Clayton (MO) Temperature by Month

The average annual maximum temperature in Clayton, Missouri, United States of America is 19°C (66°F), with daytime highs ranging from 5°C (41°F) in January to 32°C (90°F) in July. This page covers monthly averages, day-night differences, and how Clayton compares to cities worldwide.

Depending on the time of the year, temperatures range from very warm to cold in Clayton. At night, minimum temperatures range from 21°C (70°F) in July to -5°C (23°F) in January.

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

Daily lows are most common between 4 AM and 6 AM. By 3 PM temperatures reach their daily high, driven by peak solar heating. July, the warmest month of the year, receives 311 hours of sunshine.

The chart below shows the average temperature throughout the year:

Clayton's average annual maximum temperature is 19°C (66°F). To put that in context, here's how it compares to a few well-known destinations:

Seville, Spain averages 23°C (73°F) a year, one of the warmer cities in Western Europe, with long hot summers.

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

Shanghai, China averages 21°C (70°F) a year, with warm summers, mild winters, and a noticeable spring and autumn.

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 the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.

In Clayton, January is the coolest month, with average highs of 5°C (41°F) and humidity around 72%, considered high. In July, the warmest month, temperatures average 32°C (90°F) with 68% 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 Clayton this rarely lasts long on the ground.

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