Climate averages 1991–2020

Anchorage weather
by month.

See how the year changes. July has the highest average daily maximum; April has the lowest average monthly rainfall.

Long-term climate patterns, not a forecast for a particular trip.

Warmest month 17.3°C July, average high

Coolest month -10.9°C January, average low

Wettest month 117 mm September, monthly total

Driest month 29 mm April, monthly total

Across the year Anchorage averages a daytime high of 5.0°C and a nighttime low of -0.3°C, with about 763 mm of precipitation on roughly 132 days. July is the warmest month (average high 17.3°C) and January the coolest (-6.8°C). September is the wettest month with 117 mm; April is the driest with 29 mm.

The annual picture

A year in Anchorage

30-year average

Average highAverage low°C

Monthly precipitation

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Anchorage climate table

1991–2020

Monthly climate averages for Anchorage, 1991–2020
Month	Average highHigh / low	Average low	Precipitation mm/month	Wet days ≥1 mm/day	Daylight hours/dayDaylight h/day
January	-6.8°C-10.9°C	-10.9°C	50	10.4	6.56 h
February	-3.9°C-8.5°C	-8.5°C	50	9.7	8.99 h
March	-1.2°C-7.2°C	-7.2°C	38	8.5	11.712 h
April	4.7°C-1.8°C	-1.8°C	29	7.3	14.715 h
May	10.1°C2.9°C	2.9°C	30	7.1	17.417 h
June	15.4°C9.0°C	9.0°C	40	8.9	19.219 h
July	17.3°C11.9°C	11.9°C	73	12.5	18.418 h
August	16.3°C11.0°C	11.0°C	107	14.8	15.916 h
September	11.8°C6.7°C	6.7°C	117	15.3	13.013 h
October	4.4°C-0.2°C	-0.2°C	90	13.2	10.110 h
November	-2.6°C-6.8°C	-6.8°C	66	11.7	7.47 h
December	-5.1°C-9.4°C	-9.4°C	73	12.9	5.66 h

Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

What do the high and low temperatures mean?

We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.

How is a rain day counted?

A local calendar day (standard time, UTC-9, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.

Where do the numbers come from?

ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 61.20°, -149.90° (2 km from the city centre), adjusted up by 0.5°C for the difference between the city's elevation (16 m) and the cell's (93 m). Rain comes from the 0.25° cell at 61.25°, -150.00°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.

Does this page show sunshine, humidity or sea temperature?

No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.