Riverside, CA Climate & Monthly Averages

The climate of Riverside

The number that shapes daily life in Riverside is not the seasonal one but the daily one: afternoons run about 14°C warmer than the nights that follow them, every month of the year. August pairs highs of 96°F (35°C) with lows of 67°F (19°C); January pairs 65°F (18°C) with 44°F (7°C).

Climate quick facts

• Hottest month: August - highs near 96°F (35°C)
• Coldest month: January - highs near 65°F (18°C)
• Decade extremes (2015-2024): 116°F (47°C) high · 28°F (-2°C) low
• Wettest month: January (6 rainy days) · Sunniest: July (13.7 h sun/day)
• Climate type: semi-arid
• Annual swing: 14°C between the average warmest and coolest month · day to night: 14°C
• Months averaging 30°C or hotter: 4
• Average humidity: 56%

Temperatures through the year

Sunshine averages 10.8 hours a day over the year - sunnier than 91% of the 3496 cities in our dataset, peaking in July at 13.7 hours. January bottoms out at 65°F (18°C) in daylight, 44°F (7°C) after dark. At its warmest, in August, Riverside runs to 96°F (35°C) in the afternoon and back to 67°F (19°C) by dawn. The wettest month is January (3.4 inches (87 mm) across 6 days) and the driest June.

Rain, sun and snow

Average highs hold at or above 30°C for 4 months of the year, June through September being the unbroken run. Days and nights are about 14°C apart on average - wider than almost anywhere else we cover. Relative humidity averages 56% across the year, drier than all but 10% of the 3496 cities in our dataset. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 116°F (47°C) and the lowest daily minimum 28°F (-2°C).

How Riverside compares

• Rain or snow reaches the ground on 40 days a year - fewer wet days than all but 6% of the 3496 cities we track.
• 59% of the year's precipitation falls in its wettest three months - more seasonal than 91% of the 3496 cities we track.
• Annual precipitation is 14.7 inches (374 mm) - drier than all but 10% of the 3496 cities we track.

Ranked against every city in our dataset, each measured on the same ten-year window.

Best time to visit Riverside

January to May and November is the sweet spot for Riverside - temperatures sit either side of the peak heat rather than in it. Expect 72°F (22°C) in the afternoon and around 5 days of rain in a typical month of it. For the same question asked the other way round, see where else is warm in January.

Pack for Riverside with lightweight, breathable clothing and serious sun protection and a mid-layer for the evenings, which fall away fast after sunset. August nights average 67°F (19°C), so evenings rarely match the afternoons.