Ashland, MT frost dates
Last spring frostMay 18median date
First fall frostSep 22median date
Growing season127 daysfrost-free
Hardiness zone4bZone 4b
How Ashland compares
- In 8 years out of 10, the last spring frost in Ashland falls between May 6 and May 30, a 24-day window. The first fall frost falls between September 8 and October 5.
- The median last frost is 1 day earlier than the Montana median of May 19.
- Its 127-day growing season is longer than 54% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 10 days later than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 178 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) | May 30 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 8 |
| 50% (median) | September 22 |
| 90% (late) | October 5 |
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 Ashland, MT
Ashland, MT frost dates — last frost May 18, first frost Sep 22, zone 4b. 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 28 to Aug 25
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 20 to May 4Sow outdoors: Apr 20 to May 4Plant for fall: Jul 14 to Aug 4
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 16 to Jul 7
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 27 to May 11Plant for fall: Jun 16 to Jul 7
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 16 to Jul 7
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 30 to Jul 21
Sow outdoors: Apr 6 to Apr 27Plant for fall: Jul 28 to Aug 18
Sow outdoors: Apr 13 to May 25Plant for fall: Aug 11 to Sep 1
Start indoors: Apr 20 to Apr 27Transplant outside: Jun 1 to Jun 8Sow outdoors: May 25 to Jun 8Plant for fall: Jul 7 to Jul 21
Start indoors: Apr 20 to Apr 27Sow outdoors: May 25 to Jun 8Plant for fall: Jul 14 to Jul 28
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 30 to Jul 14
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 14 to Jul 28
Sow outdoors: Apr 27 to May 18
Sow outdoors: May 4 to Jun 1Plant for fall: Jul 14 to Jul 28
Sow outdoors: May 4 to May 25Plant for fall: Jul 28 to Aug 18
Sow outdoors: May 25 to Jun 15Plant for fall: Jul 7 to Jul 21
Sow outdoors: May 25 to Jun 8
Transplant outside: Jun 1 to Jun 22
Plant for fall: Sep 8 to Oct 13
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ashland, 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 28 – Aug 25 |
| Kale | Mar 23 – Apr 6 | Apr 20 – May 4 | Apr 20 – May 4 | Jul 14 – Aug 4 |
| Broccoli | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 16 – Jul 7 |
| Cabbage | Mar 23 – Apr 6 | Apr 27 – May 11 | — | Jun 16 – Jul 7 |
| Cauliflower | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 16 – Jul 7 |
| 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 30 – Jul 21 |
| Spinach | — | — | Apr 6 – Apr 27 | Jul 28 – Aug 18 |
| Radishes | — | — | Apr 13 – May 25 | Aug 11 – Sep 1 |
| Cucumbers | Apr 20 – Apr 27 | Jun 1 – Jun 8 | May 25 – Jun 8 | Jul 7 – Jul 21 |
| Zucchini & Summer Squash | Apr 20 – Apr 27 | — | May 25 – Jun 8 | Jul 14 – Jul 28 |
| 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 30 – Jul 14 |
| Beets | — | — | Apr 27 – May 25 | Jul 14 – Jul 28 |
| Potatoes | — | — | Apr 27 – May 18 | — |
| Swiss Chard | — | — | May 4 – Jun 1 | Jul 14 – Jul 28 |
| Cilantro | — | — | May 4 – May 25 | Jul 28 – Aug 18 |
| Green Beans | — | — | May 25 – Jun 15 | Jul 7 – Jul 21 |
| Sweet Corn | — | — | May 25 – Jun 8 | — |
| Sweet Potatoes | — | Jun 1 – Jun 22 | — | — |
| Garlic | — | — | — | Sep 8 – Oct 13 |
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 Brandenberg, MT weather station, 26 km away (elevation 2,769 ft (844 m)).
ZIP codes in Ashland: 59003 59004
Frost dates near Ashland
- Lame Deer May 23 · Sep 15
- Birney May 23 · Sep 15
- Busby May 23 · Sep 15
- Colstrip May 15 · Sep 30
- Volborg May 18 · Sep 22
- Otter May 14 · Sep 30
- Olive May 16 · Sep 28
- Decker May 18 · Sep 24
- Hathaway May 8 · Sep 30
- Forsyth May 9 · Sep 29
Frequently asked questions
When is the last frost in Ashland, MT?
The median last spring frost in Ashland, MT is May 18. There is still about a 10% chance of frost after May 30, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ashland, MT?
The median first fall frost is September 22, with about a 10% chance of frost before September 8.
How long is the growing season in Ashland, MT?
About 127 days between the median last spring frost and first fall frost.
What planting zone is Ashland, MT?
Ashland, MT is in USDA hardiness zone 4b.