March is one of the cooler months of the year in Simi Valley, with average highs near 18.5°C and lows around 4.9°C (mean 11.7°C). It is a relatively wet time of year, averaging 65 mm of rainfall and 65% relative humidity across the period.
March is one of the cooler months of the year in Simi Valley. Across 45 years of records, the warmest Marchs in Simi Valley were 2004 and 2015 — when the month averaged 15.9°C — while the coldest was 2006 at 7.9°C. Typical March days reach 18.5°C with nights near 4.9°C. The long-term trend is warming, about 0.2°C per decade.
March is a relatively wet time of year in Simi Valley, averaging 65 mm of rainfall. The wettest March on record was 1991 with 195 mm, while the driest was 1997 at 1 mm.
Relative humidity in Simi Valley during March averages 65%. The most humid March was 1983 at 80%, and the least humid was 2015 at 51%.
March receives about 5.2 kWh/m²/day of solar energy in Simi Valley. The sunniest March was 2008 at 6 kWh/m²/day, and the cloudiest was 1992 at 4.3.
Average wind speed in Simi Valley during March is 2.5 m/s. The windiest March was 1984 at 3.3 m/s, while the calmest were 1996, 2006 and 2015, among others at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.2°C | 11.5°C | 12.0°C | 12.7°C | 10.9°C | -0.3°C |
| Avg High | 17.9°C | 18.0°C | 19.2°C | 19.7°C | 17.2°C | -0.7°C |
| Avg Low | 4.5°C | 5.0°C | 4.9°C | 5.6°C | 4.6°C | +0.1°C |
| Avg Rain | 67 mm | 86 mm | 38 mm | 56 mm | 86 mm | +19 mm |
March temperatures in Simi Valley have risen by about 0.6°C between 1981–1985 and 2021–2025.
March has ranged from a record low of -3.1°C (2006) to a record high of 30.5°C (2013).
Rainfall in March is a relatively wet time of year, averaging 65 mm, with a wettest year of 195 mm.
A quieter season to visit Simi Valley
If your dates are flexible, the more temperate months of June and September tend to be the most comfortable for visiting Simi Valley. That said, March — with days averaging 18.5°C and nights around 4.9°C (mean 11.7°C) and moderate rainfall (65 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 17.9°C | 11.4°C | 5.0°C | 29.6°C | 0.3°C | 54 mm | 70% | 2.5 m/s | 5 |
| 2024 | 16.7°C | 11.0°C | 5.4°C | 23.0°C | 2.3°C | 106 mm | 76% | 2.3 m/s | 5.1 |
| 2023 | 13.8°C | 8.6°C | 3.4°C | 18.8°C | -1.8°C | 172 mm | 77% | 2.6 m/s | 4.6 |
| 2022 | 20.9°C | 13.5°C | 6.2°C | 29.0°C | -1.2°C | 37 mm | 58% | 2.4 m/s | 5.7 |
| 2021 | 18.1°C | 10.6°C | 3.0°C | 27.7°C | -1.6°C | 24 mm | 59% | 2.2 m/s | 5.6 |
| 2020 | 16.0°C | 10.3°C | 4.7°C | 23.9°C | -0.4°C | 125 mm | 74% | 2.2 m/s | 4.5 |
| 2019 | 17.1°C | 11.1°C | 5.1°C | 24.0°C | 0.5°C | 84 mm | 72% | 2.3 m/s | 5.2 |
| 2018 | 17.8°C | 11.5°C | 5.2°C | 27.5°C | -1.2°C | 131 mm | 65% | 2.2 m/s | 4.9 |
| 2017 | 20.8°C | 13.7°C | 6.5°C | 28.0°C | -2.5°C | 13 mm | 63% | 2.4 m/s | 5.7 |
| 2016 | 20.9°C | 13.5°C | 6.0°C | 27.6°C | 0.9°C | 54 mm | 63% | 2.5 m/s | 5.5 |
| 2015 | 23.6°C | 15.9°C | 8.3°C | 29.7°C | 2.0°C | 13 mm | 51% | 2.1 m/s | 5.7 |
| 2014 | 20.7°C | 13.6°C | 6.5°C | 28.1°C | 3.2°C | 31 mm | 57% | 2.3 m/s | 5.5 |
| 2013 | 21.6°C | 13.8°C | 6.0°C | 30.5°C | 1.1°C | 19 mm | 55% | 2.2 m/s | 5.5 |
| 2012 | 18.9°C | 11.4°C | 3.8°C | 26.6°C | -2.6°C | 65 mm | 57% | 2.3 m/s | 5.4 |
| 2011 | 17.5°C | 11.2°C | 4.9°C | 29.3°C | 1.2°C | 135 mm | 71% | 2.7 m/s | 5 |
| 2010 | 17.8°C | 10.9°C | 4.0°C | 24.9°C | -1.4°C | 13 mm | 64% | 2.4 m/s | 5.6 |
| 2009 | 18.6°C | 11.1°C | 3.6°C | 25.8°C | -2.3°C | 13 mm | 63% | 2.3 m/s | 5.6 |
| 2008 | 19.5°C | 12.0°C | 4.5°C | 26.2°C | -0.1°C | 1 mm | 59% | 2.8 m/s | 6 |
| 2007 | 22.6°C | 14.3°C | 6.1°C | 30.4°C | -1.9°C | 5 mm | 52% | 2.3 m/s | 5.7 |
| 2006 ❄️ | 14.1°C | 7.9°C | 1.7°C | 23.2°C | -3.1°C | 81 mm | 72% | 2.1 m/s | 4.8 |
| 2005 | 17.7°C | 11.7°C | 5.7°C | 26.1°C | 1.0°C | 47 mm | 72% | 2.3 m/s | 5.1 |
| 2004 🔥 | 23.7°C | 15.9°C | 8.1°C | 29.3°C | 2.3°C | 13 mm | 56% | 2.4 m/s | 5.8 |
| 2003 | 19.1°C | 11.9°C | 4.7°C | 25.8°C | 0.1°C | 61 mm | 65% | 2.8 m/s | 5.7 |
| 2002 | 18.7°C | 11.2°C | 3.8°C | 28.7°C | -0.8°C | 12 mm | 54% | 2.5 m/s | 5.7 |
| 2001 | 19.1°C | 12.6°C | 6.1°C | 26.3°C | 1.5°C | 93 mm | 72% | 2.4 m/s | 5.2 |
| 2000 | 18.4°C | 11.6°C | 4.7°C | 25.4°C | 1.2°C | 48 mm | 68% | 2.5 m/s | 5.3 |
| 1999 | 16.6°C | 9.8°C | 3.0°C | 25.8°C | -1.0°C | 43 mm | 69% | 2.6 m/s | 5 |
| 1998 | 17.1°C | 11.0°C | 5.0°C | 25.2°C | -0.4°C | 96 mm | 73% | 2.4 m/s | 5.1 |
| 1997 | 22.1°C | 14.0°C | 5.9°C | 28.2°C | -0.4°C | 1 mm | 57% | 2.4 m/s | 5.6 |
| 1996 | 19.3°C | 12.2°C | 5.0°C | 26.7°C | 0.8°C | 42 mm | 65% | 2.1 m/s | 5.2 |
| 1995 | 16.4°C | 10.9°C | 5.3°C | 23.3°C | 0.0°C | 189 mm | 74% | 2.6 m/s | 4.9 |
| 1994 | 20.0°C | 12.8°C | 5.5°C | 27.0°C | 0.1°C | 52 mm | 63% | 2.1 m/s | 5.3 |
| 1993 | 19.3°C | 12.8°C | 6.3°C | 25.3°C | 0.0°C | 89 mm | 71% | 2.4 m/s | 5.1 |
| 1992 | 15.8°C | 11.1°C | 6.3°C | 22.6°C | 2.7°C | 144 mm | 80% | 2.1 m/s | 4.3 |
| 1991 🌧️ | 13.9°C | 8.1°C | 2.3°C | 21.5°C | -3.0°C | 195 mm | 72% | 2.9 m/s | 4.8 |
| 1990 | 19.8°C | 12.4°C | 4.9°C | 27.6°C | -2.6°C | 5 mm | 58% | 2.3 m/s | 5.1 |
| 1989 | 19.8°C | 12.6°C | 5.4°C | 27.7°C | -1.8°C | 19 mm | 65% | 3.2 m/s | 5.2 |
| 1988 | 20.6°C | 12.5°C | 4.5°C | 30.1°C | -0.9°C | 3 mm | 53% | 3.1 m/s | 5.7 |
| 1987 | 18.0°C | 10.8°C | 3.6°C | 23.6°C | -0.8°C | 44 mm | 60% | 2.7 m/s | 5 |
| 1986 | 19.5°C | 13.1°C | 6.6°C | 26.3°C | 1.1°C | 101 mm | 69% | 2.3 m/s | 4.6 |
| 1985 | 16.7°C | 9.6°C | 2.6°C | 24.2°C | -2.9°C | 28 mm | 63% | 2.8 m/s | 5.1 |
| 1984 | 20.2°C | 12.7°C | 5.2°C | 25.7°C | 1.7°C | 9 mm | 54% | 3.3 m/s | 5.1 |
| 1983 | 15.1°C | 10.0°C | 4.9°C | 23.1°C | 1.3°C | 172 mm | 80% | 3.2 m/s | — |
| 1982 | 15.0°C | 9.4°C | 3.7°C | 20.6°C | -0.9°C | 136 mm | 70% | 2.6 m/s | — |
| 1981 | 16.5°C | 10.1°C | 3.7°C | 24.0°C | 1.5°C | 92 mm | 71% | 2.5 m/s | — |
Actual recorded March data for each year, 1981–2025 — sourced from NASA POWER.
The average high in March is around 18.5°C with lows near 4.9°C (mean 11.7°C), based on 45 years of NASA POWER data.
March averages 65 mm of rainfall in Simi Valley, a relatively wet time of year. The wettest on record was 195 mm in 1991.
The hottest March reached 30.5°C in 2013. The coldest dipped to -3.1°C in 2006.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average March temperatures have risen by about 0.6°C. Daytime highs moved from 16.7°C to 17.5°C and overnight lows from 4°C to 4.6°C over the same span.
March is one of the cooler months of the year in Simi Valley and a relatively wet time of year, so plan for around 18.5°C daytime highs and 4.9°C at night.
Not quite — March is the 4th coolest month in Simi Valley, averaging 11.7°C.
For March in Simi Valley, pack warm layers and a jacket for chilly mornings, with typical highs of 18.5°C and lows of 4.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in March averages 65% — moderately humid.
Average wind speed in March is 2.5 m/s. The windiest March on record averaged 3.3 m/s (1984).
The wettest March on record was 1991 with 195 mm. On average, March sees 65 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 Simi Valley behaves each March, 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 March specifically, along with year-by-year records and how the month has changed over the decades.
