 mm (2.1 in) in 1943; 52.6 mm (2.1 in) in 1944.
Download the Data
Data for Summit WSO AP standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Summit WSO AP 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 2026-10-15 (15 October 2026). Records are computed by this site and are not official.