April is one of the cooler months of the year in Simi Valley, with average highs near 22°C and lows around 6.7°C (mean 14.4°C). It is one of the drier months, averaging 21 mm of rainfall and 58% relative humidity across the period.
April is one of the cooler months of the year in Simi Valley. Across 45 years of records, the warmest April in Simi Valley was 1989 — when the month averaged 17.6°C — while the coldest was 1983 at 10.3°C. Typical April days reach 22°C with nights near 6.7°C. The long-term trend is warming, about 0.3°C per decade.
April is one of the drier months in Simi Valley, averaging 21 mm of rainfall. The wettest April on record was 2020 with 86 mm, while the driest was 1997 at 0 mm.
Relative humidity in Simi Valley during April averages 58%. The most humid April was 2006 at 73%, and the least humid was 2021 at 44%.
April receives about 6.6 kWh/m²/day of solar energy in Simi Valley. The sunniest April was 2008 at 7.4 kWh/m²/day, and the cloudiest was 2006 at 5.7.
Average wind speed in Simi Valley during April is 2.5 m/s. The windiest Aprils were 1984 and 1996 at 3.4 m/s, while the calmest were 2004 and 2025 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.3°C | 14.0°C | 13.7°C | 15.0°C | 15.0°C | +0.7°C |
| Avg High | 22.0°C | 21.4°C | 21.3°C | 22.6°C | 22.8°C | +0.8°C |
| Avg Low | 6.7°C | 6.5°C | 6.0°C | 7.4°C | 7.3°C | +0.6°C |
| Avg Rain | 28 mm | 15 mm | 26 mm | 14 mm | 21 mm | -7 mm |
April temperatures in Simi Valley have risen by about 1.7°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -1.6°C (1999) to a record high of 34.6°C (2021).
Rainfall in April is one of the drier months, averaging 21 mm, with a wettest year of 86 mm.
A good time to visit Simi Valley
April is a good time to visit Simi Valley, with days averaging 22°C and nights around 6.7°C (mean 14.4°C, cooler than Simi Valley's yearly average) and low rainfall. June and September are marginally more temperate, but April still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 22.5°C | 15.1°C | 7.7°C | 30.7°C | 2.0°C | 8 mm | 61% | 2 m/s | 6.3 |
| 2024 | 20.8°C | 13.6°C | 6.3°C | 28.3°C | 0.5°C | 24 mm | 68% | 2.3 m/s | 6.5 |
| 2023 | 22.1°C | 14.5°C | 6.8°C | 29.0°C | -0.2°C | 1 mm | 64% | 2.2 m/s | 6.9 |
| 2022 | 23.9°C | 15.5°C | 7.2°C | 32.8°C | 1.8°C | 6 mm | 53% | 2.6 m/s | 7.1 |
| 2021 | 25.8°C | 16.8°C | 7.9°C | 34.6°C | 3.4°C | 2 mm | 44% | 2.3 m/s | 7 |
| 2020 🌧️ | 21.4°C | 14.6°C | 7.9°C | 31.5°C | 1.8°C | 86 mm | 68% | 2.5 m/s | 6 |
| 2019 | 22.3°C | 15.4°C | 8.6°C | 29.1°C | 4.8°C | 3 mm | 65% | 2.4 m/s | 6.4 |
| 2018 | 23.7°C | 15.7°C | 7.7°C | 29.9°C | 1.7°C | 2 mm | 54% | 2.4 m/s | 6.9 |
| 2017 | 22.4°C | 15.1°C | 7.8°C | 29.3°C | 2.7°C | 5 mm | 60% | 3 m/s | 6.9 |
| 2016 | 23.1°C | 15.9°C | 8.6°C | 29.7°C | 3.2°C | 14 mm | 55% | 2.5 m/s | 6.7 |
| 2015 | 23.2°C | 15.4°C | 7.7°C | 30.4°C | 1.3°C | 7 mm | 48% | 2.3 m/s | 6.8 |
| 2014 | 23.8°C | 15.8°C | 7.8°C | 29.4°C | 1.4°C | 8 mm | 49% | 2.5 m/s | 7 |
| 2013 | 24.9°C | 16.3°C | 7.7°C | 33.5°C | 0.9°C | 2 mm | 48% | 2.5 m/s | 6.9 |
| 2012 | 23.0°C | 14.7°C | 6.5°C | 32.6°C | 0.2°C | 47 mm | 56% | 2.7 m/s | 6.6 |
| 2011 | 20.7°C | 13.6°C | 6.6°C | 29.1°C | -1.1°C | 2 mm | 65% | 2.7 m/s | 6.7 |
| 2010 | 18.8°C | 11.6°C | 4.5°C | 26.6°C | 1.3°C | 44 mm | 67% | 2.5 m/s | 6.6 |
| 2009 | 21.5°C | 13.3°C | 5.2°C | 32.9°C | 0.3°C | 5 mm | 55% | 2.4 m/s | 6.9 |
| 2008 | 22.5°C | 14.0°C | 5.5°C | 30.3°C | 0.5°C | 2 mm | 51% | 2.7 m/s | 7.4 |
| 2007 | 23.2°C | 15.0°C | 6.9°C | 33.0°C | 1.7°C | 16 mm | 52% | 2.5 m/s | 6.5 |
| 2006 | 18.2°C | 12.1°C | 5.9°C | 28.2°C | 1.5°C | 75 mm | 73% | 2.1 m/s | 5.7 |
| 2005 | 20.1°C | 12.7°C | 5.4°C | 26.0°C | 2.6°C | 21 mm | 64% | 2.5 m/s | 6.9 |
| 2004 | 24.0°C | 15.8°C | 7.6°C | 34.0°C | 2.5°C | 4 mm | 53% | 2 m/s | 6.9 |
| 2003 | 17.8°C | 11.2°C | 4.5°C | 25.5°C | 0.3°C | 43 mm | 67% | 2.4 m/s | 6.2 |
| 2002 | 22.7°C | 14.9°C | 7.0°C | 33.5°C | 2.1°C | 4 mm | 54% | 2.3 m/s | 6.5 |
| 2001 | 19.8°C | 12.3°C | 4.9°C | 29.3°C | -0.4°C | 33 mm | 64% | 2.1 m/s | 6.4 |
| 2000 | 23.1°C | 15.3°C | 7.5°C | 30.6°C | 2.8°C | 58 mm | 60% | 2.6 m/s | 6.6 |
| 1999 | 18.7°C | 11.6°C | 4.6°C | 31.2°C | -1.6°C | 54 mm | 60% | 2.8 m/s | 6.1 |
| 1998 | 18.0°C | 11.3°C | 4.6°C | 28.1°C | -0.4°C | 33 mm | 70% | 2.3 m/s | 6.5 |
| 1997 | 22.2°C | 14.6°C | 7.0°C | 29.8°C | 0.9°C | 0 mm | 54% | 3.3 m/s | 6.7 |
| 1996 | 23.5°C | 15.8°C | 8.0°C | 33.5°C | 2.8°C | 14 mm | 54% | 3.4 m/s | 7.1 |
| 1995 | 19.8°C | 12.8°C | 5.8°C | 26.9°C | 1.4°C | 22 mm | 67% | 2.7 m/s | 6.4 |
| 1994 | 22.4°C | 14.6°C | 6.8°C | 30.4°C | 1.7°C | 16 mm | 57% | 2.2 m/s | 6.4 |
| 1993 | 21.9°C | 14.4°C | 6.9°C | 29.5°C | 3.9°C | 1 mm | 64% | 3.2 m/s | 7.1 |
| 1992 | 23.9°C | 16.0°C | 8.1°C | 30.2°C | 3.5°C | 1 mm | 62% | 2.3 m/s | 6.8 |
| 1991 | 20.3°C | 12.7°C | 5.0°C | 28.4°C | 0.5°C | 1 mm | 63% | 2.8 m/s | 6.8 |
| 1990 | 23.5°C | 15.8°C | 8.0°C | 30.9°C | 3.9°C | 9 mm | 56% | 2.3 m/s | 6.1 |
| 1989 🔥 | 26.0°C | 17.6°C | 9.2°C | 34.3°C | 2.7°C | 5 mm | 50% | 2.4 m/s | 6.7 |
| 1988 | 21.4°C | 14.1°C | 6.8°C | 30.7°C | 3.2°C | 69 mm | 57% | 2.5 m/s | 5.8 |
| 1987 | 25.6°C | 17.1°C | 8.7°C | 31.0°C | 2.8°C | 4 mm | 45% | 2.5 m/s | 6.7 |
| 1986 | 20.4°C | 13.1°C | 5.9°C | 27.8°C | 2.4°C | 23 mm | 63% | 2.6 m/s | 6.3 |
| 1985 | 24.6°C | 16.2°C | 7.8°C | 31.2°C | 2.2°C | 2 mm | 48% | 2.7 m/s | 7 |
| 1984 | 21.4°C | 13.4°C | 5.4°C | 30.4°C | -0.2°C | 8 mm | 48% | 3.4 m/s | 6.3 |
| 1983 ❄️ | 16.2°C | 10.3°C | 4.4°C | 22.0°C | -0.7°C | 84 mm | 71% | 2.8 m/s | — |
| 1982 | 20.0°C | 12.8°C | 5.5°C | 25.9°C | -0.3°C | 45 mm | 64% | 2.8 m/s | — |
| 1981 | 22.8°C | 14.5°C | 6.2°C | 32.4°C | 1.2°C | 15 mm | 56% | 2.3 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 22°C with lows near 6.7°C (mean 14.4°C), based on 45 years of NASA POWER data.
April averages 21 mm of rainfall in Simi Valley, one of the drier months. The wettest on record was 86 mm in 2020.
The hottest April reached 34.6°C in 2021. The coldest dipped to -1.6°C in 1999.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 1.7°C. Daytime highs moved from 21°C to 23°C and overnight lows from 5.9°C to 7.2°C over the same span.
April is one of the cooler months of the year in Simi Valley and one of the drier months, so plan for around 22°C daytime highs and 6.7°C at night.
Not quite — April is the 6th coolest month in Simi Valley, averaging 14.4°C.
For April in Simi Valley, pack warm layers and a jacket for chilly mornings, with typical highs of 22°C and lows of 6.7°C.
Relative humidity in April averages 58% — moderately humid.
Average wind speed in April is 2.5 m/s. The windiest April on record averaged 3.4 m/s (1984).
The wettest April on record was 2020 with 86 mm. On average, April sees 21 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 April, 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 April specifically, along with year-by-year records and how the month has changed over the decades.
