Climate Insights for Castaic

The climate in Castaic is temperate. The average annual temperature is 17°C and approximately 390mm of precipitation falls per year. Gennaio is the wettest month, receiving around 83mm of rainfall. Castaic is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: Agosto, Luglio, Settembre. The coldest months are Dicembre, Gennaio, Febbraio, when temperatures can drop to 5°C. Light snow can occur between January and December.

Temperatures in Castaic vary considerably across the year, with a 26°C difference between the coldest and warmest months. The warmest month is Agosto, when average highs reach 31°C and the mean temperature sits around 25°C. Dicembre is the coolest month, with minimum temperatures around 5°C and an average of 10°C. On average, daily temperatures fluctuate by about 12°C between overnight lows and afternoon highs. The sharpest temperature change occurs between October and November, with a 5°C shift in average temperatures.

Castaic is a quite dry location, receiving approximately 390mm of precipitation annually, which averages out to around 32mm per month. The wettest month is January, averaging 83mm of rainfall. February and March also tend to see above-average precipitation. The driest month is July, with just 3mm. That's 80mm less than January, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Light snowfall can occur between January and December, totalling around 15cm annually. February is the snowiest month with approximately 4cm.

Castaic is mildly breezy, with an average annual wind speed of 12km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in September, with average winds dropping to 11km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.

It is currently spring in Castaic, which began on March 20, 2026. Castaic is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in Agosto at around 31°C, while the coldest stretch bottoms out in Dicembre near 5°C. Summer is next, beginning on June 21, 2026 — 92 days from now.

The best time to visit Castaic is during Aprile, Maggio, Giugno, Luglio, Agosto, Settembre and Ottobre, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 11mm per month. By contrast, Dicembre can be quite cold with temperatures dropping to 5°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for Castaic based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.