Riverside (CA) Temperature by Month

The average annual maximum temperature in Riverside, California, United States of America is 27°C (81°F), with daytime highs ranging from 19°C (66°F) in December to 35°C (95°F) in August. This page covers monthly averages, day-night differences, and how Riverside compares to cities worldwide.

Visitors to Riverside can expect significant temperature changes throughout the year. Nighttime temperatures also vary widely, ranging from 18°C (64°F) in August to 6°C (43°F) in December.

The chart below illustrates the average maximum day and minimum night temperatures in Riverside by month:

The coolest part of the day is typically between 4 AM and 6 AM, while 3 PM is usually the warmest, when solar heating is at its peak. August, the city's warmest month, averages 351 hours of sunshine.

The chart below shows the average temperature throughout the year:

Riverside's average annual maximum temperature is 27°C (81°F). To put that in context, here's how it compares to a few well-known destinations:

Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.

Zermatt, Switzerland averages just 4°C (39°F) annually due to its altitude, with very cold winters and cool summers even at its warmest.

Osaka, Japan averages 22°C (72°F) annually, with hot humid summers, mild winters, and pleasant spring and autumn seasons.

Melbourne, Australia averages 20°C (68°F) annually, known for unpredictable weather, with four seasons sometimes happening in one day.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Seasonal temperature shifts influence more than just how warm it feels, they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.

Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Riverside this rarely lasts long on the ground.

For more on Riverside's weather, including monthly rainfall, sunshine hours, and humidity, visit our Riverside climate page.