Climate averages 1991–2020
Simi Valley weather
in January.
A mild, wet month: the 11th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a mild month in Simi Valley: daytime highs average 17.7°C and nights cool to about 6.0°C. By daytime temperature it is the 11th warmest of the 12 months.
Expect about 91 mm of rain on roughly 6 days, which makes January a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 10 h 09 min on an average January day.
The nearest other city in this atlas is Thousand Oaks (12 km away). In January its highs average 17.6°C, about as warm as Simi Valley, with 91 mm of rain.
Among the 498 cities listed in the United States, Simi Valley ranks joint 79th of 498 for the warmest January highs and joint 358th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Simi Valley is 8.2°C warmer than that mean.
From January to February, average highs rise by 0.2°C to 17.8°C, and monthly rainfall rises from 91 mm to 98 mm.
The annual picture
January in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Simi Valley climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January, selected | 17.7°C6.0°C | 6.0°C | 91 | 5.6 | 10.110 h |
| February | 17.8°C6.4°C | 6.4°C | 98 | 6.4 | 10.911 h |
| March | 19.5°C7.9°C | 7.9°C | 66 | 5.6 | 11.912 h |
| April | 21.7°C9.7°C | 9.7°C | 22 | 2.9 | 13.013 h |
| May | 23.9°C12.7°C | 12.7°C | 12 | 1.8 | 13.914 h |
| June | 26.8°C15.6°C | 15.6°C | 2.0 | 0.5 | 14.414 h |
| July | 29.6°C18.7°C | 18.7°C | 3.1 | 0.5 | 14.214 h |
| August | 30.7°C19.3°C | 19.3°C | 0.3 | 0.1 | 13.413 h |
| September | 29.5°C17.6°C | 17.6°C | 3.9 | 0.6 | 12.412 h |
| October | 25.8°C13.7°C | 13.7°C | 20 | 2.1 | 11.411 h |
| November | 21.5°C9.2°C | 9.2°C | 21 | 2.6 | 10.410 h |
| December | 17.4°C5.9°C | 5.9°C | 58 | 4.8 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
January in nearby cities
- Thousand Oaks in JanuaryUnited States · 12 kmHigh 17.6°C · Low 6.6°C · 91 mm rain
- Valencia, United States in JanuaryUnited States · 25 kmHigh 17.4°C · Low 5.1°C · 70 mm rain
- Santa Clarita in JanuaryUnited States · 26 kmHigh 16.9°C · Low 5.0°C · 70 mm rain
- Oxnard in JanuaryUnited States · 37 kmHigh 16.6°C · Low 8.9°C · 93 mm rain
- Burbank in JanuaryUnited States · 45 kmHigh 18.7°C · Low 6.6°C · 86 mm rain
- Ventura in JanuaryUnited States · 47 kmHigh 17.1°C · Low 7.4°C · 93 mm rain
- Glendale (California), United States in JanuaryUnited States · 50 kmHigh 18.4°C · Low 6.5°C · 86 mm rain
- Inglewood in JanuaryUnited States · 52 kmHigh 18.6°C · Low 7.0°C · 80 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Simi Valley) is explained once on the Simi Valley year overview and on the Sources, method and limits page.
Thousand Oaks lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.