September is one of the warmer months of the year in Spokane, with average highs near 22.7°C and lows around 8.6°C (mean 15.7°C). It is one of the drier months, averaging 23 mm of rainfall and 55% relative humidity across the period.
September is one of the warmer months of the year in Spokane. Across 45 years of records, the warmest September in Spokane was 2025 — when the month averaged 19.6°C — while the coldest was 1985 at 11.5°C. Typical September days reach 22.7°C with nights near 8.6°C. The long-term trend is warming, about 0.6°C per decade.
September is one of the drier months in Spokane, averaging 23 mm of rainfall. The wettest September on record was 2013 with 70 mm, while the driest were 1990 and 2012 at 1 mm.
Relative humidity in Spokane during September averages 55%. The most humid September was 2019 at 65%, and the least humid was 2001 at 43%.
September receives about 4.4 kWh/m²/day of solar energy in Spokane. The sunniest September was 1990 at 5.2 kWh/m²/day, and the cloudiest was 1986 at 3.5.
Average wind speed in Spokane during September is 1.8 m/s. The windiest September was 1992 at 2.3 m/s, while the calmest was 1990 at 1.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.0°C | 15.9°C | 15.6°C | 15.7°C | 17.5°C | +3.5°C |
| Avg High | 20.9°C | 23.1°C | 22.8°C | 22.5°C | 24.5°C | +3.6°C |
| Avg Low | 7.1°C | 8.7°C | 8.5°C | 8.8°C | 10.5°C | +3.4°C |
| Avg Rain | 32 mm | 18 mm | 21 mm | 23 mm | 20 mm | -12 mm |
September temperatures in Spokane have risen by about 4.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -3.1°C (2000) to a record high of 37.5°C (1988).
Rainfall in September is one of the drier months, averaging 23 mm, with a wettest year of 70 mm.
One of the best times to visit Spokane
September is one of the best times to visit Spokane. Expect days averaging 22.7°C and nights around 8.6°C (mean 15.7°C) — warmer than Spokane's yearly average — with low rainfall (23 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 🔥 | 26.8°C | 19.6°C | 12.3°C | 36.2°C | 5.5°C | 12 mm | 53% | 1.5 m/s | 4.4 |
| 2024 | 25.1°C | 17.9°C | 10.8°C | 35.1°C | 1.3°C | 14 mm | 54% | 1.9 m/s | 4.3 |
| 2023 | 22.5°C | 16.0°C | 9.6°C | 30.7°C | 3.4°C | 26 mm | 57% | 1.7 m/s | 4 |
| 2022 | 25.1°C | 17.9°C | 10.7°C | 35.0°C | 6.3°C | 21 mm | 53% | 1.7 m/s | 4.3 |
| 2021 | 23.1°C | 16.3°C | 9.4°C | 31.9°C | 4.0°C | 34 mm | 51% | 1.9 m/s | 4.3 |
| 2020 | 24.3°C | 17.2°C | 10.0°C | 33.9°C | 4.3°C | 13 mm | 51% | 1.8 m/s | 4.1 |
| 2019 | 20.3°C | 14.5°C | 8.6°C | 31.2°C | -1.8°C | 42 mm | 65% | 1.9 m/s | 3.6 |
| 2018 | 21.3°C | 14.6°C | 7.9°C | 29.9°C | 4.5°C | 4 mm | 53% | 1.8 m/s | 4.5 |
| 2017 | 22.6°C | 16.0°C | 9.4°C | 33.4°C | 2.0°C | 25 mm | 56% | 1.8 m/s | 3.9 |
| 2016 | 21.4°C | 14.6°C | 7.8°C | 28.4°C | 3.9°C | 19 mm | 58% | 1.9 m/s | 4.3 |
| 2015 | 21.7°C | 14.7°C | 7.8°C | 31.6°C | 4.1°C | 17 mm | 52% | 1.7 m/s | 4.2 |
| 2014 | 23.9°C | 16.6°C | 9.3°C | 31.4°C | 2.5°C | 16 mm | 53% | 2 m/s | 4.6 |
| 2013 🌧️ | 22.6°C | 16.6°C | 10.7°C | 33.2°C | 4.5°C | 70 mm | 64% | 2.2 m/s | 3.6 |
| 2012 | 24.7°C | 16.9°C | 9.0°C | 30.4°C | 4.2°C | 1 mm | 50% | 1.5 m/s | 5 |
| 2011 | 25.5°C | 17.5°C | 9.5°C | 33.3°C | 4.1°C | 8 mm | 51% | 1.8 m/s | 4.8 |
| 2010 | 21.3°C | 14.8°C | 8.3°C | 29.4°C | 3.4°C | 29 mm | 64% | 1.9 m/s | 4 |
| 2009 | 24.6°C | 17.1°C | 9.7°C | 32.2°C | 1.8°C | 8 mm | 50% | 1.9 m/s | 4.8 |
| 2008 | 23.3°C | 15.7°C | 8.1°C | 32.0°C | 1.0°C | 17 mm | 50% | 1.6 m/s | 4.8 |
| 2007 | 22.2°C | 15.0°C | 7.9°C | 29.7°C | -0.2°C | 13 mm | 51% | 1.9 m/s | 4.7 |
| 2006 | 23.4°C | 16.0°C | 8.5°C | 34.0°C | 2.5°C | 16 mm | 52% | 1.5 m/s | 4.5 |
| 2005 | 20.9°C | 14.3°C | 7.8°C | 28.6°C | 2.9°C | 32 mm | 51% | 1.8 m/s | 4.4 |
| 2004 | 20.5°C | 14.3°C | 8.1°C | 27.1°C | 2.7°C | 31 mm | 63% | 1.8 m/s | 3.9 |
| 2003 | 24.0°C | 16.8°C | 9.6°C | 35.5°C | 4.0°C | 27 mm | 49% | 2 m/s | 4.5 |
| 2002 | 22.8°C | 15.5°C | 8.3°C | 33.6°C | 2.9°C | 11 mm | 48% | 1.8 m/s | 4.4 |
| 2001 | 25.7°C | 17.8°C | 9.8°C | 32.4°C | 3.5°C | 10 mm | 43% | 1.8 m/s | 4.9 |
| 2000 | 20.7°C | 14.0°C | 7.2°C | 33.0°C | -3.1°C | 47 mm | 59% | 2 m/s | 3.7 |
| 1999 | 22.7°C | 14.9°C | 7.0°C | 28.9°C | -1.0°C | 2 mm | 48% | 1.8 m/s | 4.9 |
| 1998 | 25.4°C | 18.4°C | 11.4°C | 33.7°C | 6.5°C | 22 mm | 55% | 1.5 m/s | 4.7 |
| 1997 | 22.5°C | 15.8°C | 9.0°C | 30.6°C | 4.1°C | 43 mm | 64% | 2 m/s | 4.1 |
| 1996 | 19.6°C | 13.1°C | 6.7°C | 32.4°C | -0.3°C | 23 mm | 62% | 1.7 m/s | 4 |
| 1995 | 22.9°C | 16.1°C | 9.2°C | 32.0°C | 1.7°C | 45 mm | 59% | 1.7 m/s | 4.5 |
| 1994 | 25.1°C | 17.6°C | 10.1°C | 31.4°C | 5.5°C | 15 mm | 45% | 1.7 m/s | 4.6 |
| 1993 | 22.1°C | 14.9°C | 7.7°C | 29.1°C | 2.1°C | 8 mm | 56% | 1.6 m/s | 4.9 |
| 1992 | 20.4°C | 13.6°C | 6.8°C | 28.5°C | 3.1°C | 23 mm | 56% | 2.3 m/s | 4.3 |
| 1991 | 23.9°C | 16.3°C | 8.7°C | 29.5°C | 2.7°C | 2 mm | 50% | 1.7 m/s | 4.9 |
| 1990 | 26.7°C | 18.6°C | 10.5°C | 32.2°C | 5.8°C | 1 mm | 48% | 1.4 m/s | 5.2 |
| 1989 | 23.3°C | 15.5°C | 7.7°C | 28.5°C | 4.6°C | 8 mm | 52% | 1.7 m/s | 5 |
| 1988 | 22.5°C | 15.1°C | 7.8°C | 37.5°C | 1.4°C | 32 mm | 51% | 1.9 m/s | 4.1 |
| 1987 | 25.1°C | 17.3°C | 9.5°C | 33.3°C | 2.8°C | 4 mm | 46% | 1.6 m/s | 5 |
| 1986 | 17.7°C | 12.0°C | 6.4°C | 29.1°C | 2.5°C | 59 mm | 65% | 2 m/s | 3.5 |
| 1985 ❄️ | 17.7°C | 11.5°C | 5.2°C | 24.2°C | -2.4°C | 55 mm | 62% | 2.1 m/s | 3.9 |
| 1984 | 19.5°C | 12.6°C | 5.7°C | 29.0°C | -3.0°C | 36 mm | 58% | 2.1 m/s | 4.2 |
| 1983 | 18.8°C | 12.2°C | 5.5°C | 25.0°C | -1.8°C | 22 mm | 62% | 2 m/s | — |
| 1982 | 20.8°C | 14.2°C | 7.5°C | 29.7°C | 1.0°C | 50 mm | 62% | 1.9 m/s | — |
| 1981 | 22.4°C | 15.3°C | 8.2°C | 33.5°C | 1.4°C | 21 mm | 54% | 1.8 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 22.7°C with lows near 8.6°C (mean 15.7°C), based on 45 years of NASA POWER data.
September averages 23 mm of rainfall in Spokane, one of the drier months. The wettest on record was 70 mm in 2013.
The hottest September reached 37.5°C in 1988. The coldest dipped to -3.1°C in 2000.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 4.3°C. Daytime highs moved from 19.8°C to 24.5°C and overnight lows from 6.4°C to 10.6°C over the same span.
September is one of the warmer months of the year in Spokane and one of the drier months, so plan for around 22.7°C daytime highs and 8.6°C at night.
Not quite — September is the 9th coolest month in Spokane, averaging 15.7°C.
For September in Spokane, pack light layers you can adjust through the day, with typical highs of 22.7°C and lows of 8.6°C.
Relative humidity in September averages 55% — relatively dry.
Average wind speed in September is 1.8 m/s. The windiest September on record averaged 2.3 m/s (1992).
The wettest September on record was 2013 with 70 mm. On average, September sees 23 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 Spokane 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.
