UV Index
UV Index
Today's UV index in Simi Valley, United States 
will be up to 11, indicating a extreme level of sun exposure for the average person. Check our tips for today to make sure you're safe in the sun.
Last checked: 2025-07-12
UV index at 11 in Simi Valley means extreme risk: limit outdoor time especially from 10 a.m. to 4 p.m., actively seek shade, wear protective clothing, broad-brimmed hat, apply SPF 30+ sunscreen every 2 hours, and wear UV-blocking sunglasses. Watch for bright surfaces like water and snow increasing UV exposure.
The UV index in Simi Valley is usually moderate to high, especially during summer months when it can reach levels that require sun protection. In winter, the UV index tends to be lower but can still be significant on sunny days.
Simi Valley has warm, dry summers with temperatures often in the 80s and 90s (°F). Winters are mild and cooler, with occasional rain. Spring and fall are pleasant with moderate temperatures and low humidity, making these seasons comfortable.
Compared to nearby Los Angeles and the greater Southern California region, Simi Valley is slightly cooler and less humid. It receives less rainfall than some coastal areas but more than the desert regions to the east. Neighboring cities share similar Mediterranean climates with minor local differences.
See the UV index hour by hour for Simi Valley, along with the temperature and how cloudy it is. If the UV level is higher than moderate, it's best to avoid direct sunlight.