Frost dates for W Glacier, 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 18
typical year
Safe to plant
June 4
frost is over in 9 of 10 years
First fall frost
September 20
typical year
Growing season
124 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 20 – May 4 | – |
| Spinach | – | Apr 6 – 27 | Jul 26 – Aug 9 |
| Lettuce | – | Apr 20 – May 11 | Jul 26 – Aug 9 |
| Radishes | – | Apr 20 – Jun 1 | Aug 9 – 23 |
| Onions | – | Apr 20 – May 4 | – |
| Potatoes | – | Apr 27 – May 11 | – |
| Carrots | – | Apr 27 – May 18 | Jun 28 – Jul 12 |
| Beets | – | Apr 20 – May 4 | Jul 12 – 26 |
| Kale | Mar 9 – 23 | Apr 20 – May 4 | Jul 12 – 26 |
| Broccoli | Mar 9 – 23 | May 4 – 18 | Jul 12 – 26 |
| Cabbage | Feb 23 – Mar 9 | Apr 20 – May 4 | Jul 12 – 26 |
| Garlic | – | – | Aug 9 – 30 |
| Warm-season crops | |||
| Tomatoes | Apr 9 – 23 | Jun 4 – 18 | – |
| Peppers | Apr 2 – 16 | Jun 11 – 25 | – |
| Cucumbers | – | Jun 4 – 25 | – |
| Zucchini | – | Jun 4 – Jul 2 | – |
| Pumpkins | – | Jun 4 – 25 | – |
| Green beans | – | Jun 4 – Jul 12 | – |
| Sweet corn | – | Jun 4 – Jul 2 | – |
| Basil | Apr 30 – May 14 | Jun 11 – 18 | – |
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 4 | May 18 | May 6 |
| Fall frost before | September 3 | September 20 | October 4 |
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 1 (May 15 in a late year), and the first one in fall around October 4.
Where these dates come from
NOAA weather station W GLACIER, MT US (USC00248809), 1991–2020 climate normals. It's the nearest station for 2 zip codes, all within 25 miles:
59913, 59928
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.