Havre, MT Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Havre, Montana.
Gardening in Havre
Hi-Line Montana sits on the Milk River in the northern Great Plains, close to the Canadian border in conditions that test every gardener.
Zone 4a with 123 frost-free days. Northern Montana's continental climate means extreme cold, summer heat, and persistent wind. The Milk River provides valley fertility.
Havre's self-reliance culture means growing your own food isn't optional — it's traditional. The short season demands creativity.
What This Means for Havre Gardeners
The average last spring frost in Havre is around May 18, and the average first fall frost arrives around September 18. That gives you approximately 123 frost-free days to work with.
123 frost-free days means every warm day counts. Focus on cold-hardy crops that thrive in your moderate temperatures: kale, lettuce, peas, radishes, potatoes, and root vegetables. For warm-season crops, choose only the shortest-season varieties (sub-65-day tomatoes, 55-day beans) and start everything indoors. Season extension — row covers, cold frames, plastic mulch — isn't a luxury here, it's essential infrastructure.
These dates are based on NOAA 30-year Climate Normal data for the Havre 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 Havre
With 123 frost-free days, Havre 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 Montana planting guide for all 40 plants: Montana Planting Calendar. Or enter your zip code for exact planting dates personalized to Havre.
More About Zone 4A
Havre is in USDA Hardiness Zone 4A, which means average annual extreme minimum temperatures between -30°F to -25°F. View the full Zone 4A planting guide.
See the complete planting calendar for Montana: Montana Planting Calendar.
Other Cities in Montana
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Havre 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 Havre (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Start everything possible indoors — your 123-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 18). Choose short-season varieties for warm crops. Enter your zip code for exact dates.