Climate Insights for Walla Walla

The climate in Walla Walla is temperate. The average annual temperature is 12°C and approximately 426mm of precipitation falls per year. December is the wettest month, receiving around 63mm of rainfall. Walla Walla is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are December, January, February, when temperatures can drop to 0°C. Light snow can occur between January and December.

Temperatures in Walla Walla vary considerably across the year, with a 33°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 33°C and the mean temperature sits around 25°C. The coldest month is December, when overnight lows fall to 0°C and the daily average is 2°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between September and October, with a 6°C shift in average temperatures.

Walla Walla is a relatively dry area, receiving approximately 426mm of precipitation annually, which averages out to around 35mm per month. The wettest month is December, averaging 63mm of rainfall. November and February also tend to see above-average precipitation. The driest month is July, with just 2mm. That's 61mm less than December, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic. Light snowfall can occur between January and December, totalling around 40cm annually. February is the snowiest month with approximately 14cm.

Walla Walla is mildly breezy, with an average annual wind speed of 17km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is April, averaging 19km/h, though still comfortable for most outdoor activities. The calmest conditions occur in January, with average winds dropping to 15km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months.

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It is currently spring in Walla Walla, which began on March 20, 2026. Walla Walla is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 33°C, while the coldest stretch bottoms out in December near 0°C. Summer is next, beginning on June 21, 2026 — 51 days from now.

The best time to visit Walla Walla is during May, June, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 19mm per month. By contrast, July can be uncomfortably hot with highs reaching 33°C, while December is the coldest period with lows dropping to 0°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for Walla Walla based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.