Frost dates for Bozeman Exp Farm, MT
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
May 23
typical year
Safe to plant
June 12
frost is over in 9 of 10 years
First fall frost
September 23
typical year
Growing season
123 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Apr 25 – May 9 | – |
| Spinach | – | Apr 11 – May 2 | Jul 29 – Aug 12 |
| Lettuce | – | Apr 25 – May 16 | Jul 29 – Aug 12 |
| Radishes | – | Apr 25 – Jun 6 | Aug 12 – 26 |
| Onions | – | Apr 25 – May 9 | – |
| Potatoes | – | May 2 – 16 | – |
| Carrots | – | May 2 – 23 | Jul 1 – 15 |
| Beets | – | Apr 25 – May 9 | Jul 15 – 29 |
| Kale | Mar 14 – 28 | Apr 25 – May 9 | Jul 15 – 29 |
| Broccoli | Mar 14 – 28 | May 9 – 23 | Jul 15 – 29 |
| Cabbage | Feb 28 – Mar 14 | Apr 25 – May 9 | Jul 15 – 29 |
| Garlic | – | – | Aug 12 – Sep 2 |
| Warm-season crops | |||
| Tomatoes | Apr 17 – May 1 | Jun 12 – 26 | – |
| Peppers | Apr 10 – 24 | Jun 19 – Jul 3 | – |
| Cucumbers | – | Jun 12 – Jul 3 | – |
| Zucchini | – | Jun 12 – Jul 10 | – |
| Pumpkins | – | Jun 12 – Jul 3 | – |
| Green beans | – | Jun 12 – Jul 15 | – |
| Sweet corn | – | Jun 12 – Jul 10 | – |
| Basil | May 8 – 22 | Jun 19 – 26 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | June 12 | May 23 | May 5 |
| Fall frost before | September 4 | September 23 | October 6 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around May 2 (May 18 in a late year), and the first one in fall around October 3.
Where these dates come from
NOAA weather station BOZEMAN 6 W EXP FARM, MT US (USC00241047), 1991–2020 climate normals. It's the nearest station for 1 zip code, all within 2 miles:
59718
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.