September is one of the warmer months of the year in Mission, with average highs near 33.6°C and lows around 23.6°C (mean 28.6°C). It is a relatively wet time of year, averaging 106 mm of rainfall and 71% relative humidity across the period.
September is one of the warmer months of the year in Mission. Across 45 years of records, the warmest September in Mission was 2023 — when the month averaged 32.1°C — while the coldest was 2008 at 26.5°C. Typical September days reach 33.6°C with nights near 23.6°C. The long-term trend is warming, about 0.3°C per decade.
September is a relatively wet time of year in Mission, averaging 106 mm of rainfall. The wettest September on record was 2024 with 261 mm, while the driest was 2023 at 27 mm.
Relative humidity in Mission during September averages 71%. The most humid September was 2003 at 81%, and the least humid was 2011 at 57%.
September receives about 5.4 kWh/m²/day of solar energy in Mission. The sunniest September was 2023 at 6.4 kWh/m²/day, and the cloudiest was 1984 at 4.6.
Average wind speed in Mission during September is 2.7 m/s. The windiest September was 1986 at 3.6 m/s, while the calmest was 2022 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 28.4°C | 28.2°C | 28.2°C | 29.1°C | 29.4°C | +1°C |
| Avg High | 33.6°C | 33.2°C | 33.0°C | 34.0°C | 34.6°C | +1°C |
| Avg Low | 23.2°C | 23.2°C | 23.3°C | 24.2°C | 24.2°C | +1°C |
| Avg Rain | 74 mm | 103 mm | 132 mm | 114 mm | 106 mm | +32 mm |
September temperatures in Mission have risen by about 1.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 13.3°C (2020) to a record high of 42.1°C (2000).
Rainfall in September is a relatively wet time of year, averaging 106 mm, with a wettest year of 261 mm.
A quieter season to visit Mission
If your dates are flexible, the more temperate months of March and November tend to be the most comfortable for visiting Mission. That said, September — with days averaging 33.6°C and nights around 23.6°C (mean 28.6°C) and higher rainfall (106 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 34.6°C | 29.6°C | 24.7°C | 39.6°C | 21.2°C | 99 mm | 71% | 2.3 m/s | 5.6 |
| 2024 🌧️ | 33.3°C | 28.8°C | 24.2°C | 36.0°C | 19.4°C | 261 mm | 77% | 2.4 m/s | 5.2 |
| 2023 🔥 | 38.4°C | 32.1°C | 25.9°C | 40.6°C | 23.7°C | 27 mm | 62% | 2.8 m/s | 6.4 |
| 2022 | 33.5°C | 28.5°C | 23.5°C | 35.8°C | 17.9°C | 95 mm | 72% | 2 m/s | 5.5 |
| 2021 | 34.3°C | 29.2°C | 24.0°C | 38.0°C | 17.9°C | 58 mm | 69% | 2.6 m/s | 5.9 |
| 2020 | 33.2°C | 28.1°C | 23.1°C | 37.6°C | 13.3°C | 95 mm | 71% | 2.9 m/s | 5.2 |
| 2019 | 34.3°C | 29.8°C | 25.3°C | 38.0°C | 23.9°C | 101 mm | 72% | 3 m/s | 5.5 |
| 2018 | 32.3°C | 28.4°C | 24.5°C | 38.7°C | 20.7°C | 173 mm | 78% | 2.4 m/s | 5 |
| 2017 | 35.0°C | 29.6°C | 24.2°C | 37.9°C | 19.6°C | 43 mm | 65% | 3.1 m/s | 5.4 |
| 2016 | 34.9°C | 29.8°C | 24.8°C | 38.2°C | 20.6°C | 83 mm | 69% | 2.7 m/s | 5.7 |
| 2015 | 34.3°C | 29.1°C | 23.9°C | 37.8°C | 20.4°C | 92 mm | 72% | 2.7 m/s | 5.7 |
| 2014 | 31.7°C | 27.9°C | 24.0°C | 37.2°C | 21.0°C | 228 mm | 80% | 2.7 m/s | 4.9 |
| 2013 | 32.4°C | 28.1°C | 23.9°C | 38.5°C | 18.1°C | 171 mm | 75% | 2.7 m/s | 4.9 |
| 2012 | 35.8°C | 29.8°C | 23.9°C | 40.2°C | 20.4°C | 35 mm | 62% | 3.2 m/s | 5.9 |
| 2011 | 37.0°C | 30.5°C | 24.0°C | 40.9°C | 20.1°C | 35 mm | 57% | 2.8 m/s | 6.3 |
| 2010 | 32.1°C | 27.9°C | 23.7°C | 36.3°C | 15.1°C | 175 mm | 77% | 2.5 m/s | 5.2 |
| 2009 | 32.9°C | 28.1°C | 23.3°C | 37.9°C | 16.4°C | 161 mm | 73% | 2.4 m/s | 4.9 |
| 2008 ❄️ | 31.3°C | 26.5°C | 21.8°C | 36.6°C | 16.9°C | 125 mm | 75% | 2.4 m/s | 5.3 |
| 2007 | 32.3°C | 28.0°C | 23.7°C | 35.3°C | 21.0°C | 78 mm | 78% | 2.2 m/s | 5.5 |
| 2006 | 32.9°C | 28.2°C | 23.5°C | 38.4°C | 18.0°C | 228 mm | 74% | 2.8 m/s | 5.3 |
| 2005 | 35.6°C | 30.4°C | 25.2°C | 41.0°C | 23.9°C | 51 mm | 67% | 2.8 m/s | 5.7 |
| 2004 | 32.9°C | 28.3°C | 23.7°C | 36.4°C | 21.1°C | 109 mm | 73% | 2.3 m/s | 5.2 |
| 2003 | 30.9°C | 27.2°C | 23.5°C | 34.6°C | 19.9°C | 257 mm | 81% | 2.4 m/s | 4.7 |
| 2002 | 32.7°C | 27.8°C | 22.8°C | 36.1°C | 17.4°C | 177 mm | 73% | 2.7 m/s | 5.3 |
| 2001 | 32.8°C | 27.8°C | 22.7°C | 38.0°C | 16.1°C | 103 mm | 73% | 2.8 m/s | 5.7 |
| 2000 | 35.3°C | 29.2°C | 23.1°C | 42.1°C | 14.6°C | 36 mm | 61% | 3 m/s | 5.9 |
| 1999 | 33.7°C | 28.1°C | 22.5°C | 37.4°C | 16.8°C | 101 mm | 69% | 2.7 m/s | 5.7 |
| 1998 | 32.5°C | 28.4°C | 24.2°C | 37.9°C | 22.2°C | 225 mm | 78% | 2.7 m/s | 4.8 |
| 1997 | 34.2°C | 28.9°C | 23.6°C | 38.1°C | 18.8°C | 81 mm | 69% | 2.4 m/s | 5.7 |
| 1996 | 33.8°C | 28.7°C | 23.6°C | 38.9°C | 14.4°C | 61 mm | 70% | 2.9 m/s | 5.8 |
| 1995 | 33.6°C | 28.4°C | 23.2°C | 37.4°C | 13.6°C | 122 mm | 71% | 2.4 m/s | 5.7 |
| 1994 | 33.5°C | 27.9°C | 22.3°C | 37.9°C | 16.5°C | 73 mm | 66% | 2.4 m/s | 5.4 |
| 1993 | 32.7°C | 27.9°C | 23.0°C | 38.0°C | 14.7°C | 119 mm | 73% | 2.7 m/s | 5.5 |
| 1992 | 34.0°C | 28.7°C | 23.4°C | 39.3°C | 15.5°C | 64 mm | 67% | 3.1 m/s | 5.4 |
| 1991 | 31.4°C | 27.0°C | 22.7°C | 35.5°C | 14.6°C | 95 mm | 74% | 2.6 m/s | 5 |
| 1990 | 32.7°C | 28.0°C | 23.4°C | 36.1°C | 17.5°C | 91 mm | 71% | 2.5 m/s | 5.3 |
| 1989 | 33.6°C | 27.8°C | 22.0°C | 37.9°C | 14.1°C | 59 mm | 62% | 2.8 m/s | 6 |
| 1988 | 33.4°C | 28.2°C | 23.0°C | 36.0°C | 19.2°C | 142 mm | 71% | 3.3 m/s | 5.3 |
| 1987 | 34.6°C | 29.0°C | 23.3°C | 38.9°C | 18.0°C | 58 mm | 65% | 3 m/s | 5.5 |
| 1986 | 34.7°C | 29.8°C | 24.8°C | 36.7°C | 23.0°C | 52 mm | 68% | 3.6 m/s | 5.5 |
| 1985 | 33.8°C | 28.8°C | 23.8°C | 38.1°C | 13.5°C | 84 mm | 68% | 3.2 m/s | 5.7 |
| 1984 | 31.4°C | 26.9°C | 22.3°C | 36.5°C | 13.6°C | 122 mm | 72% | 3.4 m/s | 4.6 |
| 1983 | 32.8°C | 28.0°C | 23.3°C | 38.6°C | 15.3°C | 82 mm | 71% | 3.1 m/s | — |
| 1982 | 35.1°C | 29.3°C | 23.4°C | 38.9°C | 19.6°C | 29 mm | 63% | 2.9 m/s | — |
| 1981 | 32.9°C | 27.9°C | 22.9°C | 35.0°C | 15.8°C | 36 mm | 71% | 2.6 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 33.6°C with lows near 23.6°C (mean 28.6°C), based on 45 years of NASA POWER data.
September averages 106 mm of rainfall in Mission, a relatively wet time of year. The wettest on record was 261 mm in 2024.
The hottest September reached 42.1°C in 2000. The coldest dipped to 13.3°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.4°C. Daytime highs moved from 33.2°C to 34.8°C and overnight lows from 23.1°C to 24.5°C over the same span.
September is one of the warmer months of the year in Mission and a relatively wet time of year, so plan for around 33.6°C daytime highs and 23.6°C at night.
Not quite — September is the 8th coolest month in Mission, averaging 28.6°C.
For September in Mission, pack light, breathable clothing and sun protection, with typical highs of 33.6°C and lows of 23.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 71% — moderately humid.
Average wind speed in September is 2.7 m/s. The windiest September on record averaged 3.6 m/s (1986).
The wettest September on record was 2024 with 261 mm. On average, September sees 106 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 Mission 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.
