Green Bay, WI Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Green Bay, Wisconsin.
Gardening in Green Bay
Titletown's gardening season is as compressed and intense as a Packers fourth quarter — short, dramatic, and requiring everything you've got.
Zone 5a on the shore of Green Bay means lake-moderated falls but late, cold springs. Your 149-day growing season demands short-season varieties. The sandy glacial soils are naturally well-drained — an advantage for root crops.
Packers fans own the team; Green Bay gardeners own their food supply. The community-owned team spirit extends to community gardens and the downtown farmers market. Belgian and German heritage neighborhoods grow food traditions that go back generations.
What This Means for Green Bay Gardeners
The average last spring frost in Green Bay is around May 5, and the average first fall frost arrives around October 1. That gives you approximately 149 frost-free days to work with.
At 149 days, you're working with a compressed but productive window. Choose varieties by their days-to-maturity number — anything under 75 days is safe, 75-90 requires indoor starting, and 90+ is a calculated risk. The tradeoff: your cool, moderate summers are excellent for crops that heat-zone gardeners struggle with. Your lettuce doesn't bolt in June. Your peas produce for weeks longer. Cool-season crops are your superpower.
These dates are based on NOAA 30-year Climate Normal data for the Green Bay 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 Green Bay
With 149 frost-free days, Green Bay gardeners need to plan strategically — start warm-season crops indoors and choose short-season varieties. Cool-season crops are your strength, thriving in the moderate temperatures that define your growing window. Recommended starting points: kale, lettuce, peas, carrots, potatoes, radishes, garlic, and short-season tomatoes.
See the full Wisconsin planting guide for all 40 plants: Wisconsin Planting Calendar. Or enter your zip code for exact planting dates personalized to Green Bay.
More About Zone 5A
Green Bay is in USDA Hardiness Zone 5A, which means average annual extreme minimum temperatures between -20°F to -15°F. View the full Zone 5A planting guide.
See the complete planting calendar for Wisconsin: Wisconsin Planting Calendar.
Other Cities in Wisconsin
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Green Bay 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 Green Bay (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Start everything possible indoors — your 149-day season doesn't leave room for a slow start. Direct sow only the fastest, hardiest crops (radishes, lettuce, peas) 3-4 weeks before last frost (May 5). Choose short-season varieties for warm crops. Enter your zip code for exact dates.