Walla Walla, WA Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Walla Walla, Washington.
Gardening in Walla Walla
The wine country of eastern Washington also grows the state's most famous onion. The valley's fertile loess soils produce food of exceptional quality.
Zone 7b with 207 frost-free days. The Blue Mountains to the east provide shelter. The valley's loess (wind-deposited silt) soil is deep and fertile. Warm summers, cold winters, low humidity.
Walla Walla Sweet Onions are protected by federal trademark. The same conditions that grow America's most famous onion grow exceptional gardens. The wine industry's sophistication extends to food culture.
What This Means for Walla Walla Gardeners
The average last spring frost in Walla Walla is around April 1, and the average first fall frost arrives around October 25. That gives you approximately 207 frost-free days to work with.
That's a generous season. You have time for full-size tomatoes, long-season peppers, and even watermelons without the anxiety of racing the frost. Start warm-season seeds indoors 6-8 weeks before your last frost to hit the ground running. Fall planting is your second opportunity — garlic, kale, lettuce, and broccoli all go in 8-10 weeks before your first frost for harvest into late autumn.
These dates are based on NOAA 30-year Climate Normal data for the Walla Walla area. Your actual frost dates could shift 2-3 weeks in either direction in any given year. Learn more about our data sources.
What to Grow in Walla Walla
Walla Walla's 207-day growing season is generous — long enough for two full growing windows (spring and fall) with warm-season crops between them. You can grow the full range of vegetables, herbs, and flowers with proper timing. Focus on heat-tolerant varieties for midsummer and cool-season crops for extended fall harvests. Recommended starting points: tomatoes, peppers, beans, cucumbers, squash, garlic, kale, and sunflowers.
See the full Washington planting guide for all 40 plants: Washington Planting Calendar. Or enter your zip code for exact planting dates personalized to Walla Walla.
More About Zone 7B
Walla Walla is in USDA Hardiness Zone 7B, which means average annual extreme minimum temperatures between 5°F to 10°F. View the full Zone 7B planting guide.
See the complete planting calendar for Washington: Washington Planting Calendar.
Other Cities in Washington
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Walla Walla area. They represent historical averages, not predictions. In any given year, the actual last frost could be 2-3 weeks earlier or later. Microclimates within Walla Walla (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Cool-season crops go in 3-4 weeks before your last frost (April 1). Warm-season crops wait until 2 weeks after. You have time for a fall round too — plant cool-season crops again in late summer for harvest into autumn. Enter your zip code for exact dates.