Fullerton (CA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Fullerton.
Climate overview of Fullerton
The climate in Fullerton, California, United States of America, sees a moderate range of temperatures across the year, from 31°C (88°F) in September down to 20°C (68°F) in December.
The area sees almost no rainfall, totalling just 242 mm (9.5 in) per year. July is the sunniest month, averaging 12.3 hours of sunshine per day.
Fullerton Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Fullerton - and find the best time to visit.
Monthly Temperature in Fullerton
The weather in Fullerton changes moderately throughout the year, offering enough variation to appreciate each season. Typically, average maximum daytime temperatures range from a very warm 31°C (88°F) in September to a pleasant 20°C (68°F) in the coolest month, December.
Nights vary from 18°C (64°F) in September to around 8°C (46°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Fullerton
Fullerton sits in an arid zone with minimal moisture, averaging 242 mm (9.5 in) of rainfall per year. The climate in Fullerton shows significant variation throughout the year. Expect moderate rainfall in December, the wettest month, with an average of 67 mm (2.6 in) of precipitation over 8 rainy days.
In contrast, the driest month August offers drier and sunnier days, with around 0.3 mm (0.01 in) of rainfall over 0 rainy days. For more details, please visit our Fullerton Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Fullerton
For those who appreciate different seasons, Fullerton serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 12.3 hours of sunshine daily, and embrace the darker days in January, offering only 6.6 hours of daily sunlight.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Best Time to Visit Fullerton
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: January, February, March, April, May, June, October, November and December
- Warmest weather: July, August and September
- Most sunshine: July and August
- Fewer rainy days: May, June, July, August and September
- Seasonal pattern: A distinct dry season from March to November, with very warm summers and pleasant winters
Frequently asked questions about the climate in Fullerton
What is the best time to visit Fullerton?
January, February, March, April, May, June, October, November and December typically offer the most optimal weather in Fullerton. In contrast, July, August and September tend to have less optimal conditions. Fullerton has a distinct dry season from March to November, with very warm summers and pleasant winters.
What temperatures can I expect in Fullerton?
Daytime highs range from 20°C (68°F) in December to 31°C (88°F) in September. Nighttime lows range from 8°C (46°F) to 18°C (64°F).
How much rain does Fullerton get?
Annual rainfall is around 242 mm (9.5 in). December is the wettest month with 67 mm (2.6 in), while August is the driest with 0.3 mm (0.01 in).
How sunny is Fullerton?
Fullerton receives around 3,279 hours of sunshine per year. July is the sunniest month with 369 hours, while January is the cloudiest with just 198 hours. Overall, Fullerton enjoys abundant sunshine.
Fullerton 3-Day Forecast
Fullerton on the map
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Popular this month
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