Stillwater, OK Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Stillwater, Oklahoma.
Gardening in Stillwater
Oklahoma State University's hometown is one of the premier agricultural universities in America. Stillwater gardeners have access to world-class growing expertise.
Zone 7a with 210 frost-free days. The Cross Timbers region provides slightly more shelter than open prairie. OSU's experimental gardens are among the most sophisticated in the state.
OSU's agricultural programs are the city's identity — Cowboys gardeners have Aggie expertise at their fingertips.
What This Means for Stillwater Gardeners
The average last spring frost in Stillwater is around April 1, and the average first fall frost arrives around October 28. That gives you approximately 210 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 Stillwater 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 Stillwater
Stillwater's 210-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 Oklahoma planting guide for all 40 plants: Oklahoma Planting Calendar. Or enter your zip code for exact planting dates personalized to Stillwater.
More About Zone 7A
Stillwater is in USDA Hardiness Zone 7A, which means average annual extreme minimum temperatures between 0°F to 5°F. View the full Zone 7A planting guide.
See the complete planting calendar for Oklahoma: Oklahoma Planting Calendar.
Other Cities in Oklahoma
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Stillwater 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 Stillwater (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.