San Ramon (CA) Temperature by Month

San Ramon in California, United States of America sees significant seasonal temperature differences, with daytime highs between 14°C (57°F) in December and 30°C (86°F) in July, averaging 22°C (72°F) annually. Explore the full monthly breakdown below.

Visitors to San Ramon will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 13°C (55°F) in July to 4°C (39°F) in December.

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

Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM. July, the city's warmest month, sees 313 hours of sunshine.

The chart below shows the average temperature throughout the year:

San Ramon's average annual maximum temperature is 22°C (72°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.

Queenstown, New Zealand averages 10°C (50°F) annually, remember seasons are flipped, so its coldest months fall in June and July.

New York City, USA averages 17°C (63°F) a year, with hot humid summers and cold winters that bring regular snowfall.

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

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In San Ramon, December is the coolest month, with average highs of 14°C (57°F) and humidity around 78%, considered high. In July, the warmest month, temperatures average 30°C (86°F) with 75% humidity, conditions that feel high. For a full picture, see our humidity page.

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 San Ramon this rarely lasts long on the ground.

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