September is one of the warmer months of the year in Fairbanks, with average highs near 9.3°C and lows around 1.6°C (mean 5.5°C). It is a relatively wet time of year, averaging 57 mm of rainfall and 85% relative humidity across the period.
September is one of the warmer months of the year in Fairbanks. Across 45 years of records, the warmest September in Fairbanks was 1995 — when the month averaged 9°C — while the coldest was 1992 at -2.7°C. Typical September days reach 9.3°C with nights near 1.6°C. The long-term trend is warming, about 0.4°C per decade.
September is a relatively wet time of year in Fairbanks, averaging 57 mm of rainfall. The wettest September on record was 1993 with 102 mm, while the driest was 1997 at 24 mm.
Relative humidity in Fairbanks during September averages 85%. The most humid September was 2025 at 91%, and the least humid was 2010 at 80%.
September receives about 2.3 kWh/m²/day of solar energy in Fairbanks. The sunniest September was 2010 at 2.8 kWh/m²/day, and the cloudiest were 2005 and 2025 at 1.8.
Average wind speed in Fairbanks during September is 1.4 m/s. The windiest Septembers were 1989, 1992 and 2012 at 1.6 m/s, while the calmest were 2001 and 2007 at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 5.0°C | 4.9°C | 5.5°C | 6.1°C | 5.7°C | +0.7°C |
| Avg High | 9.0°C | 8.9°C | 9.5°C | 10.1°C | 9.1°C | +0.1°C |
| Avg Low | 1.0°C | 1.0°C | 1.6°C | 2.2°C | 2.3°C | +1.3°C |
| Avg Rain | 48 mm | 57 mm | 57 mm | 63 mm | 62 mm | +14 mm |
September temperatures in Fairbanks have risen by about 0.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -18.9°C (1992) to a record high of 19.8°C (1989).
Rainfall in September is a relatively wet time of year, averaging 57 mm, with a wettest year of 102 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.3°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
A good time to visit Fairbanks
September is a good time to visit Fairbanks, with days averaging 9.3°C and nights around 1.6°C (mean 5.5°C, warmer than Fairbanks's yearly average) and moderate 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 | 9.3°C | 6.0°C | 2.7°C | 18.4°C | -6.9°C | 89 mm | 91% | 1.2 m/s | 1.8 |
| 2024 | 8.6°C | 5.5°C | 2.4°C | 16.1°C | -1.8°C | 53 mm | 91% | 1.2 m/s | 2 |
| 2023 | 8.4°C | 5.0°C | 1.6°C | 13.1°C | -3.2°C | 56 mm | 89% | 1.3 m/s | 1.9 |
| 2022 | 10.0°C | 6.5°C | 2.9°C | 13.9°C | -1.1°C | 71 mm | 89% | 1.3 m/s | 2 |
| 2021 | 8.3°C | 4.5°C | 0.7°C | 18.3°C | -8.3°C | 26 mm | 85% | 1.2 m/s | 2.3 |
| 2020 | 9.9°C | 6.5°C | 3.2°C | 15.1°C | -0.7°C | 77 mm | 89% | 1.4 m/s | 2 |
| 2019 | 11.4°C | 7.5°C | 3.6°C | 17.8°C | -2.2°C | 41 mm | 87% | 1.2 m/s | 2.3 |
| 2018 | 10.2°C | 6.7°C | 3.2°C | 14.3°C | -1.6°C | 85 mm | 89% | 1.3 m/s | 2.1 |
| 2017 | 10.8°C | 7.0°C | 3.2°C | 17.2°C | -2.5°C | 62 mm | 85% | 1.5 m/s | 2.2 |
| 2016 | 9.8°C | 5.9°C | 2.0°C | 17.9°C | -2.5°C | 80 mm | 86% | 1.4 m/s | 2.3 |
| 2015 | 7.1°C | 3.5°C | -0.1°C | 16.2°C | -6.1°C | 102 mm | 85% | 1.3 m/s | 2.2 |
| 2014 | 10.0°C | 5.7°C | 1.4°C | 19.8°C | -4.5°C | 44 mm | 82% | 1.5 m/s | 2.6 |
| 2013 | 8.6°C | 4.7°C | 0.9°C | 18.1°C | -5.5°C | 74 mm | 84% | 1.5 m/s | 2 |
| 2012 | 10.2°C | 6.2°C | 2.2°C | 17.0°C | -3.1°C | 48 mm | 81% | 1.6 m/s | 2 |
| 2011 | 11.6°C | 7.5°C | 3.5°C | 17.7°C | -2.1°C | 62 mm | 81% | 1.4 m/s | 2.2 |
| 2010 | 11.1°C | 6.5°C | 2.0°C | 16.6°C | -8.6°C | 30 mm | 80% | 1.4 m/s | 2.8 |
| 2009 | 10.7°C | 6.5°C | 2.4°C | 18.2°C | -6.8°C | 40 mm | 85% | 1.3 m/s | 2.3 |
| 2008 | 9.7°C | 5.9°C | 2.1°C | 16.6°C | -5.4°C | 42 mm | 87% | 1.3 m/s | 2.1 |
| 2007 | 10.7°C | 6.7°C | 2.8°C | 17.6°C | -4.3°C | 56 mm | 84% | 1.1 m/s | 2.3 |
| 2006 | 12.2°C | 7.9°C | 3.6°C | 17.3°C | -5.2°C | 52 mm | 87% | 1.3 m/s | 2.4 |
| 2005 | 9.0°C | 5.7°C | 2.5°C | 14.4°C | -5.2°C | 93 mm | 90% | 1.3 m/s | 1.8 |
| 2004 | 6.3°C | 2.3°C | -1.7°C | 14.1°C | -6.5°C | 76 mm | 83% | 1.3 m/s | 2.2 |
| 2003 | 6.9°C | 3.1°C | -0.8°C | 14.4°C | -6.1°C | 61 mm | 83% | 1.5 m/s | 2.4 |
| 2002 | 10.7°C | 6.6°C | 2.5°C | 18.2°C | -2.9°C | 50 mm | 87% | 1.2 m/s | 2.2 |
| 2001 | 12.0°C | 7.4°C | 2.8°C | 15.5°C | -1.2°C | 27 mm | 84% | 1.1 m/s | 2.7 |
| 2000 | 6.8°C | 3.3°C | -0.2°C | 12.0°C | -7.6°C | 74 mm | 87% | 1.3 m/s | 2.2 |
| 1999 | 9.6°C | 5.5°C | 1.5°C | 16.5°C | -9.3°C | 64 mm | 83% | 1.4 m/s | 2.4 |
| 1998 | 9.4°C | 5.8°C | 2.1°C | 14.7°C | -4.5°C | 41 mm | 86% | 1.5 m/s | 2.4 |
| 1997 | 12.1°C | 8.0°C | 3.8°C | 18.3°C | -2.0°C | 24 mm | 85% | 1.2 m/s | 2.5 |
| 1996 | 7.4°C | 3.6°C | -0.3°C | 15.9°C | -5.7°C | 74 mm | 84% | 1.3 m/s | 2.2 |
| 1995 🔥 | 13.0°C | 9.0°C | 5.1°C | 18.7°C | -1.5°C | 52 mm | 86% | 1.5 m/s | 2.4 |
| 1994 | 8.9°C | 4.7°C | 0.5°C | 16.2°C | -4.7°C | 29 mm | 84% | 1.3 m/s | 2.3 |
| 1993 🌧️ | 8.2°C | 4.8°C | 1.3°C | 17.5°C | -6.1°C | 102 mm | 85% | 1.5 m/s | 2.1 |
| 1992 ❄️ | 1.6°C | -2.7°C | -7.1°C | 14.2°C | -18.9°C | 41 mm | 86% | 1.6 m/s | 2.6 |
| 1991 | 10.4°C | 6.3°C | 2.2°C | 17.2°C | -1.8°C | 62 mm | 87% | 1.5 m/s | 2.3 |
| 1990 | 8.0°C | 4.3°C | 0.7°C | 13.0°C | -4.5°C | 77 mm | 87% | 1.5 m/s | 2.1 |
| 1989 | 11.0°C | 6.7°C | 2.4°C | 19.8°C | -3.0°C | 45 mm | 84% | 1.6 m/s | 2.5 |
| 1988 | 9.3°C | 5.2°C | 1.2°C | 13.5°C | -6.6°C | 28 mm | 83% | 1.2 m/s | 2.3 |
| 1987 | 8.5°C | 4.2°C | 0.0°C | 14.8°C | -3.9°C | 56 mm | 84% | 1.4 m/s | 2.4 |
| 1986 | 9.1°C | 5.4°C | 1.6°C | 17.6°C | -5.5°C | 59 mm | 86% | 1.3 m/s | 2.2 |
| 1985 | 6.9°C | 3.5°C | 0.2°C | 15.7°C | -6.0°C | 99 mm | 90% | 1.5 m/s | 2.2 |
| 1984 | 11.3°C | 6.5°C | 1.6°C | 15.3°C | -1.5°C | 24 mm | 83% | 1.4 m/s | 2.5 |
| 1983 | 6.3°C | 2.5°C | -1.3°C | 13.5°C | -10.3°C | 48 mm | 83% | 1.3 m/s | — |
| 1982 | 10.4°C | 6.7°C | 2.9°C | 18.2°C | -2.5°C | 43 mm | 84% | 1.4 m/s | — |
| 1981 | 8.4°C | 4.6°C | 0.7°C | 16.4°C | -7.1°C | 32 mm | 83% | 1.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 9.3°C with lows near 1.6°C (mean 5.5°C), based on 45 years of NASA POWER data.
September averages 57 mm of rainfall in Fairbanks, a relatively wet time of year. The wettest on record was 102 mm in 1993.
The hottest September reached 19.8°C in 1989. The coldest dipped to -18.9°C in 1992.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.7°C. Daytime highs moved from 8.7°C to 8.9°C and overnight lows from 0.8°C to 2.1°C over the same span.
September is one of the warmer months of the year in Fairbanks and a relatively wet time of year, so plan for around 9.3°C daytime highs and 1.6°C at night.
Not quite — September is the 8th coolest month in Fairbanks, averaging 5.5°C.
For September in Fairbanks, pack warm layers and a jacket for chilly mornings, with typical highs of 9.3°C and lows of 1.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 85% — quite humid.
Average wind speed in September is 1.4 m/s. The windiest September on record averaged 1.6 m/s (1989).
The wettest September on record was 1993 with 102 mm. On average, September sees 57 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 Fairbanks 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.
