🌷 Your Ultimate Garden Calendar!

🍂 First Frost Dates for Heart Butte, Montana 59448

A 36°F frost is always a risk here. (See detailed probabilities below.)

A 32°F light freeze is always a risk here. (See detailed probabilities below.)

(See also 🌷 Last Spring Frost Dates.)

First frost date probabilities for Heart Butte, MT are based on historical climate data.

Always check your local forecast for the most up-to-date frost warnings.

Book Recommendations (ads!)

📚 Growing Under Cover: Techniques for a More Productive, Weather-Resistant, Pest-Free Vegetable Garden

📚 Greenhouse Gardening for Beginners: Step By Step Guide To Build A Year-Round Greenhouse And Grow Herbs, Organic Fruits And Vegetables, Plants, Flowers Plans & Ideas for Extending the Growing Season

📚 How to Garden Indoors & Grow Your Own Food Year Round: Ultimate Guide to Vertical, Container, and Hydroponic Gardening (Creative Homeowner) Vegetables, Herbs, DIY Projects, Composting, Lights, & More

📚 The Year-Round Vegetable Gardener: How to Grow Your Own Food 365 Days a Year, No Matter Where You Live

What is a First Frost Date?

The first fall frost signals the end of your local growing season. This date serves as an important deadline for gardeners and farmers. You'll need to complete harvesting before this point. Annuals and other tender plants will die back when frost hits, and perennial plants will enter their dormant phase for winter. Meanwhile, it's time to enjoy a cup of hot cocoa and a cozy sweater—and start planning your spring garden!

How to use the First Frost Date?

Watch your local weather forecasts in early fall to predict the first frost date. Harvest tender crops and protect vulnerable plants before frost arrives. For late-summer plantings, count backward from your area's average first frost date. This ensures your crops have enough time to mature. Keep track of when frost actually occurs in your garden each year. This helps you identify protected spots where the growing season might last longer.

First Frost Date Probabilities

Probability of frost (36°F) on or before...
10% chancealways
20% chancealways
30% chancealways
40% chancealways
50% chancealways
60% chancealways
70% chancealways
80% chancealways
90% chancealways
Probability of light freeze (32°F) on or before...
10% chancealways
20% chancealways
30% chancealways
40% chancealways
50% chancealways
60% chancealways
70% chancealways
80% chancealways
90% chancealways
Probability of moderate freeze (28°F) on or before...
10% chanceSep 3
20% chanceSep 10
30% chanceSep 14
40% chanceSep 18
50% chanceSep 21
60% chanceSep 24
70% chanceSep 27
80% chanceOct 1
90% chanceOct 5
Probability of moderate hard freeze (24°F) on or before...
10% chanceSep 17
20% chanceSep 23
30% chanceSep 27
40% chanceOct 1
50% chanceOct 3
60% chanceOct 5
70% chanceOct 8
80% chanceOct 13
90% chanceOct 19
Probability of hard freeze (20°F) on or before...
10% chanceSep 28
20% chanceOct 2
30% chanceOct 5
40% chanceOct 9
50% chanceOct 13
60% chanceOct 17
70% chanceOct 21
80% chanceOct 25
90% chanceNov 1
Probability of severe hard freeze (16°F) on or before...
10% chanceOct 4
20% chanceOct 10
30% chanceOct 16
40% chanceOct 20
50% chanceOct 24
60% chanceOct 28
70% chanceNov 1
80% chanceNov 5
90% chanceNov 13

Agricultural climatic data from weather station: EAST GLACIER (USC00242629)

Back to Weather Calendar