Climate Insights for Castellar del Vallès

The climate in Castellar del Vallès is temperate. The average annual temperature is 13°C and approximately 904mm of precipitation falls per year. October is the wettest month, receiving around 137mm of rainfall. Castellar del Vallès is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are January, December, February, when temperatures can drop to 1°C. Light snow can occur between January and March.

Temperatures in Castellar del Vallès vary considerably across the year, with a 28°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 29°C and the mean temperature sits around 23°C. January is the coolest month, with minimum temperatures around 1°C and an average of 5°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between October and November, with a 6°C shift in average temperatures.

Castellar del Vallès is a moderately rainy area, receiving approximately 904mm of precipitation annually, which averages out to around 75mm per month. The wettest month is October, averaging 137mm of rainfall. April and May also tend to see above-average precipitation. The driest month is December, with just 27mm. That's 110mm less than October, 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 March, totalling around 12cm annually. February is the snowiest month with approximately 8cm.

Castellar del Vallès is relatively calm, with an average annual wind speed of 2km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is March, averaging 2km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 0km/h between the calmest and windiest months.

It is currently spring in Castellar del Vallès, which began on March 20, 2026. Castellar del Vallès 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 July at around 29°C, while the coldest stretch bottoms out in January near 1°C. Summer is next, beginning on June 21, 2026 — 3 days from now.

The best time to visit Castellar del Vallès is during May, June, July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 79mm per month. By contrast, January can be quite cold with temperatures dropping to 1°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Castellar del Vallès 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.