San Jose (CA) Temperature by Month

San Jose in California, United States of America sees significant seasonal temperature differences, with daytime highs between 15°C (59°F) in December and 27°C (81°F) in July, averaging 22°C (72°F) annually. Explore the full monthly breakdown below.

The climate in San Jose is known for significant temperature differences throughout the year. At night, this contrast is just as clear, with lows ranging from 15°C (59°F) in July to 5°C (41°F) in December.

The chart below illustrates the average maximum day and minimum night temperatures in San Jose 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. July, the city's warmest month, averages 313 hours of sunshine.

The chart below shows the average temperature throughout the year:

San Jose'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.

On the cooler end, Oslo, Norway averages just 10°C (50°F) annually, with pleasant summers but long, cold winters.

Boston, USA averages 16°C (61°F) annually, with four distinct seasons and cold winters that rival northern Europe.

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 Jose, December is the coolest month, with average highs of 15°C (59°F) and humidity around 78%, considered high. In July, the warmest month, temperatures average 27°C (81°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.

Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round, large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.

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