September is one of the warmer months of the year in Anchorage, with average highs near 10.6°C and lows around 3.6°C (mean 7.1°C). It is a relatively wet time of year, averaging 210 mm of rainfall and 83% relative humidity across the period.
September is one of the warmer months of the year in Anchorage. Across 45 years of records, the warmest September in Anchorage was 2018 — when the month averaged 10.1°C — while the coldest was 1992 at 1.4°C. Typical September days reach 10.6°C with nights near 3.6°C. The long-term trend is warming, about 0.4°C per decade.
September is a relatively wet time of year in Anchorage, averaging 210 mm of rainfall. The wettest September on record was 2012 with 442 mm, while the driest was 2010 at 69 mm.
Relative humidity in Anchorage during September averages 83%. The most humid September was 1989 at 89%, and the least humid was 2003 at 76%.
September receives about 2.4 kWh/m²/day of solar energy in Anchorage. The sunniest September was 2018 at 3.1 kWh/m²/day, and the cloudiest were 1990 and 2012 at 1.8.
Average wind speed in Anchorage during September is 1.8 m/s. The windiest September was 2013 at 2.7 m/s, while the calmest was 1995 at 1.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 6.6°C | 6.7°C | 7.3°C | 7.7°C | 7.4°C | +0.8°C |
| Avg High | 10.3°C | 10.1°C | 11.0°C | 11.2°C | 10.7°C | +0.4°C |
| Avg Low | 2.9°C | 3.2°C | 3.7°C | 4.2°C | 4.1°C | +1.2°C |
| Avg Rain | 182 mm | 240 mm | 197 mm | 228 mm | 196 mm | +14 mm |
September temperatures in Anchorage have risen by about 0.8°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -11.9°C (2004) to a record high of 20.4°C (2016).
Rainfall in September is a relatively wet time of year, averaging 210 mm, with a wettest year of 442 mm.
A good time to visit Anchorage
September is a good time to visit Anchorage, with days averaging 10.6°C and nights around 3.6°C (mean 7.1°C, warmer than Anchorage's yearly average) and higher rainfall. July and June are marginally more temperate, but September still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 11.2°C | 7.9°C | 4.5°C | 16.4°C | -1.8°C | 212 mm | 86% | 2.1 m/s | 2 |
| 2024 | 10.7°C | 7.6°C | 4.5°C | 15.2°C | -0.7°C | 183 mm | 86% | 1.8 m/s | 2 |
| 2023 | 9.9°C | 6.5°C | 3.2°C | 17.0°C | -2.0°C | 163 mm | 82% | 1.7 m/s | 2.4 |
| 2022 | 11.2°C | 8.1°C | 5.1°C | 15.3°C | 1.2°C | 273 mm | 88% | 1.7 m/s | 2 |
| 2021 | 9.2°C | 6.0°C | 2.7°C | 15.4°C | -4.0°C | 139 mm | 80% | 2.2 m/s | 2.4 |
| 2020 | 12.0°C | 8.4°C | 4.8°C | 16.5°C | 0.9°C | 205 mm | 84% | 1.8 m/s | 2.4 |
| 2019 | 12.0°C | 8.4°C | 4.9°C | 18.7°C | -1.7°C | 221 mm | 83% | 1.7 m/s | 2 |
| 2018 🔥 | 14.3°C | 10.1°C | 5.8°C | 18.3°C | 2.2°C | 70 mm | 78% | 1.9 m/s | 3.1 |
| 2017 | 10.9°C | 7.9°C | 4.9°C | 16.0°C | -1.1°C | 318 mm | 88% | 1.8 m/s | 2 |
| 2016 | 12.2°C | 8.5°C | 4.8°C | 20.4°C | -1.7°C | 219 mm | 82% | 1.6 m/s | 2.4 |
| 2015 | 8.9°C | 5.6°C | 2.2°C | 15.4°C | -4.7°C | 246 mm | 83% | 1.9 m/s | 2.2 |
| 2014 | 11.2°C | 7.5°C | 3.8°C | 17.6°C | -2.0°C | 254 mm | 83% | 1.9 m/s | 2.4 |
| 2013 | 9.1°C | 6.2°C | 3.3°C | 15.5°C | -3.3°C | 249 mm | 82% | 2.7 m/s | 2.1 |
| 2012 🌧️ | 9.5°C | 6.4°C | 3.4°C | 13.2°C | -3.2°C | 442 mm | 86% | 2.2 m/s | 1.8 |
| 2011 | 10.6°C | 7.3°C | 4.1°C | 15.9°C | -2.2°C | 193 mm | 86% | 1.4 m/s | 2.1 |
| 2010 | 13.2°C | 8.9°C | 4.7°C | 19.9°C | -3.5°C | 69 mm | 76% | 2 m/s | 2.8 |
| 2009 | 11.2°C | 7.7°C | 4.3°C | 19.5°C | -3.6°C | 137 mm | 82% | 1.3 m/s | 2.4 |
| 2008 | 9.9°C | 7.1°C | 4.3°C | 14.0°C | -1.9°C | 330 mm | 87% | 1.3 m/s | 1.9 |
| 2007 | 11.6°C | 8.1°C | 4.7°C | 16.1°C | -0.2°C | 199 mm | 85% | 1.6 m/s | 2.3 |
| 2006 | 11.8°C | 8.5°C | 5.2°C | 17.6°C | -2.3°C | 232 mm | 83% | 1.3 m/s | 2.4 |
| 2005 | 11.4°C | 8.1°C | 4.8°C | 16.6°C | 0.4°C | 326 mm | 86% | 1.7 m/s | 2.1 |
| 2004 | 8.3°C | 4.1°C | -0.2°C | 16.4°C | -11.9°C | 169 mm | 76% | 1.9 m/s | 2.7 |
| 2003 | 11.2°C | 6.9°C | 2.6°C | 18.4°C | -3.0°C | 94 mm | 76% | 2.2 m/s | 3 |
| 2002 | 11.2°C | 8.0°C | 4.8°C | 15.5°C | -1.5°C | 249 mm | 86% | 2.1 m/s | 2.2 |
| 2001 | 12.7°C | 8.7°C | 4.7°C | 16.8°C | 0.4°C | 122 mm | 82% | 1.5 m/s | 2.6 |
| 2000 | 10.2°C | 5.9°C | 1.7°C | 16.0°C | -3.9°C | 109 mm | 78% | 2.2 m/s | 2.7 |
| 1999 | 10.8°C | 7.6°C | 4.3°C | 15.5°C | -1.0°C | 257 mm | 83% | 1.8 m/s | 2.6 |
| 1998 | 10.8°C | 7.3°C | 3.8°C | 14.2°C | -1.9°C | 137 mm | 83% | 1.8 m/s | 2.6 |
| 1997 | 11.9°C | 8.5°C | 5.2°C | 17.3°C | -0.7°C | 272 mm | 84% | 1.6 m/s | 2.5 |
| 1996 | 8.3°C | 4.4°C | 0.4°C | 19.8°C | -8.2°C | 215 mm | 82% | 1.9 m/s | 2.5 |
| 1995 | 12.2°C | 9.5°C | 6.7°C | 14.9°C | 0.8°C | 359 mm | 89% | 1.2 m/s | 2.1 |
| 1994 | 10.6°C | 6.7°C | 2.8°C | 16.2°C | -2.7°C | 180 mm | 81% | 1.7 m/s | 2.6 |
| 1993 | 9.7°C | 6.4°C | 3.1°C | 15.2°C | -6.3°C | 297 mm | 85% | 2 m/s | 2.4 |
| 1992 ❄️ | 5.2°C | 1.4°C | -2.5°C | 14.1°C | -10.3°C | 104 mm | 77% | 2.5 m/s | 2.7 |
| 1991 | 10.8°C | 7.8°C | 4.7°C | 17.2°C | 0.1°C | 267 mm | 88% | 1.6 m/s | 2.3 |
| 1990 | 10.3°C | 6.9°C | 3.5°C | 18.7°C | -2.5°C | 315 mm | 86% | 1.8 m/s | 1.8 |
| 1989 | 11.2°C | 8.0°C | 4.9°C | 16.6°C | -0.4°C | 282 mm | 89% | 1.5 m/s | 2 |
| 1988 | 10.6°C | 6.7°C | 2.9°C | 14.8°C | -2.9°C | 132 mm | 82% | 1.8 m/s | 2.7 |
| 1987 | 9.1°C | 5.8°C | 2.4°C | 15.8°C | -3.9°C | 226 mm | 84% | 2.1 m/s | 2.3 |
| 1986 | 10.4°C | 6.5°C | 2.5°C | 17.2°C | -3.7°C | 167 mm | 81% | 1.7 m/s | 2.5 |
| 1985 | 10.6°C | 6.5°C | 2.4°C | 17.0°C | -2.7°C | 170 mm | 80% | 1.9 m/s | 2.5 |
| 1984 | 12.2°C | 7.9°C | 3.6°C | 17.2°C | -1.6°C | 161 mm | 80% | 1.5 m/s | 2.5 |
| 1983 | 8.8°C | 4.8°C | 0.8°C | 15.3°C | -8.8°C | 106 mm | 76% | 2 m/s | — |
| 1982 | 9.7°C | 6.6°C | 3.5°C | 14.0°C | -2.1°C | 273 mm | 85% | 1.7 m/s | — |
| 1981 | 9.7°C | 6.3°C | 2.8°C | 17.3°C | -3.3°C | 118 mm | 82% | 2.1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 10.6°C with lows near 3.6°C (mean 7.1°C), based on 45 years of NASA POWER data.
September averages 210 mm of rainfall in Anchorage, a relatively wet time of year. The wettest on record was 442 mm in 2012.
The hottest September reached 20.4°C in 2016. The coldest dipped to -11.9°C in 2004.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.8°C. Daytime highs moved from 10.2°C to 10.4°C and overnight lows from 2.6°C to 4°C over the same span.
September is one of the warmer months of the year in Anchorage and a relatively wet time of year, so plan for around 10.6°C daytime highs and 3.6°C at night.
Not quite — September is the 9th coolest month in Anchorage, averaging 7.1°C.
For September in Anchorage, pack warm layers and a jacket for chilly mornings, with typical highs of 10.6°C and lows of 3.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 83% — quite humid.
Average wind speed in September is 1.8 m/s. The windiest September on record averaged 2.7 m/s (2013).
The wettest September on record was 2012 with 442 mm. On average, September sees 210 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Anchorage behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
