Westminster (CA) Temperature by Month

Westminster in California, United States of America sees moderate seasonal temperature shifts, with daytime highs between 19°C (66°F) in December and 28°C (82°F) in September, averaging 24°C (75°F) annually. Explore the full monthly breakdown below.

The climate in Westminster experiences moderate temperature changes, with mild shifts between seasons. At night, temperatures range from 18°C (64°F) in September to 8°C (46°F) in December.

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

The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM. September, the city's warmest month, gets 290 hours of sunshine.

The chart below shows the average temperature throughout the year:

Westminster's average annual maximum temperature is 24°C (75°F). To put that in context, here's how it compares to a few well-known destinations:

Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.

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

Beijing, China averages 20°C (68°F) annually, but with big seasonal swings, very cold winters and hot summers.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

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 Westminster's weather, including monthly rainfall, sunshine hours, and humidity, visit our Westminster climate page.