September is one of the warmer months of the year in Stockton, with average highs near 33°C and lows around 14.2°C (mean 23.6°C). It is one of the drier months, averaging 6 mm of rainfall and 48% relative humidity across the period.
September is one of the warmer months of the year in Stockton. Across 45 years of records, the warmest September in Stockton was 2022 — when the month averaged 25.7°C — while the coldest was 1986 at 19.8°C. Typical September days reach 33°C with nights near 14.2°C. The long-term trend is warming, about 0.4°C per decade.
September is one of the drier months in Stockton, averaging 6 mm of rainfall. The wettest September on record was 1989 with 52 mm, while the driest were 2018, 2020 and 2024, among others at 0 mm.
Relative humidity in Stockton during September averages 48%. The most humid September was 2023 at 57%, and the least humid was 1984 at 35%.
September receives about 5.9 kWh/m²/day of solar energy in Stockton. The sunniest September was 2018 at 6.3 kWh/m²/day, and the cloudiest was 2020 at 5.4.
Average wind speed in Stockton during September is 2.2 m/s. The windiest September was 2013 at 2.5 m/s, while the calmest were 1983 and 2000 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.7°C | 23.7°C | 23.5°C | 23.8°C | 24.7°C | +2°C |
| Avg High | 31.9°C | 33.3°C | 33.0°C | 33.0°C | 33.9°C | +2°C |
| Avg Low | 13.4°C | 14.0°C | 13.9°C | 14.6°C | 15.5°C | +2.1°C |
| Avg Rain | 20 mm | 2 mm | 3 mm | 3 mm | 4 mm | -15 mm |
September temperatures in Stockton have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 7.8°C (1986) to a record high of 48.6°C (2022).
Rainfall in September is one of the drier months, averaging 6 mm, with a wettest year of 52 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.
One of the best times to visit Stockton
September is one of the best times to visit Stockton. Expect days averaging 33°C and nights around 14.2°C (mean 23.6°C) — warmer than Stockton'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 | 33.6°C | 25.0°C | 16.4°C | 41.7°C | 13.4°C | 6 mm | 54% | 2.4 m/s | 5.5 |
| 2024 | 34.5°C | 24.8°C | 15.0°C | 41.5°C | 11.6°C | 0 mm | 48% | 2.3 m/s | 6 |
| 2023 | 31.4°C | 22.9°C | 14.3°C | 36.5°C | 11.4°C | 3 mm | 57% | 2.4 m/s | 5.7 |
| 2022 🔥 | 34.7°C | 25.7°C | 16.7°C | 48.6°C | 12.6°C | 14 mm | 47% | 2.3 m/s | 5.7 |
| 2021 | 34.2°C | 24.5°C | 14.7°C | 41.6°C | 11.2°C | 2 mm | 44% | 2.3 m/s | 6.1 |
| 2020 | 34.7°C | 25.4°C | 16.1°C | 45.9°C | 13.0°C | 0 mm | 47% | 2.1 m/s | 5.4 |
| 2019 | 31.9°C | 23.4°C | 15.0°C | 39.8°C | 9.1°C | 8 mm | 51% | 2.2 m/s | 6.1 |
| 2018 | 32.8°C | 23.0°C | 13.2°C | 37.3°C | 10.0°C | 0 mm | 48% | 2.3 m/s | 6.3 |
| 2017 | 33.0°C | 24.8°C | 16.6°C | 45.3°C | 9.3°C | 2 mm | 47% | 2.1 m/s | 5.6 |
| 2016 | 32.7°C | 23.3°C | 14.0°C | 40.1°C | 9.4°C | 0 mm | 46% | 2.3 m/s | 6.2 |
| 2015 | 32.8°C | 24.2°C | 15.6°C | 41.7°C | 11.4°C | 2 mm | 43% | 2.2 m/s | 5.6 |
| 2014 | 33.0°C | 24.1°C | 15.2°C | 39.4°C | 11.8°C | 11 mm | 55% | 2.3 m/s | 6 |
| 2013 | 31.0°C | 22.5°C | 13.9°C | 39.0°C | 9.5°C | 11 mm | 54% | 2.5 m/s | 6 |
| 2012 | 34.1°C | 23.6°C | 13.2°C | 38.3°C | 10.5°C | 0 mm | 47% | 2.4 m/s | 6.1 |
| 2011 | 34.8°C | 24.9°C | 15.1°C | 40.1°C | 10.9°C | 1 mm | 46% | 2.2 m/s | 6 |
| 2010 | 33.5°C | 23.7°C | 13.9°C | 41.6°C | 10.1°C | 0 mm | 47% | 2.1 m/s | 6.1 |
| 2009 | 34.1°C | 24.6°C | 15.0°C | 40.5°C | 9.8°C | 7 mm | 47% | 2.3 m/s | 6 |
| 2008 | 34.4°C | 24.1°C | 13.9°C | 41.7°C | 10.5°C | 0 mm | 44% | 2 m/s | 6.2 |
| 2007 | 30.1°C | 21.8°C | 13.5°C | 40.6°C | 9.0°C | 5 mm | 53% | 2.2 m/s | 5.8 |
| 2006 | 32.7°C | 23.0°C | 13.4°C | 38.5°C | 9.7°C | 1 mm | 46% | 2.2 m/s | 6.1 |
| 2005 | 31.0°C | 21.7°C | 12.3°C | 37.0°C | 9.7°C | 3 mm | 50% | 2.1 m/s | 6.2 |
| 2004 | 33.3°C | 23.8°C | 14.3°C | 41.7°C | 9.3°C | 4 mm | 42% | 2.1 m/s | 6.2 |
| 2003 | 34.4°C | 24.7°C | 15.0°C | 41.4°C | 12.3°C | 1 mm | 46% | 2.2 m/s | 6.1 |
| 2002 | 33.9°C | 24.0°C | 14.2°C | 41.7°C | 10.4°C | 1 mm | 44% | 2.2 m/s | 6.1 |
| 2001 | 33.4°C | 23.5°C | 13.6°C | 39.7°C | 11.3°C | 5 mm | 50% | 2.3 m/s | 6.1 |
| 2000 | 32.7°C | 23.4°C | 14.2°C | 41.0°C | 10.3°C | 5 mm | 47% | 1.9 m/s | 5.7 |
| 1999 | 34.5°C | 24.3°C | 14.0°C | 38.8°C | 11.4°C | 2 mm | 44% | 2.2 m/s | 6.1 |
| 1998 | 32.4°C | 23.7°C | 14.9°C | 43.4°C | 11.0°C | 7 mm | 51% | 2.3 m/s | 5.7 |
| 1997 | 34.2°C | 24.9°C | 15.7°C | 40.1°C | 12.0°C | 1 mm | 46% | 2.2 m/s | 6.1 |
| 1996 | 32.1°C | 22.3°C | 12.6°C | 37.7°C | 10.7°C | 3 mm | 47% | 2.1 m/s | 5.9 |
| 1995 | 33.1°C | 23.3°C | 13.5°C | 39.4°C | 11.2°C | 0 mm | 51% | 2.4 m/s | 6 |
| 1994 | 32.6°C | 23.2°C | 13.8°C | 38.4°C | 10.8°C | 3 mm | 50% | 2 m/s | 5.7 |
| 1993 | 33.6°C | 23.5°C | 13.4°C | 39.4°C | 9.4°C | 2 mm | 44% | 2 m/s | 6 |
| 1992 | 33.6°C | 23.8°C | 14.0°C | 37.1°C | 10.8°C | 0 mm | 45% | 2.2 m/s | 6 |
| 1991 | 34.4°C | 24.2°C | 13.9°C | 39.7°C | 10.5°C | 1 mm | 47% | 2 m/s | 6 |
| 1990 | 33.0°C | 23.4°C | 13.7°C | 37.8°C | 12.2°C | 4 mm | 51% | 2.2 m/s | 6.1 |
| 1989 🌧️ | 30.2°C | 21.2°C | 12.3°C | 37.3°C | 9.2°C | 52 mm | 55% | 2 m/s | 5.8 |
| 1988 | 34.3°C | 23.8°C | 13.2°C | 45.6°C | 10.4°C | 0 mm | 39% | 2.1 m/s | 5.9 |
| 1987 | 33.9°C | 23.7°C | 13.4°C | 40.0°C | 11.0°C | 0 mm | 45% | 2.2 m/s | 5.9 |
| 1986 ❄️ | 28.0°C | 19.8°C | 11.5°C | 37.2°C | 7.8°C | 29 mm | 55% | 2.2 m/s | 5.6 |
| 1985 | 29.1°C | 20.6°C | 12.1°C | 36.1°C | 9.3°C | 12 mm | 53% | 2 m/s | 5.5 |
| 1984 | 35.2°C | 25.6°C | 16.1°C | 40.2°C | 10.1°C | 2 mm | 35% | 2 m/s | 5.8 |
| 1983 | 33.5°C | 24.3°C | 15.0°C | 41.3°C | 12.1°C | 28 mm | 48% | 1.9 m/s | — |
| 1982 | 30.3°C | 21.8°C | 13.3°C | 40.2°C | 8.7°C | 49 mm | 49% | 2.1 m/s | — |
| 1981 | 33.0°C | 23.4°C | 13.8°C | 38.1°C | 10.9°C | 3 mm | 44% | 2.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 33°C with lows near 14.2°C (mean 23.6°C), based on 45 years of NASA POWER data.
September averages 6 mm of rainfall in Stockton, one of the drier months. The wettest on record was 52 mm in 1989.
The hottest September reached 48.6°C in 2022. The coldest dipped to 7.8°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.5°C. Daytime highs moved from 32.2°C to 33.7°C and overnight lows from 14.1°C to 15.4°C over the same span.
September is one of the warmer months of the year in Stockton and one of the drier months, so plan for around 33°C daytime highs and 14.2°C at night.
Not quite — September is the 10th coolest month in Stockton, averaging 23.6°C.
For September in Stockton, pack light, breathable clothing and sun protection, with typical highs of 33°C and lows of 14.2°C.
Relative humidity in September averages 48% — relatively dry.
Average wind speed in September is 2.2 m/s. The windiest September on record averaged 2.5 m/s (2013).
The wettest September on record was 1989 with 52 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 Stockton 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.
