Rialto (CA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Rialto.
Climate overview of Rialto
Temperatures in Rialto, California, United States of America, vary greatly throughout the year. August is the hottest month at 35°C (95°F), while December is the coldest at 18°C (64°F).
The city tends toward dry conditions, with around 291 mm (11 in) of rainfall per year. It does, however, have a distinct dry season from March to November, with very warm summers and pleasant winters. July is the sunniest month, averaging 12.3 hours of sunshine per day.
Rialto Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Rialto - and find the best time to visit.
Monthly Temperature in Rialto
The climate in Rialto is known for significant temperature differences throughout the year, making the weather dynamic. Typically, average maximum daytime temperatures range from a very warm 35°C (95°F) in August to a pleasant 18°C (64°F) in the coolest month, December.
Nights vary from 18°C (64°F) in August to around 6°C (43°F) during the colder months.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Rialto
Rialto has a relatively dry climate with low precipitation, averaging 291 mm (11 in) of rainfall annually. The climate in Rialto shows significant variation throughout the year. Expect moderate rainfall in December, the wettest month, with an average of 86 mm (3.4 in) of precipitation over 7 rainy days.
In contrast, the driest month June offers drier and sunnier days, with around 0.1 mm (0 in) of rainfall over 0 rainy days. For more details, please visit our Rialto 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 Rialto
For those who appreciate different seasons, Rialto 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 Rialto
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, October and November
- 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 Rialto
What is the best time to visit Rialto?
January, February, March, April, May, October and November typically offer the most optimal weather in Rialto. In contrast, July, August and September tend to have less optimal conditions. Rialto has a distinct dry season from March to November, with very warm summers and pleasant winters.
What temperatures can I expect in Rialto?
Daytime highs range from 18°C (64°F) in December to 35°C (95°F) in August. Nighttime lows range from 6°C (43°F) to 18°C (64°F). Temperatures vary considerably through the year.
How much rain does Rialto get?
Annual rainfall is around 291 mm (11 in). December is the wettest month with 86 mm (3.4 in), while June is the driest with 0.1 mm (0 in).
How sunny is Rialto?
Rialto 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, Rialto enjoys abundant sunshine.
Rialto 3-Day Forecast
Rialto (CA) 3-Day Forecast
Rialto on the map
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