Coram, MT frost dates
Last spring frostMay 18median date
First fall frostSep 20median date
Growing season125 daysfrost-free
Hardiness zone5aZone 5a
How Coram compares
- In 8 years out of 10, the last spring frost in Coram falls between May 6 and June 4, a 29-day window. The first fall frost falls between September 3 and October 4.
- The median last frost is 1 day earlier than the Montana median of May 19.
- Its 125-day growing season is longer than 47% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 15 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 180 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 6 |
| 50% (median) | May 18 |
| 10% (safe for tender plants) | June 4 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 3 |
| 50% (median) | September 20 |
| 90% (late) | October 4 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Coram, MT
Coram, MT frost dates — last frost May 18, first frost Sep 20, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 23 to Mar 9Transplant outside: Apr 20 to May 4
Start indoors: Mar 9 to Mar 23Transplant outside: Jun 1 to Jun 15
Start indoors: Mar 9 to Mar 23Transplant outside: Jun 1 to Jun 15
Start indoors: Mar 23 to Apr 6Transplant outside: May 25 to Jun 8
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 27 to May 11Sow outdoors: Apr 20 to May 25Plant for fall: Jul 26 to Aug 23
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 20 to May 4Sow outdoors: Apr 20 to May 4Plant for fall: Jul 12 to Aug 2
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 14 to Jul 5
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 27 to May 11Plant for fall: Jun 14 to Jul 5
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 14 to Jul 5
Start indoors: Apr 6 to Apr 20Transplant outside: Jun 8 to Jun 22Sow outdoors: Jun 8 to Jun 22
Start indoors: Apr 6 to Apr 20Transplant outside: May 25 to Jun 8
Sow outdoors: Apr 6 to Apr 27Plant for fall: Jun 28 to Jul 19
Sow outdoors: Apr 6 to Apr 27Plant for fall: Jul 26 to Aug 16
Sow outdoors: Apr 13 to May 25Plant for fall: Aug 9 to Aug 30
Start indoors: Apr 20 to Apr 27Transplant outside: Jun 1 to Jun 8Sow outdoors: May 25 to Jun 8Plant for fall: Jul 5 to Jul 19
Start indoors: Apr 20 to Apr 27Sow outdoors: May 25 to Jun 8Plant for fall: Jul 12 to Jul 26
Start indoors: Apr 20 to Apr 27Sow outdoors: May 25 to Jun 8
Start indoors: Apr 20 to Apr 27Transplant outside: Jun 1 to Jun 15
Sow outdoors: Apr 27 to May 25Plant for fall: Jun 28 to Jul 12
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 12 to Jul 26
Sow outdoors: Apr 27 to May 18
Sow outdoors: May 4 to Jun 1Plant for fall: Jul 12 to Jul 26
Sow outdoors: May 4 to May 25Plant for fall: Jul 26 to Aug 16
Sow outdoors: May 25 to Jun 15Plant for fall: Jul 5 to Jul 19
Sow outdoors: May 25 to Jun 8
Transplant outside: Jun 1 to Jun 22
Plant for fall: Sep 6 to Oct 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Coram, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 23 – Mar 9 | Apr 20 – May 4 | — | — |
| Peppers | Mar 9 – Mar 23 | Jun 1 – Jun 15 | — | — |
| Eggplant | Mar 9 – Mar 23 | Jun 1 – Jun 15 | — | — |
| Tomatoes | Mar 23 – Apr 6 | May 25 – Jun 8 | — | — |
| Lettuce | Mar 23 – Apr 6 | Apr 27 – May 11 | Apr 20 – May 25 | Jul 26 – Aug 23 |
| Kale | Mar 23 – Apr 6 | Apr 20 – May 4 | Apr 20 – May 4 | Jul 12 – Aug 2 |
| Broccoli | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 14 – Jul 5 |
| Cabbage | Mar 23 – Apr 6 | Apr 27 – May 11 | — | Jun 14 – Jul 5 |
| Cauliflower | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 14 – Jul 5 |
| Okra | Apr 6 – Apr 20 | Jun 8 – Jun 22 | Jun 8 – Jun 22 | — |
| Basil | Apr 6 – Apr 20 | May 25 – Jun 8 | — | — |
| Peas | — | — | Apr 6 – Apr 27 | Jun 28 – Jul 19 |
| Spinach | — | — | Apr 6 – Apr 27 | Jul 26 – Aug 16 |
| Radishes | — | — | Apr 13 – May 25 | Aug 9 – Aug 30 |
| Cucumbers | Apr 20 – Apr 27 | Jun 1 – Jun 8 | May 25 – Jun 8 | Jul 5 – Jul 19 |
| Zucchini & Summer Squash | Apr 20 – Apr 27 | — | May 25 – Jun 8 | Jul 12 – Jul 26 |
| Winter Squash & Pumpkins | Apr 20 – Apr 27 | — | May 25 – Jun 8 | — |
| Melons & Watermelon | Apr 20 – Apr 27 | Jun 1 – Jun 15 | — | — |
| Carrots | — | — | Apr 27 – May 25 | Jun 28 – Jul 12 |
| Beets | — | — | Apr 27 – May 25 | Jul 12 – Jul 26 |
| Potatoes | — | — | Apr 27 – May 18 | — |
| Swiss Chard | — | — | May 4 – Jun 1 | Jul 12 – Jul 26 |
| Cilantro | — | — | May 4 – May 25 | Jul 26 – Aug 16 |
| Green Beans | — | — | May 25 – Jun 15 | Jul 5 – Jul 19 |
| Sweet Corn | — | — | May 25 – Jun 8 | — |
| Sweet Potatoes | — | Jun 1 – Jun 22 | — | — |
| Garlic | — | — | — | Sep 6 – Oct 11 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the W Glacier, MT weather station, 9 km away (elevation 3,150 ft (960 m)).
Frost dates near Coram
- Martin City May 9 · Oct 1
- Hungry Horse May 9 · Oct 1
- West Glacier May 18 · Sep 20
- Columbia Falls May 31 · Sep 10
- Lake Mc Donald May 9 · Oct 1
- Whitefish May 16 · Sep 25
- Kalispell May 31 · Sep 10
- Essex May 9 · Oct 1
- Olney frost any month
- Bigfork May 12 · Sep 25
Frequently asked questions
When is the last frost in Coram, MT?
The median last spring frost in Coram, MT is May 18. There is still about a 10% chance of frost after June 4, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Coram, MT?
The median first fall frost is September 20, with about a 10% chance of frost before September 3.
How long is the growing season in Coram, MT?
About 125 days between the median last spring frost and first fall frost.
What planting zone is Coram, MT?
Coram, MT is in USDA hardiness zone 5a.