September is one of the warmer months of the year in Fresno, with average highs near 34.1°C and lows around 17.9°C (mean 26°C). It is one of the drier months, averaging 6 mm of rainfall and 32% relative humidity across the period.
September is one of the warmer months of the year in Fresno. Across 45 years of records, the warmest September in Fresno was 2022 — when the month averaged 29°C — while the coldest was 1986 at 21.3°C. Typical September days reach 34.1°C with nights near 17.9°C. The long-term trend is warming, about 0.5°C per decade.
September is one of the drier months in Fresno, averaging 6 mm of rainfall. The wettest September on record was 1982 with 44 mm, while the driest were 2010, 2012 and 2020, among others at 0 mm.
Relative humidity in Fresno during September averages 32%. The most humid September was 2025 at 43%, and the least humid was 1988 at 25%.
September receives about 6.1 kWh/m²/day of solar energy in Fresno. The sunniest Septembers were 2003, 2004 and 2010 at 6.4 kWh/m²/day, and the cloudiest was 2020 at 5.1.
Average wind speed in Fresno during September is 1.7 m/s. The windiest September was 2013 at 2.1 m/s, while the calmest were 1984 and 1991 at 1.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 24.8°C | 25.8°C | 26.0°C | 26.5°C | 27.4°C | +2.6°C |
| Avg High | 32.8°C | 34.1°C | 34.3°C | 34.6°C | 35.1°C | +2.3°C |
| Avg Low | 16.7°C | 17.5°C | 17.7°C | 18.4°C | 19.6°C | +2.9°C |
| Avg Rain | 17 mm | 4 mm | 3 mm | 3 mm | 6 mm | -11 mm |
September temperatures in Fresno have risen by about 2.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 7.1°C (1982) to a record high of 47.7°C (2022).
Rainfall in September is one of the drier months, averaging 6 mm, with a wettest year of 44 mm.
One of the best times to visit Fresno
September is one of the best times to visit Fresno. Expect days averaging 34.1°C and nights around 17.9°C (mean 26°C) — warmer than Fresno's yearly average — with low rainfall (6 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 | 34.4°C | 27.2°C | 19.9°C | 42.2°C | 16.4°C | 21 mm | 43% | 1.8 m/s | 5.7 |
| 2024 | 36.0°C | 27.7°C | 19.4°C | 43.0°C | 12.4°C | 1 mm | 31% | 1.7 m/s | 6.1 |
| 2023 | 32.8°C | 25.3°C | 17.9°C | 37.4°C | 13.8°C | 3 mm | 42% | 1.8 m/s | 5.8 |
| 2022 🔥 | 36.5°C | 29.0°C | 21.4°C | 47.7°C | 15.0°C | 11 mm | 33% | 1.9 m/s | 5.8 |
| 2021 | 35.5°C | 27.2°C | 19.0°C | 43.7°C | 13.8°C | 0 mm | 27% | 1.7 m/s | 6 |
| 2020 | 35.3°C | 27.7°C | 20.1°C | 45.2°C | 15.5°C | 0 mm | 29% | 1.6 m/s | 5.1 |
| 2019 | 33.4°C | 25.8°C | 18.2°C | 41.0°C | 10.5°C | 1 mm | 34% | 2 m/s | 6.2 |
| 2018 | 34.9°C | 26.4°C | 17.8°C | 40.1°C | 14.0°C | 0 mm | 27% | 1.7 m/s | 6.3 |
| 2017 | 33.5°C | 26.5°C | 19.5°C | 44.9°C | 10.6°C | 9 mm | 37% | 1.8 m/s | 5.9 |
| 2016 | 33.8°C | 25.5°C | 17.2°C | 41.0°C | 11.2°C | 0 mm | 30% | 1.8 m/s | 6.3 |
| 2015 | 34.8°C | 27.2°C | 19.6°C | 42.3°C | 13.4°C | 4 mm | 28% | 1.6 m/s | 5.8 |
| 2014 | 35.1°C | 27.1°C | 19.1°C | 40.7°C | 13.8°C | 6 mm | 36% | 1.8 m/s | 6.1 |
| 2013 | 32.9°C | 24.9°C | 16.9°C | 40.0°C | 9.0°C | 4 mm | 37% | 2.1 m/s | 6.2 |
| 2012 | 36.5°C | 27.7°C | 18.8°C | 39.3°C | 12.9°C | 0 mm | 26% | 1.7 m/s | 6.2 |
| 2011 | 36.3°C | 27.9°C | 19.4°C | 40.8°C | 13.0°C | 2 mm | 31% | 1.7 m/s | 6.1 |
| 2010 | 34.9°C | 26.2°C | 17.5°C | 42.9°C | 11.9°C | 0 mm | 30% | 1.7 m/s | 6.4 |
| 2009 | 35.9°C | 27.6°C | 19.3°C | 41.7°C | 10.1°C | 2 mm | 30% | 1.9 m/s | 6.1 |
| 2008 | 35.7°C | 26.9°C | 18.1°C | 42.6°C | 12.5°C | 0 mm | 27% | 1.6 m/s | 6.3 |
| 2007 | 31.3°C | 23.9°C | 16.5°C | 42.6°C | 10.5°C | 5 mm | 39% | 1.9 m/s | 6.2 |
| 2006 | 34.3°C | 25.8°C | 17.3°C | 40.8°C | 10.2°C | 2 mm | 28% | 1.6 m/s | 6.3 |
| 2005 | 32.2°C | 24.1°C | 16.1°C | 38.4°C | 11.5°C | 4 mm | 34% | 1.6 m/s | 6.3 |
| 2004 | 34.0°C | 25.6°C | 17.2°C | 42.4°C | 10.1°C | 1 mm | 28% | 1.7 m/s | 6.4 |
| 2003 | 36.2°C | 27.8°C | 19.3°C | 42.7°C | 14.8°C | 1 mm | 30% | 1.7 m/s | 6.4 |
| 2002 | 35.0°C | 26.6°C | 18.1°C | 42.7°C | 11.8°C | 2 mm | 29% | 1.8 m/s | 6 |
| 2001 | 34.9°C | 26.3°C | 17.8°C | 41.2°C | 13.9°C | 3 mm | 33% | 1.8 m/s | 6.3 |
| 2000 | 33.3°C | 25.1°C | 16.9°C | 40.6°C | 11.9°C | 8 mm | 36% | 1.6 m/s | 6.1 |
| 1999 | 35.2°C | 26.6°C | 17.9°C | 38.9°C | 13.5°C | 7 mm | 31% | 1.6 m/s | 6.3 |
| 1998 | 32.6°C | 25.2°C | 17.7°C | 43.6°C | 12.1°C | 14 mm | 42% | 1.8 m/s | 6.1 |
| 1997 | 34.6°C | 26.6°C | 18.7°C | 39.2°C | 14.3°C | 2 mm | 32% | 1.7 m/s | 5.9 |
| 1996 | 33.2°C | 24.7°C | 16.2°C | 39.3°C | 11.6°C | 0 mm | 29% | 1.6 m/s | 6.3 |
| 1995 | 34.6°C | 26.1°C | 17.6°C | 39.5°C | 12.4°C | 0 mm | 32% | 1.9 m/s | 6.3 |
| 1994 | 33.5°C | 25.4°C | 17.3°C | 38.6°C | 12.0°C | 12 mm | 34% | 1.6 m/s | 5.6 |
| 1993 | 34.4°C | 25.7°C | 17.0°C | 40.5°C | 10.8°C | 0 mm | 28% | 1.6 m/s | 6.3 |
| 1992 | 34.2°C | 25.9°C | 17.6°C | 38.3°C | 13.7°C | 1 mm | 29% | 1.6 m/s | 6.1 |
| 1991 | 35.6°C | 27.1°C | 18.6°C | 39.8°C | 11.7°C | 2 mm | 30% | 1.5 m/s | 6.2 |
| 1990 | 33.4°C | 25.1°C | 16.7°C | 38.9°C | 14.2°C | 6 mm | 35% | 1.8 m/s | 6.1 |
| 1989 | 31.7°C | 23.5°C | 15.4°C | 37.9°C | 9.6°C | 41 mm | 40% | 1.7 m/s | 5.9 |
| 1988 | 34.9°C | 26.2°C | 17.5°C | 44.9°C | 12.0°C | 1 mm | 25% | 1.6 m/s | 6 |
| 1987 | 34.7°C | 25.8°C | 16.9°C | 40.5°C | 12.1°C | 2 mm | 29% | 1.9 m/s | 6 |
| 1986 ❄️ | 28.7°C | 21.3°C | 13.8°C | 38.7°C | 8.8°C | 20 mm | 40% | 1.7 m/s | 6 |
| 1985 | 29.7°C | 22.2°C | 14.7°C | 36.3°C | 10.3°C | 12 mm | 40% | 1.7 m/s | 5.7 |
| 1984 | 36.0°C | 27.8°C | 19.6°C | 41.3°C | 12.5°C | 2 mm | 26% | 1.5 m/s | 5.8 |
| 1983 | 34.2°C | 26.4°C | 18.5°C | 41.4°C | 13.5°C | 32 mm | 34% | 1.6 m/s | — |
| 1982 🌧️ | 31.1°C | 23.8°C | 16.4°C | 40.7°C | 7.1°C | 44 mm | 38% | 1.7 m/s | — |
| 1981 | 34.5°C | 26.0°C | 17.5°C | 38.6°C | 12.4°C | 1 mm | 29% | 1.9 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 34.1°C with lows near 17.9°C (mean 26°C), based on 45 years of NASA POWER data.
September averages 6 mm of rainfall in Fresno, one of the drier months. The wettest on record was 44 mm in 1982.
The hottest September reached 47.7°C in 2022. The coldest dipped to 7.1°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.1°C. Daytime highs moved from 33.1°C to 35°C and overnight lows from 17.3°C to 19.5°C over the same span.
September is one of the warmer months of the year in Fresno and one of the drier months, so plan for around 34.1°C daytime highs and 17.9°C at night.
Not quite — September is the 10th coolest month in Fresno, averaging 26°C.
For September in Fresno, pack light, breathable clothing and sun protection, with typical highs of 34.1°C and lows of 17.9°C.
Relative humidity in September averages 32% — relatively dry.
Average wind speed in September is 1.7 m/s. The windiest September on record averaged 2.1 m/s (2013).
The wettest September on record was 1982 with 44 mm. On average, September sees 6 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 Fresno 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.
