Iliamna AP Weather Records (USW00025506)

Record envelope, standing records and threshold days for Iliamna AP (USW00025506), Alaska, United States, with 107 years of record.

Key Facts for Iliamna AP

Iliamna AP (USW00025506) is a weather station in Alaska, United States at 59.75 latitude and -154.91 longitude, 46 m (152 ft) above sea level.
The station reports from 1920 to 2026, 107 years of record.
1,464 records set at Iliamna AP still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Iliamna AP set a daily record precipitation of 33.0 mm (1.3 in) on 16 August 2026.

About the Station

Location: Alaska, United States, 59.75 latitude, -154.91 longitude.
Elevation: 46 m (152 ft).
Period of record: 1920 to 2026, 107 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.

Daily Record Envelope and 2026

9 days at or beyond a record

The band shows the record high and record low for each calendar day at Iliamna AP. The lines show the 2026 daily maximum and minimum. 9 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.

Daily record high and record low at Iliamna AP, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	13.9 C (57.0 F)	-43.9 C (-47.0 F)	5.0 C (41.0 F)	-32.2 C (-26.0 F)
Feb	10.0 C (50.0 F)	-43.3 C (-45.9 F)	7.2 C (45.0 F)	-31.7 C (-25.1 F)
Mar	11.1 C (52.0 F)	-34.4 C (-29.9 F)	2.2 C (36.0 F)	-31.1 C (-24.0 F)
Apr	19.4 C (66.9 F)	-34.4 C (-29.9 F)	7.8 C (46.0 F)	-16.1 C (3.0 F)
May	26.7 C (80.1 F)	-15.6 C (3.9 F)	12.8 C (55.0 F)	-3.3 C (26.1 F)
Jun	32.8 C (91.0 F)	-2.2 C (28.0 F)	27.8 C (82.0 F)	2.2 C (36.0 F)
Jul	30.0 C (86.0 F)	-1.1 C (30.0 F)	23.9 C (75.0 F)	4.4 C (39.9 F)
Aug	28.3 C (82.9 F)	-5.6 C (21.9 F)	21.7 C (71.1 F)	5.6 C (42.1 F)
Sep	23.9 C (75.0 F)	-6.7 C (19.9 F)	16.7 C (62.1 F)	-1.1 C (30.0 F)
Oct	18.9 C (66.0 F)	-20.0 C (-4.0 F)	11.1 C (52.0 F)	1.1 C (34.0 F)
Nov	11.1 C (52.0 F)	-28.9 C (-20.0 F)	n/a	n/a
Dec	9.4 C (48.9 F)	-35.0 C (-31.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at Iliamna AP still stand. 1921 holds the most, with 82.

Standing records at Iliamna AP by the year they were set
Year set	Standing records
1920	15
1921	82
1922	58
1941	7
1942	31
1943	14
1944	12
1945	17
1946	8
1947	41
1948	12
1949	23
1950	9
1951	12
1952	13
1953	17
1954	21
1955	18
1956	55
1957	19
1958	11
1959	7
1960	7
1961	22
1962	10
1963	25
1964	24
1965	23
1966	20
1967	5
1968	16
1969	11
1970	11
1971	25
1972	1
1973	2
1975	13
1976	10
1977	17
1978	3
1979	8
1980	11
1981	14
1982	16
1983	10
1984	21
1985	39
1986	17
1987	12
1988	10
1989	13
1990	11
1991	8
1992	6
1993	26
1994	14
1995	28
1996	13
1997	18
1998	9
1999	5
2000	10
2001	7
2002	34
2003	25
2004	14
2005	8
2006	6
2007	12
2008	4
2009	20
2010	3
2011	1
2012	6
2013	23
2014	35
2015	34
2016	36
2017	6
2018	16
2019	53
2020	8
2021	9
2022	4
2023	7
2024	10
2025	12
2026	5

All-Time Record Progression

5 new records

5 all-time records were set at Iliamna AP between 22 January 1968 and 27 June 1997. Each dot is a new record.

When Iliamna AP set new all-time records
Date	Kind	Detail
1968-01-22	Record daily snowfall	Record daily snowfall 35.6 cm (14.0 in)
1971-12-17	Record daily snowfall	Record daily snowfall 50.8 cm (20.0 in)
1984-08-25	Record daily precipitation	Record daily precipitation 67.8 mm (2.7 in)
1985-08-07	Record daily precipitation	Record daily precipitation 88.9 mm (3.5 in)
1997-06-27	Record high minimum temperature	Record high minimum temperature 16.1 C (61.0 F)

Wettest Day of Each Month

Aug: 88.9 mm (3.5 in)

The wettest day on record for each calendar month at Iliamna AP. The most was 88.9 mm (3.5 in) on 7 August 1985.

Record daily precipitation for each month at Iliamna AP
Month	Record daily precipitation (mm)	Date
Jan	55.4 mm (2.2 in)	11 January 1957
Feb	45.7 mm (1.8 in)	4 February 1923
Mar	37.6 mm (1.5 in)	30 March 1946
Apr	38.1 mm (1.5 in)	9 April 1921
May	52.8 mm (2.1 in)	30 May 2014
Jun	52.8 mm (2.1 in)	13 June 1985
Jul	50.8 mm (2.0 in)	18 July 1922
Aug	88.9 mm (3.5 in)	7 August 1985
Sep	75.2 mm (3.0 in)	27 September 2015
Oct	62.0 mm (2.4 in)	14 October 1958
Nov	45.5 mm (1.8 in)	8 November 1983
Dec	58.4 mm (2.3 in)	4 December 1943

Period of Record Coverage

1920 to 2026

90 years of record at Iliamna AP, 1920 to 2026. 14 years have data for under 90 percent of days and are left out of rankings: 1920, 1921, 1923, 1939, 1941, 1942, 1970, 1971 and others.

Days with data per year at Iliamna AP
Year	Days with data	Share of year	Complete
1920	169	46%	No
1921	301	82%	No
1922	332	91%	Yes
1923	59	16%	No
1939	19	5%	No
1941	269	74%	No
1942	303	83%	No
1943	361	99%	Yes
1944	365	100%	Yes
1945	365	100%	Yes
1946	361	99%	Yes
1947	365	100%	Yes
1948	366	100%	Yes
1949	365	100%	Yes
1950	365	100%	Yes
1951	365	100%	Yes
1952	366	100%	Yes
1953	365	100%	Yes
1954	365	100%	Yes
1955	365	100%	Yes
1956	366	100%	Yes
1957	365	100%	Yes
1958	365	100%	Yes
1959	365	100%	Yes
1960	366	100%	Yes
1961	365	100%	Yes
1962	364	100%	Yes
1963	365	100%	Yes
1964	366	100%	Yes
1965	365	100%	Yes
1966	363	99%	Yes
1967	364	100%	Yes
1968	366	100%	Yes
1969	365	100%	Yes
1970	288	79%	No
1971	219	60%	No
1972	43	12%	No
1973	109	30%	No
1975	183	50%	No
1976	334	91%	Yes
1977	365	100%	Yes
1978	365	100%	Yes
1979	363	99%	Yes
1980	366	100%	Yes
1981	365	100%	Yes
1982	365	100%	Yes
1983	363	99%	Yes
1984	365	100%	Yes
1985	365	100%	Yes
1986	356	98%	Yes
1987	354	97%	Yes
1988	347	95%	Yes
1989	363	99%	Yes
1990	357	98%	Yes
1991	347	95%	Yes
1992	325	89%	No
1993	360	99%	Yes
1994	362	99%	Yes
1995	358	98%	Yes
1996	366	100%	Yes
1997	331	91%	Yes
1998	361	99%	Yes
1999	364	100%	Yes
2000	366	100%	Yes
2001	365	100%	Yes
2002	365	100%	Yes
2003	365	100%	Yes
2004	366	100%	Yes
2005	365	100%	Yes
2006	365	100%	Yes
2007	365	100%	Yes
2008	360	98%	Yes
2009	365	100%	Yes
2010	365	100%	Yes
2011	365	100%	Yes
2012	365	100%	Yes
2013	365	100%	Yes
2014	365	100%	Yes
2015	364	100%	Yes
2016	366	100%	Yes
2017	365	100%	Yes
2018	365	100%	Yes
2019	365	100%	Yes
2020	365	100%	Yes
2021	362	99%	Yes
2022	364	100%	Yes
2023	354	97%	Yes
2024	366	100%	Yes
2025	307	84%	No
2026	250	68%	No

Latest Records

Latest records at Iliamna AP
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
16 August 2026	Iliamna AP, US	daily rain	33.0 mm (1.3 in)	4.8 mm (0.19 in)	59 years	32 of 100 (Routine)
3 August 2026	Iliamna AP, US	daily rain	40.6 mm (1.6 in)	10.6 mm (0.4 in)	12 years	24 of 100 (Routine)
22 July 2026	Iliamna AP, US	daily rain	37.3 mm (1.5 in)	20.5 mm (0.8 in)	59 years	59 of 100 (Notable)
16 July 2026	Iliamna AP, US	daily low max (Tie)	9.4 C (48.9 F)	tie	67 years	7 of 100 (Routine)
14 July 2026	Iliamna AP, US	daily rain	30.2 mm (1.2 in)	14.2 mm (0.6 in)	47 years	46 of 100 (Notable)
4 July 2026	Iliamna AP, US	daily low max (Tie)	9.4 C (48.9 F)	tie	3 years	2 of 100 (Routine)
4 June 2026	Iliamna AP, US	daily high max	27.8 C (82.0 F)	2.8 C (5.0 F)	4 years	18 of 100 (Routine)
23 March 2026	Iliamna AP, US	daily low min	-26.1 C (-15.0 F)	1.7 C (3.1 F)	83 years	36 of 100 (Notable)
22 March 2026	Iliamna AP, US	daily low min	-27.2 C (-17.0 F)	1.6 C (2.9 F)	13 years	15 of 100 (Routine)
4 March 2026	Iliamna AP, US	daily low min (Tie)	-31.1 C (-24.0 F)	tie	69 years	7 of 100 (Routine)
3 March 2026	Iliamna AP, US	daily low min (Tie)	-27.8 C (-18.0 F)	tie	69 years	7 of 100 (Routine)
25 February 2026	Iliamna AP, US	daily low min (Tie)	-26.7 C (-16.1 F)	tie	72 years	7 of 100 (Routine)
10 February 2026	Iliamna AP, US	daily rain	8.6 mm (0.34 in)	0.5 mm (0.02 in)	60 years	20 of 100 (Routine)
11 January 2026	Iliamna AP, US	daily low min	-31.7 C (-25.1 F)	1.1 C (2.0 F)	18 years	16 of 100 (Routine)
10 January 2026	Iliamna AP, US	daily low min (Tie)	-30.0 C (-22.0 F)	tie	70 years	7 of 100 (Routine)
8 January 2026	Iliamna AP, US	daily low min	-32.2 C (-26.0 F)	0.5 C (0.9 F)	28 years	18 of 100 (Routine)
26 November 2025	Iliamna AP, US	daily high min (Tie)	2.8 C (37.0 F)	tie	78 years	8 of 100 (Routine)
25 August 2025	Iliamna AP, US	daily high min	13.3 C (55.9 F)	0.5 C (0.9 F)	35 years	22 of 100 (Routine)
14 May 2025	Iliamna AP, US	daily high min (Tie)	5.6 C (42.1 F)	tie	44 years	5 of 100 (Routine)
25 April 2025	Iliamna AP, US	daily high min (Tie)	3.9 C (39.0 F)	tie	28 years	4 of 100 (Routine)

Climate Trend

72 complete years, 1943 to 2024

One stripe for each of 72 complete years at Iliamna AP, 1943 to 2024. Blue stripes are years cooler than the station's own mean of 1.8 C (35.2 F); red stripes are warmer. The coolest year was 1956, at -2.1 C (28.2 F), and the warmest was 2019, at 5.6 C (42.1 F). The strongest colour marks a difference of 3.9 C (7.0 F).

Annual mean temperature at Iliamna AP as warming stripes, 1943 to 2024
Year	Annual mean temperature	Difference from the station mean
1943	1.5 C	-0.30 C
1944	2.4 C	+0.67 C
1945	1.3 C	-0.47 C
1946	-0.2 C	-1.97 C
1947	0.7 C	-1.06 C
1948	0.0 C	-1.77 C
1949	0.5 C	-1.22 C
1950	0.3 C	-1.48 C
1951	0.2 C	-1.58 C
1952	0.3 C	-1.51 C
1953	1.4 C	-0.33 C
1954	-0.5 C	-2.22 C
1955	-0.5 C	-2.26 C
1956	-2.1 C	-3.89 C
1957	2.7 C	+0.96 C
1958	2.0 C	+0.24 C
1959	0.7 C	-1.06 C
1960	2.1 C	+0.33 C
1961	-0.3 C	-2.09 C
1962	1.2 C	-0.54 C
1963	1.3 C	-0.49 C
1964	-0.2 C	-2.00 C
1965	0.8 C	-0.98 C
1966	0.1 C	-1.71 C
1967	1.5 C	-0.28 C
1968	0.9 C	-0.84 C
1969	1.6 C	-0.21 C
1977	2.3 C	+0.58 C
1978	4.1 C	+2.30 C
1979	2.7 C	+0.92 C
1980	1.5 C	-0.22 C
1981	3.5 C	+1.75 C
1982	1.0 C	-0.72 C
1983	3.1 C	+1.37 C
1984	2.1 C	+0.30 C
1985	1.5 C	-0.29 C
1986	2.2 C	+0.42 C
1987	2.4 C	+0.62 C
1988	2.6 C	+0.80 C
1989	1.5 C	-0.23 C
1990	1.2 C	-0.54 C
1991	2.0 C	+0.25 C
1993	3.8 C	+2.08 C
1994	1.5 C	-0.23 C
1995	2.6 C	+0.87 C
1996	1.2 C	-0.58 C
1998	2.0 C	+0.23 C
1999	-1.0 C	-2.79 C
2000	3.3 C	+1.52 C
2001	2.4 C	+0.66 C
2002	3.7 C	+1.98 C
2003	4.0 C	+2.20 C
2004	3.5 C	+1.69 C
2005	3.2 C	+1.48 C
2006	0.7 C	-1.05 C
2007	1.9 C	+0.09 C
2008	0.1 C	-1.64 C
2009	1.3 C	-0.51 C
2010	1.2 C	-0.58 C
2011	1.3 C	-0.44 C
2012	-0.2 C	-1.92 C
2013	3.2 C	+1.46 C
2014	4.8 C	+3.03 C
2015	4.3 C	+2.49 C
2016	5.4 C	+3.67 C
2017	2.3 C	+0.50 C
2018	3.8 C	+2.06 C
2019	5.6 C	+3.87 C
2020	1.9 C	+0.11 C
2021	1.0 C	-0.72 C
2022	3.0 C	+1.21 C
2024	1.6 C	-0.17 C

The annual mean temperature here has risen by 0.3 C (0.2 to 0.4) per decade over 1943 to 2024. In Fahrenheit: 0.6 F (0.3 to 0.8) per decade. The slope is a straight line fitted to 72 complete years; the brackets give its 95 percent interval.

Fitted temperature trends per decade at Iliamna AP
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.3 C (0.2 to 0.4) per decade	0.6 F (0.3 to 0.8) per decade	1943 to 2024	72	Rise
Mean daily maximum	0.3 C (0.1 to 0.4) per decade	0.5 F (0.3 to 0.7) per decade	1943 to 2024	72	Rise
Mean daily minimum	0.4 C (0.2 to 0.5) per decade	0.6 F (0.4 to 0.9) per decade	1943 to 2024	72	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

1920 to 2026

Yearly extremes at Iliamna AP: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	32.8 C (91.0 F)	1953	25.3 C (77.5 F)	90
Coldest night (TNn)	-43.9 C (-47.0 F)	1947	-31.1 C (-24.0 F)	90
Wettest day (Rx1day)	88.9 mm (3.5 in)	1985	38.9 mm (1.5 in)	90
Wettest five days (Rx5day)	134.7 mm (5.3 in)	2015	70.3 mm (2.8 in)	90
Longest dry spell (CDD)	109 days	2007	27 days	90

Hottest day (TXx)

The hottest day of the year at Iliamna AP, 1920 to 2026. The record is 32.8 C (91.0 F) in 1953, marked on the chart; the median year is 25.3 C (77.5 F).

Hottest day (TXx) at Iliamna AP by year
Year	Hottest day (TXx)
1920	15.0 C (59.0 F)
1921	18.9 C (66.0 F)
1922	23.9 C (75.0 F)
1923	5.6 C (42.1 F)
1939	5.0 C (41.0 F)
1941	21.7 C (71.1 F)
1942	22.2 C (72.0 F)
1943	26.1 C (79.0 F)
1944	26.1 C (79.0 F)
1945	23.3 C (73.9 F)
1946	21.7 C (71.1 F)
1947	26.7 C (80.1 F)
1948	21.1 C (70.0 F)
1949	26.7 C (80.1 F)
1950	25.6 C (78.1 F)
1951	27.8 C (82.0 F)
1952	25.0 C (77.0 F)
1953	32.8 C (91.0 F)
1954	23.3 C (73.9 F)
1955	27.2 C (81.0 F)
1956	23.9 C (75.0 F)
1957	26.7 C (80.1 F)
1958	20.6 C (69.1 F)
1959	23.3 C (73.9 F)
1960	25.6 C (78.1 F)
1961	22.2 C (72.0 F)
1962	26.7 C (80.1 F)
1963	27.8 C (82.0 F)
1964	23.9 C (75.0 F)
1965	24.4 C (75.9 F)
1966	25.0 C (77.0 F)
1967	27.8 C (82.0 F)
1968	28.3 C (82.9 F)
1969	27.8 C (82.0 F)
1970	23.3 C (73.9 F)
1971	25.6 C (78.1 F)
1972	5.0 C (41.0 F)
1973	21.7 C (71.1 F)
1975	26.7 C (80.1 F)
1976	25.6 C (78.1 F)
1977	25.6 C (78.1 F)
1978	26.7 C (80.1 F)
1979	26.1 C (79.0 F)
1980	25.6 C (78.1 F)
1981	25.6 C (78.1 F)
1982	23.9 C (75.0 F)
1983	25.6 C (78.1 F)
1984	24.4 C (75.9 F)
1985	23.9 C (75.0 F)
1986	24.4 C (75.9 F)
1987	28.3 C (82.9 F)
1988	23.3 C (73.9 F)
1989	23.3 C (73.9 F)
1990	25.0 C (77.0 F)
1991	23.3 C (73.9 F)
1992	22.2 C (72.0 F)
1993	28.3 C (82.9 F)
1994	23.3 C (73.9 F)
1995	25.0 C (77.0 F)
1996	25.6 C (78.1 F)
1997	27.8 C (82.0 F)
1998	22.8 C (73.0 F)
1999	24.4 C (75.9 F)
2000	26.1 C (79.0 F)
2001	24.4 C (75.9 F)
2002	28.9 C (84.0 F)
2003	28.9 C (84.0 F)
2004	28.3 C (82.9 F)
2005	25.0 C (77.0 F)
2006	26.7 C (80.1 F)
2007	27.2 C (81.0 F)
2008	23.3 C (73.9 F)
2009	25.6 C (78.1 F)
2010	22.8 C (73.0 F)
2011	22.8 C (73.0 F)
2012	24.4 C (75.9 F)
2013	29.4 C (84.9 F)
2014	26.7 C (80.1 F)
2015	30.0 C (86.0 F)
2016	26.1 C (79.0 F)
2017	26.7 C (80.1 F)
2018	27.2 C (81.0 F)
2019	30.0 C (86.0 F)
2020	26.7 C (80.1 F)
2021	23.3 C (73.9 F)
2022	26.7 C (80.1 F)
2023	25.0 C (77.0 F)
2024	25.0 C (77.0 F)
2025	24.4 C (75.9 F)
2026	27.8 C (82.0 F)

Coldest night (TNn)

The coldest night of the year at Iliamna AP, 1920 to 2026. The record is -43.9 C (-47.0 F) in 1947, marked on the chart; the median year is -31.1 C (-24.0 F).

Coldest night (TNn) at Iliamna AP by year
Year	Coldest night (TNn)
1920	-34.4 C (-29.9 F)
1921	-40.0 C (-40.0 F)
1922	-34.4 C (-29.9 F)
1923	-32.2 C (-26.0 F)
1939	-18.9 C (-2.0 F)
1941	-23.9 C (-11.0 F)
1942	-33.9 C (-29.0 F)
1943	-32.8 C (-27.0 F)
1944	-31.7 C (-25.1 F)
1945	-27.2 C (-17.0 F)
1946	-35.0 C (-31.0 F)
1947	-43.9 C (-47.0 F)
1948	-32.2 C (-26.0 F)
1949	-33.3 C (-27.9 F)
1950	-30.0 C (-22.0 F)
1951	-33.9 C (-29.0 F)
1952	-33.3 C (-27.9 F)
1953	-35.0 C (-31.0 F)
1954	-34.4 C (-29.9 F)
1955	-34.4 C (-29.9 F)
1956	-34.4 C (-29.9 F)
1957	-33.3 C (-27.9 F)
1958	-26.1 C (-15.0 F)
1959	-28.9 C (-20.0 F)
1960	-28.9 C (-20.0 F)
1961	-35.0 C (-31.0 F)
1962	-31.7 C (-25.1 F)
1963	-30.0 C (-22.0 F)
1964	-33.3 C (-27.9 F)
1965	-32.2 C (-26.0 F)
1966	-34.4 C (-29.9 F)
1967	-30.6 C (-23.1 F)
1968	-36.1 C (-33.0 F)
1969	-35.6 C (-32.1 F)
1970	-31.7 C (-25.1 F)
1971	-34.4 C (-29.9 F)
1972	-28.9 C (-20.0 F)
1973	-21.7 C (-7.1 F)
1975	-35.0 C (-31.0 F)
1976	-32.8 C (-27.0 F)
1977	-30.0 C (-22.0 F)
1978	-29.4 C (-20.9 F)
1979	-30.0 C (-22.0 F)
1980	-35.0 C (-31.0 F)
1981	-25.0 C (-13.0 F)
1982	-31.1 C (-24.0 F)
1983	-28.9 C (-20.0 F)
1984	-31.1 C (-24.0 F)
1985	-28.9 C (-20.0 F)
1986	-27.8 C (-18.0 F)
1987	-26.7 C (-16.1 F)
1988	-25.0 C (-13.0 F)
1989	-40.6 C (-41.1 F)
1990	-31.7 C (-25.1 F)
1991	-32.2 C (-26.0 F)
1992	-27.2 C (-17.0 F)
1993	-33.9 C (-29.0 F)
1994	-29.4 C (-20.9 F)
1995	-29.4 C (-20.9 F)
1996	-27.8 C (-18.0 F)
1997	-33.3 C (-27.9 F)
1998	-30.0 C (-22.0 F)
1999	-36.7 C (-34.1 F)
2000	-31.1 C (-24.0 F)
2001	-31.7 C (-25.1 F)
2002	-27.2 C (-17.0 F)
2003	-23.9 C (-11.0 F)
2004	-29.4 C (-20.9 F)
2005	-25.0 C (-13.0 F)
2006	-33.3 C (-27.9 F)
2007	-30.6 C (-23.1 F)
2008	-35.0 C (-31.0 F)
2009	-35.0 C (-31.0 F)
2010	-28.3 C (-18.9 F)
2011	-29.4 C (-20.9 F)
2012	-30.0 C (-22.0 F)
2013	-25.0 C (-13.0 F)
2014	-24.9 C (-12.8 F)
2015	-24.9 C (-12.8 F)
2016	-22.7 C (-8.9 F)
2017	-29.9 C (-21.8 F)
2018	-26.6 C (-15.9 F)
2019	-28.2 C (-18.8 F)
2020	-29.9 C (-21.8 F)
2021	-27.7 C (-17.9 F)
2022	-34.3 C (-29.7 F)
2023	-26.6 C (-15.9 F)
2024	-34.3 C (-29.7 F)
2025	-25.6 C (-14.1 F)
2026	-32.2 C (-26.0 F)

Wettest day (Rx1day)

The wettest day of the year at Iliamna AP, 1920 to 2026. The record is 88.9 mm (3.5 in) in 1985, marked on the chart; the median year is 38.9 mm (1.5 in).

Wettest day (Rx1day) at Iliamna AP by year
Year	Wettest day (Rx1day)
1920	61.0 mm (2.4 in)
1921	45.7 mm (1.8 in)
1922	50.8 mm (2.0 in)
1923	45.7 mm (1.8 in)
1939	3.8 mm (0.15 in)
1941	27.2 mm (1.1 in)
1942	29.5 mm (1.2 in)
1943	58.4 mm (2.3 in)
1944	42.4 mm (1.7 in)
1945	35.1 mm (1.4 in)
1946	43.7 mm (1.7 in)
1947	31.8 mm (1.3 in)
1948	28.7 mm (1.1 in)
1949	54.1 mm (2.1 in)
1950	45.7 mm (1.8 in)
1951	31.8 mm (1.3 in)
1952	36.3 mm (1.4 in)
1953	33.5 mm (1.3 in)
1954	42.4 mm (1.7 in)
1955	33.3 mm (1.3 in)
1956	39.1 mm (1.5 in)
1957	55.4 mm (2.2 in)
1958	62.0 mm (2.4 in)
1959	48.5 mm (1.9 in)
1960	39.9 mm (1.6 in)
1961	38.6 mm (1.5 in)
1962	26.7 mm (1.1 in)
1963	48.3 mm (1.9 in)
1964	28.7 mm (1.1 in)
1965	57.9 mm (2.3 in)
1966	36.1 mm (1.4 in)
1967	45.2 mm (1.8 in)
1968	42.9 mm (1.7 in)
1969	38.1 mm (1.5 in)
1970	24.6 mm (1.0 in)
1971	27.9 mm (1.1 in)
1972	20.8 mm (0.8 in)
1973	56.6 mm (2.2 in)
1975	57.7 mm (2.3 in)
1976	26.9 mm (1.1 in)
1977	44.5 mm (1.8 in)
1978	40.6 mm (1.6 in)
1979	38.1 mm (1.5 in)
1980	49.8 mm (2.0 in)
1981	26.9 mm (1.1 in)
1982	42.4 mm (1.7 in)
1983	51.8 mm (2.0 in)
1984	67.8 mm (2.7 in)
1985	88.9 mm (3.5 in)
1986	54.9 mm (2.2 in)
1987	56.4 mm (2.2 in)
1988	28.7 mm (1.1 in)
1989	53.8 mm (2.1 in)
1990	35.1 mm (1.4 in)
1991	21.3 mm (0.8 in)
1992	30.5 mm (1.2 in)
1993	28.4 mm (1.1 in)
1994	36.3 mm (1.4 in)
1995	36.6 mm (1.4 in)
1996	44.5 mm (1.8 in)
1997	25.9 mm (1.0 in)
1998	52.8 mm (2.1 in)
1999	34.8 mm (1.4 in)
2000	32.8 mm (1.3 in)
2001	31.5 mm (1.2 in)
2002	39.4 mm (1.6 in)
2003	58.9 mm (2.3 in)
2004	60.7 mm (2.4 in)
2005	57.4 mm (2.3 in)
2006	43.7 mm (1.7 in)
2007	39.1 mm (1.5 in)
2008	30.5 mm (1.2 in)
2009	31.0 mm (1.2 in)
2010	31.0 mm (1.2 in)
2011	40.1 mm (1.6 in)
2012	37.6 mm (1.5 in)
2013	30.0 mm (1.2 in)
2014	52.8 mm (2.1 in)
2015	75.2 mm (3.0 in)
2016	31.8 mm (1.3 in)
2017	23.9 mm (0.9 in)
2018	28.2 mm (1.1 in)
2019	55.1 mm (2.2 in)
2020	21.3 mm (0.8 in)
2021	27.4 mm (1.1 in)
2022	46.7 mm (1.8 in)
2023	36.8 mm (1.4 in)
2024	36.8 mm (1.4 in)
2025	21.6 mm (0.9 in)
2026	40.6 mm (1.6 in)

Wettest five days (Rx5day)

The wettest five days of the year at Iliamna AP, 1920 to 2026. The record is 134.7 mm (5.3 in) in 2015, marked on the chart; the median year is 70.3 mm (2.8 in).

Wettest five days (Rx5day) at Iliamna AP by year
Year	Wettest five days (Rx5day)
1920	78.8 mm (3.1 in)
1921	102.5 mm (4.0 in)
1922	88.4 mm (3.5 in)
1923	54.4 mm (2.1 in)
1939	6.6 mm (0.26 in)
1941	44.0 mm (1.7 in)
1942	45.7 mm (1.8 in)
1943	97.6 mm (3.8 in)
1944	86.0 mm (3.4 in)
1945	71.6 mm (2.8 in)
1946	84.8 mm (3.3 in)
1947	71.2 mm (2.8 in)
1948	55.5 mm (2.2 in)
1949	103.2 mm (4.1 in)
1950	127.8 mm (5.0 in)
1951	55.8 mm (2.2 in)
1952	59.6 mm (2.3 in)
1953	66.5 mm (2.6 in)
1954	78.7 mm (3.1 in)
1955	66.1 mm (2.6 in)
1956	44.7 mm (1.8 in)
1957	57.0 mm (2.2 in)
1958	66.8 mm (2.6 in)
1959	125.7 mm (4.9 in)
1960	71.5 mm (2.8 in)
1961	98.7 mm (3.9 in)
1962	41.6 mm (1.6 in)
1963	113.9 mm (4.5 in)
1964	62.0 mm (2.4 in)
1965	70.3 mm (2.8 in)
1966	89.3 mm (3.5 in)
1967	126.8 mm (5.0 in)
1968	69.8 mm (2.7 in)
1969	71.9 mm (2.8 in)
1970	41.0 mm (1.6 in)
1971	86.4 mm (3.4 in)
1972	52.1 mm (2.1 in)
1973	61.0 mm (2.4 in)
1975	106.8 mm (4.2 in)
1976	45.0 mm (1.8 in)
1977	54.8 mm (2.2 in)
1978	54.7 mm (2.2 in)
1979	88.4 mm (3.5 in)
1980	94.5 mm (3.7 in)
1981	49.5 mm (1.9 in)
1982	72.3 mm (2.8 in)
1983	110.7 mm (4.4 in)
1984	101.5 mm (4.0 in)
1985	126.7 mm (5.0 in)
1986	70.2 mm (2.8 in)
1987	84.5 mm (3.3 in)
1988	59.1 mm (2.3 in)
1989	70.6 mm (2.8 in)
1990	59.9 mm (2.4 in)
1991	45.7 mm (1.8 in)
1992	42.4 mm (1.7 in)
1993	57.1 mm (2.2 in)
1994	46.0 mm (1.8 in)
1995	80.3 mm (3.2 in)
1996	93.8 mm (3.7 in)
1997	48.0 mm (1.9 in)
1998	99.0 mm (3.9 in)
1999	64.7 mm (2.5 in)
2000	72.7 mm (2.9 in)
2001	53.1 mm (2.1 in)
2002	69.1 mm (2.7 in)
2003	121.4 mm (4.8 in)
2004	106.2 mm (4.2 in)
2005	97.7 mm (3.8 in)
2006	71.7 mm (2.8 in)
2007	68.3 mm (2.7 in)
2008	67.1 mm (2.6 in)
2009	52.2 mm (2.1 in)
2010	46.3 mm (1.8 in)
2011	70.6 mm (2.8 in)
2012	91.1 mm (3.6 in)
2013	66.6 mm (2.6 in)
2014	99.6 mm (3.9 in)
2015	134.7 mm (5.3 in)
2016	73.7 mm (2.9 in)
2017	50.1 mm (2.0 in)
2018	52.0 mm (2.0 in)
2019	89.2 mm (3.5 in)
2020	58.9 mm (2.3 in)
2021	67.0 mm (2.6 in)
2022	64.2 mm (2.5 in)
2023	91.2 mm (3.6 in)
2024	70.3 mm (2.8 in)
2025	49.4 mm (1.9 in)
2026	59.3 mm (2.3 in)

Longest dry spell (CDD)

The longest dry spell of the year at Iliamna AP, 1920 to 2026. The record is 109 days in 2007, marked on the chart; the median year is 27 days.

Longest dry spell (CDD) at Iliamna AP by year
Year	Longest dry spell (CDD)
1920	33 days
1921	20 days
1922	20 days
1923	17 days
1939	11 days
1941	19 days
1942	22 days
1943	39 days
1944	36 days
1945	30 days
1946	19 days
1947	24 days
1948	37 days
1949	22 days
1950	75 days
1951	31 days
1952	13 days
1953	22 days
1954	34 days
1955	23 days
1956	27 days
1957	28 days
1958	17 days
1959	44 days
1960	42 days
1961	20 days
1962	19 days
1963	30 days
1964	15 days
1965	29 days
1966	19 days
1967	34 days
1968	33 days
1969	28 days
1970	21 days
1971	10 days
1972	16 days
1973	13 days
1975	30 days
1976	19 days
1977	31 days
1978	16 days
1979	30 days
1980	34 days
1981	23 days
1982	31 days
1983	33 days
1984	32 days
1985	32 days
1986	61 days
1987	26 days
1988	21 days
1989	23 days
1990	25 days
1991	21 days
1992	41 days
1993	26 days
1994	31 days
1995	38 days
1996	32 days
1997	27 days
1998	28 days
1999	23 days
2000	15 days
2001	23 days
2002	48 days
2003	37 days
2004	19 days
2005	21 days
2006	51 days
2007	109 days
2008	26 days
2009	23 days
2010	30 days
2011	22 days
2012	27 days
2013	31 days
2014	44 days
2015	41 days
2016	31 days
2017	40 days
2018	19 days
2019	43 days
2020	18 days
2021	31 days
2022	43 days
2023	16 days
2024	26 days
2025	23 days
2026	26 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

72 years with a frost

Across 72 years with a frost, the median last spring frost at Iliamna AP falls on 17 May and the median first autumn frost on 25 September, which leaves a median of 131 days between them.

In 1993 to 2024 the median growing season was 139 days. That is 11 days more than in 1943 to 1979.

Fitted over all years, the growing season changes by +3.2 days per decade at this station.

Frost dates and growing season at Iliamna AP
Measure	Median, all years	Earliest period (1943 to 1979)	Recent period (1993 to 2024)	Recent against earliest	Fitted trend
Last spring frost	17 May	21 May	14 May	7 days earlier	-1.7 days per decade
First autumn frost	25 September	24 September	28 September	4 days later	+1.4 days per decade
Growing days	131 days	128 days	139 days	11 days more	+3.2 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

75 years, 1921 to 2024

A day with at least 39.2 mm (1.5 in) of rain is expected about once in 2 years. A day with at least 82.7 mm (3.3 in) of rain is expected about once in 100 years.

Rainfall return levels at Iliamna 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	39.2 mm (1.5 in)
5 years	50.6 mm (2.0 in)
10 years	58.3 mm (2.3 in)
25 years	68.0 mm (2.7 in)
50 years	75.3 mm (3.0 in)
100 years	82.7 mm (3.3 in)	Longer than the 75 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, 75 years of values from 1921 to 2024.

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: 88.9 mm (3.5 in) in 1985; 75.2 mm (3.0 in) in 2015; 67.8 mm (2.7 in) in 1984.

Station Changes

1 suspected

One change was suspected in the annual mean temperature of Iliamna AP, at 2015. Each is measured against neighbouring stations.

Relative to 5 neighbouring stations, the station's annual mean temperature from 2015 ran 0.5 C (0.9 F) lower than in the years before (possible change).

Suspected changes in the annual mean temperature at Iliamna AP, against neighbouring stations
Year	Shift (C)	Shift (F)	Strength	Neighbours
2015	-0.5	-0.9	possible	5

Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.

Climate Twins

2009 to 2024 against 1961 to 1990

Over 2009 to 2024, Iliamna AP had a mean temperature of 2.7 C (36.9 F) and 679.8 mm (26.8 in) of rain a year. The 3 stations whose 1961 to 1990 climate was closest to that are McCulloch (Canada, 2,503 km away), Ruxton Park (United States, 4,160 km away) and Cooper Lake Project (United States, 299 km away).

Climate twins of Iliamna AP: stations whose 1961 to 1990 climate is closest to its 2009 to 2024 climate
Twin station	Country	Distance away	Mean temperature, 1961-1990	Rain a year, 1961-1990	Climate difference
McCulloch	Canada	2,503 km (1,555 mi)	2.7 C (36.9 F)	676.9 mm (26.6 in)	0.99
Ruxton Park	United States	4,160 km (2,585 mi)	2.5 C (36.4 F)	600.6 mm (23.6 in)	1.06
Cooper Lake Project	United States	299 km (186 mi)	2.9 C (37.2 F)	771.6 mm (30.4 in)	1.08

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 Iliamna AP standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Iliamna 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.

Data as of 2026-10-15. Last revised 15 October 2026 (2026-10-15).