Record envelope, standing records and threshold days for Port San Juan (USC00507738), Alaska, United States, with 47 years of record.
Key Facts for Port San Juan
Port San Juan (USC00507738) is a weather station in Alaska, United States at 60.05 latitude and -148.07 longitude, 12 m (40 ft) above sea level.
The station reports from 1980 to 2026, 47 years of record.
1,464 records set at Port San Juan still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Port San Juan set a daily record low minimum temperature of 7.2 C (45.0 F) on 30 July 2026.
About the Station
Location: Alaska, United States, 60.05 latitude, -148.07 longitude.
Elevation: 12 m (40 ft).
Period of record: 1980 to 2026, 47 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
26 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 Port San Juan. The lines show the 2026 daily maximum and minimum. 26 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Port San Juan, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
12.2 C (54.0 F)
-20.6 C (-5.1 F)
6.1 C (43.0 F)
-12.2 C (10.0 F)
Feb
10.0 C (50.0 F)
-18.3 C (-0.9 F)
6.7 C (44.1 F)
-12.8 C (9.0 F)
Mar
10.6 C (51.1 F)
-14.4 C (6.1 F)
2.2 C (36.0 F)
-12.2 C (10.0 F)
Apr
16.7 C (62.1 F)
-15.0 C (5.0 F)
8.3 C (46.9 F)
-6.7 C (19.9 F)
May
22.8 C (73.0 F)
-5.0 C (23.0 F)
12.2 C (54.0 F)
-0.6 C (30.9 F)
Jun
27.8 C (82.0 F)
-2.8 C (27.0 F)
23.9 C (75.0 F)
1.7 C (35.1 F)
Jul
30.0 C (86.0 F)
-1.1 C (30.0 F)
23.9 C (75.0 F)
5.0 C (41.0 F)
Aug
28.3 C (82.9 F)
-1.1 C (30.0 F)
n/a
n/a
Sep
18.9 C (66.0 F)
-12.2 C (10.0 F)
9.4 C (48.9 F)
5.6 C (42.1 F)
Oct
14.4 C (57.9 F)
-12.8 C (9.0 F)
n/a
n/a
Nov
11.1 C (52.0 F)
-16.7 C (1.9 F)
n/a
n/a
Dec
11.1 C (52.0 F)
-14.4 C (6.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Port San Juan still stand. 1985 holds the most, with 77.
Standing records at Port San Juan by the year they were set
Year set
Standing records
1980
30
1981
57
1982
34
1983
37
1984
32
1985
77
1986
33
1987
22
1988
17
1989
34
1990
50
1991
27
1992
52
1993
33
1994
35
1995
23
1996
34
1997
34
1998
34
1999
27
2000
21
2001
24
2002
63
2003
53
2004
36
2005
16
2006
18
2007
22
2008
27
2009
24
2010
26
2011
20
2012
29
2013
48
2014
44
2015
36
2016
47
2017
16
2018
20
2019
36
2020
9
2021
20
2022
8
2023
14
2024
14
2025
25
2026
26
All-Time Record Progression
4 new records
4 all-time records were set at Port San Juan between 19 March 2012 and 18 July 2016. Each dot is a new record.
When Port San Juan set new all-time records
Date
Kind
Detail
2012-03-19
Record snow depth
Record snow depth 177.8 cm (70.0 in)
2012-03-24
Record snow depth
Record snow depth 182.9 cm (72.0 in)
2012-09-20
Record daily precipitation
Record daily precipitation 214.6 mm (8.4 in)
2016-07-18
Record high maximum temperature
Record high maximum temperature 30.0 C (86.0 F)
Wettest Day of Each Month
Sep: 214.6 mm (8.4 in)
The wettest day on record for each calendar month at Port San Juan. The most was 214.6 mm (8.4 in) on 20 September 2012.
Record daily precipitation for each month at Port San Juan
Month
Record daily precipitation (mm)
Date
Jan
139.7 mm (5.5 in)
16 January 2026
Feb
99.3 mm (3.9 in)
4 February 2003
Mar
87.1 mm (3.4 in)
16 March 2019
Apr
106.9 mm (4.2 in)
10 April 2006
May
144.3 mm (5.7 in)
5 May 2025
Jun
90.7 mm (3.6 in)
18 June 2018
Jul
106.2 mm (4.2 in)
20 July 2026
Aug
139.2 mm (5.5 in)
26 August 1989
Sep
214.6 mm (8.4 in)
20 September 2012
Oct
180.6 mm (7.1 in)
9 October 2006
Nov
214.6 mm (8.4 in)
25 November 2018
Dec
99.6 mm (3.9 in)
26 December 2022
Period of Record Coverage
1980 to 2026
Complete yearUnder 90 percent of days
47 years of record at Port San Juan, 1980 to 2026. 12 years have data for under 90 percent of days and are left out of rankings: 1980, 1982, 1983, 1987, 1988, 1989, 1994, 1995 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 29 complete years at Port San Juan, 1981 to 2025. Blue stripes are years cooler than the station's own mean of 5.1 C (41.2 F); red stripes are warmer. The coolest year was 1990, at 3.7 C (38.7 F), and the warmest was 2019, at 6.5 C (43.7 F). The strongest colour marks a difference of 1.5 C (2.7 F).
Annual mean temperature at Port San Juan as warming stripes, 1981 to 2025
Year
Annual mean temperature
Difference from the station mean
1981
5.8 C
+0.66 C
1986
5.2 C
+0.10 C
1988
4.9 C
-0.23 C
1990
3.7 C
-1.36 C
1991
4.5 C
-0.60 C
1992
4.3 C
-0.80 C
1993
5.6 C
+0.49 C
1996
4.8 C
-0.30 C
1997
6.0 C
+0.90 C
2000
5.2 C
+0.14 C
2001
5.3 C
+0.19 C
2002
5.8 C
+0.66 C
2003
6.0 C
+0.86 C
2007
4.7 C
-0.39 C
2008
4.0 C
-1.14 C
2009
4.6 C
-0.46 C
2010
5.2 C
+0.11 C
2011
4.5 C
-0.60 C
2013
4.5 C
-0.64 C
2015
6.0 C
+0.87 C
2017
4.9 C
-0.22 C
2018
5.6 C
+0.52 C
2019
6.5 C
+1.40 C
2020
5.0 C
-0.13 C
2021
4.4 C
-0.73 C
2022
5.5 C
+0.39 C
2023
4.8 C
-0.27 C
2024
5.1 C
-0.05 C
2025
5.6 C
+0.54 C
This station does not have enough complete years (30 are needed) to fit a temperature trend.
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
1980 to 2026
Yearly extremes at Port San Juan: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
30.0 C (86.0 F)
2016
24.4 C (75.9 F)
47
Coldest night (TNn)
-20.6 C (-5.1 F)
1989
-13.3 C (8.1 F)
47
Wettest day (Rx1day)
214.6 mm (8.4 in)
2012
101.1 mm (4.0 in)
47
Wettest five days (Rx5day)
554.7 mm (21.8 in)
2012
229.4 mm (9.0 in)
47
Longest dry spell (CDD)
30 days
2019
14 days
47
Hottest day (TXx)
The hottest day of the year at Port San Juan, 1980 to 2026. The record is 30.0 C (86.0 F) in 2016, marked on the chart; the median year is 24.4 C (75.9 F).
Hottest day (TXx) at Port San Juan by year
Year
Hottest day (TXx)
1980
20.0 C (68.0 F)
1981
21.1 C (70.0 F)
1982
20.6 C (69.1 F)
1983
23.9 C (75.0 F)
1984
24.4 C (75.9 F)
1985
25.0 C (77.0 F)
1986
22.8 C (73.0 F)
1987
24.4 C (75.9 F)
1988
20.6 C (69.1 F)
1989
23.3 C (73.9 F)
1990
24.4 C (75.9 F)
1991
20.6 C (69.1 F)
1992
21.7 C (71.1 F)
1993
25.6 C (78.1 F)
1994
26.1 C (79.0 F)
1995
27.8 C (82.0 F)
1996
25.0 C (77.0 F)
1997
27.8 C (82.0 F)
1998
25.6 C (78.1 F)
1999
28.3 C (82.9 F)
2000
22.8 C (73.0 F)
2001
26.7 C (80.1 F)
2002
25.0 C (77.0 F)
2003
27.8 C (82.0 F)
2004
26.1 C (79.0 F)
2005
8.3 C (46.9 F)
2006
22.8 C (73.0 F)
2007
24.4 C (75.9 F)
2008
21.7 C (71.1 F)
2009
25.0 C (77.0 F)
2010
20.0 C (68.0 F)
2011
22.2 C (72.0 F)
2012
20.0 C (68.0 F)
2013
27.2 C (81.0 F)
2014
23.9 C (75.0 F)
2015
26.1 C (79.0 F)
2016
30.0 C (86.0 F)
2017
21.7 C (71.1 F)
2018
26.1 C (79.0 F)
2019
28.3 C (82.9 F)
2020
24.4 C (75.9 F)
2021
23.9 C (75.0 F)
2022
24.4 C (75.9 F)
2023
22.2 C (72.0 F)
2024
21.7 C (71.1 F)
2025
25.0 C (77.0 F)
2026
23.9 C (75.0 F)
Coldest night (TNn)
The coldest night of the year at Port San Juan, 1980 to 2026. The record is -20.6 C (-5.1 F) in 1989, marked on the chart; the median year is -13.3 C (8.1 F).
Coldest night (TNn) at Port San Juan by year
Year
Coldest night (TNn)
1980
-6.7 C (19.9 F)
1981
-11.1 C (12.0 F)
1982
-16.1 C (3.0 F)
1983
-16.7 C (1.9 F)
1984
-13.3 C (8.1 F)
1985
-16.7 C (1.9 F)
1986
-13.9 C (7.0 F)
1987
-14.4 C (6.1 F)
1988
-14.4 C (6.1 F)
1989
-20.6 C (-5.1 F)
1990
-16.1 C (3.0 F)
1991
-16.7 C (1.9 F)
1992
-14.4 C (6.1 F)
1993
-16.7 C (1.9 F)
1994
-14.4 C (6.1 F)
1995
-13.3 C (8.1 F)
1996
-13.3 C (8.1 F)
1997
-13.3 C (8.1 F)
1998
-13.9 C (7.0 F)
1999
-18.3 C (-0.9 F)
2000
-12.8 C (9.0 F)
2001
-11.7 C (10.9 F)
2002
-11.1 C (12.0 F)
2003
-13.3 C (8.1 F)
2004
-12.8 C (9.0 F)
2005
-11.1 C (12.0 F)
2006
-14.4 C (6.1 F)
2007
-15.0 C (5.0 F)
2008
-13.3 C (8.1 F)
2009
-14.4 C (6.1 F)
2010
-13.3 C (8.1 F)
2011
-13.9 C (7.0 F)
2012
-13.9 C (7.0 F)
2013
-15.0 C (5.0 F)
2014
-10.0 C (14.0 F)
2015
-10.0 C (14.0 F)
2016
-7.2 C (19.0 F)
2017
-11.7 C (10.9 F)
2018
-10.6 C (12.9 F)
2019
-11.7 C (10.9 F)
2020
-12.2 C (10.0 F)
2021
-12.2 C (10.0 F)
2022
-11.7 C (10.9 F)
2023
-11.7 C (10.9 F)
2024
-13.9 C (7.0 F)
2025
-11.7 C (10.9 F)
2026
-12.8 C (9.0 F)
Wettest day (Rx1day)
The wettest day of the year at Port San Juan, 1980 to 2026. The record is 214.6 mm (8.4 in) in 2012, marked on the chart; the median year is 101.1 mm (4.0 in).
Wettest day (Rx1day) at Port San Juan by year
Year
Wettest day (Rx1day)
1980
63.0 mm (2.5 in)
1981
79.8 mm (3.1 in)
1982
109.7 mm (4.3 in)
1983
99.8 mm (3.9 in)
1984
94.0 mm (3.7 in)
1985
85.3 mm (3.4 in)
1986
103.6 mm (4.1 in)
1987
121.2 mm (4.8 in)
1988
83.8 mm (3.3 in)
1989
139.2 mm (5.5 in)
1990
123.4 mm (4.9 in)
1991
64.0 mm (2.5 in)
1992
104.9 mm (4.1 in)
1993
101.1 mm (4.0 in)
1994
78.0 mm (3.1 in)
1995
88.9 mm (3.5 in)
1996
130.8 mm (5.1 in)
1997
106.7 mm (4.2 in)
1998
68.6 mm (2.7 in)
1999
105.4 mm (4.1 in)
2000
75.4 mm (3.0 in)
2001
97.0 mm (3.8 in)
2002
123.2 mm (4.9 in)
2003
100.3 mm (3.9 in)
2004
85.3 mm (3.4 in)
2005
77.5 mm (3.1 in)
2006
180.6 mm (7.1 in)
2007
85.1 mm (3.4 in)
2008
115.6 mm (4.6 in)
2009
87.1 mm (3.4 in)
2010
99.1 mm (3.9 in)
2011
90.4 mm (3.6 in)
2012
214.6 mm (8.4 in)
2013
95.5 mm (3.8 in)
2014
156.2 mm (6.1 in)
2015
121.4 mm (4.8 in)
2016
106.7 mm (4.2 in)
2017
95.5 mm (3.8 in)
2018
214.6 mm (8.4 in)
2019
87.6 mm (3.4 in)
2020
114.3 mm (4.5 in)
2021
114.8 mm (4.5 in)
2022
112.0 mm (4.4 in)
2023
97.0 mm (3.8 in)
2024
116.1 mm (4.6 in)
2025
144.3 mm (5.7 in)
2026
139.7 mm (5.5 in)
Wettest five days (Rx5day)
The wettest five days of the year at Port San Juan, 1980 to 2026. The record is 554.7 mm (21.8 in) in 2012, marked on the chart; the median year is 229.4 mm (9.0 in).
Wettest five days (Rx5day) at Port San Juan by year
Year
Wettest five days (Rx5day)
1980
190.5 mm (7.5 in)
1981
220.3 mm (8.7 in)
1982
219.7 mm (8.6 in)
1983
157.5 mm (6.2 in)
1984
211.7 mm (8.3 in)
1985
231.9 mm (9.1 in)
1986
263.8 mm (10.4 in)
1987
160.0 mm (6.3 in)
1988
163.6 mm (6.4 in)
1989
229.4 mm (9.0 in)
1990
212.2 mm (8.4 in)
1991
130.3 mm (5.1 in)
1992
238.6 mm (9.4 in)
1993
177.0 mm (7.0 in)
1994
157.5 mm (6.2 in)
1995
196.1 mm (7.7 in)
1996
154.7 mm (6.1 in)
1997
250.0 mm (9.8 in)
1998
179.1 mm (7.1 in)
1999
264.8 mm (10.4 in)
2000
193.6 mm (7.6 in)
2001
211.8 mm (8.3 in)
2002
293.9 mm (11.6 in)
2003
256.8 mm (10.1 in)
2004
184.5 mm (7.3 in)
2005
252.8 mm (10.0 in)
2006
328.9 mm (12.9 in)
2007
255.3 mm (10.1 in)
2008
235.2 mm (9.3 in)
2009
228.4 mm (9.0 in)
2010
263.5 mm (10.4 in)
2011
289.7 mm (11.4 in)
2012
554.7 mm (21.8 in)
2013
164.5 mm (6.5 in)
2014
317.9 mm (12.5 in)
2015
297.9 mm (11.7 in)
2016
249.5 mm (9.8 in)
2017
194.3 mm (7.6 in)
2018
312.4 mm (12.3 in)
2019
256.5 mm (10.1 in)
2020
276.6 mm (10.9 in)
2021
353.1 mm (13.9 in)
2022
202.2 mm (8.0 in)
2023
196.1 mm (7.7 in)
2024
235.7 mm (9.3 in)
2025
249.7 mm (9.8 in)
2026
214.4 mm (8.4 in)
Longest dry spell (CDD)
The longest dry spell of the year at Port San Juan, 1980 to 2026. The record is 30 days in 2019, marked on the chart; the median year is 14 days.
Longest dry spell (CDD) at Port San Juan by year
Year
Longest dry spell (CDD)
1980
11 days
1981
13 days
1982
18 days
1983
11 days
1984
12 days
1985
8 days
1986
10 days
1987
22 days
1988
9 days
1989
27 days
1990
15 days
1991
10 days
1992
15 days
1993
23 days
1994
22 days
1995
11 days
1996
18 days
1997
20 days
1998
12 days
1999
9 days
2000
14 days
2001
14 days
2002
22 days
2003
13 days
2004
18 days
2005
9 days
2006
22 days
2007
16 days
2008
12 days
2009
21 days
2010
11 days
2011
13 days
2012
11 days
2013
29 days
2014
15 days
2015
14 days
2016
11 days
2017
22 days
2018
18 days
2019
30 days
2020
11 days
2021
16 days
2022
13 days
2023
13 days
2024
13 days
2025
18 days
2026
21 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
29 years with a frost
Across 29 years with a frost, the median last spring frost at Port San Juan falls on 11 May and the median first autumn frost on 7 October, which leaves a median of 148 days between them.
Fitted over all years, the growing season changes by +3.9 days per decade at this station.
Frost dates and growing season at Port San Juan
Measure
Median, all years
Earliest period
Recent period (1981 to 2025)
Recent against earliest
Fitted trend
Last spring frost
11 May
n/a
11 May
n/a
-0.9 days per decade
First autumn frost
7 October
n/a
7 October
n/a
+3.0 days per decade
Growing days
148 days
n/a
148 days
n/a
+3.9 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, 1981 to 2025
A day with at least 100.4 mm (4.0 in) of rain is expected about once in 2 years. A day with at least 195.9 mm (7.7 in) of rain is expected about once in 100 years.
Rainfall return levels at Port San Juan: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
100.4 mm (4.0 in)
5 years
122.8 mm (4.8 in)
10 years
138.8 mm (5.5 in)
25 years
160.5 mm (6.3 in)
50 years
177.7 mm (7.0 in)
Longer than the 35 years of record
100 years
195.9 mm (7.7 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 1981 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: 214.6 mm (8.4 in) in 2018; 156.2 mm (6.1 in) in 2014; 144.3 mm (5.7 in) in 2025.
Download the Data
Data for Port San Juan standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Port San Juan 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.