Hobson, MT frost dates
Last spring frostMay 28median date
First fall frostSep 20median date
Growing season115 daysfrost-free
Hardiness zone4bZone 4b
How Hobson compares
- In 8 years out of 10, the last spring frost in Hobson falls between May 13 and June 19, a 37-day window. The first fall frost falls between September 4 and October 2.
- The median last frost is 9 days later than the Montana median of May 19.
- Its 115-day growing season is longer than 28% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 20 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 182 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 13 |
| 50% (median) | May 28 |
| 10% (safe for tender plants) | June 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 4 |
| 50% (median) | September 20 |
| 90% (late) | October 2 |
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 Hobson, MT
Hobson, MT frost dates — last frost May 28, first frost Sep 20, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Mar 5 to Mar 19Transplant outside: Apr 30 to May 14
Start indoors: Mar 19 to Apr 2Transplant outside: Jun 11 to Jun 25
Start indoors: Mar 19 to Apr 2Transplant outside: Jun 11 to Jun 25
Start indoors: Apr 2 to Apr 16Transplant outside: Jun 4 to Jun 18
Start indoors: Apr 2 to Apr 16Transplant outside: May 7 to May 21Sow outdoors: Apr 30 to Jun 4Plant for fall: Jul 26 to Aug 23
Start indoors: Apr 2 to Apr 16Transplant outside: Apr 30 to May 14Sow outdoors: Apr 30 to May 14Plant for fall: Jul 12 to Aug 2
Start indoors: Apr 2 to Apr 16Transplant outside: May 14 to May 28Plant for fall: Jun 14 to Jul 5
Start indoors: Apr 2 to Apr 16Transplant outside: May 7 to May 21Plant for fall: Jun 14 to Jul 5
Start indoors: Apr 2 to Apr 16Transplant outside: May 14 to May 28Plant for fall: Jun 14 to Jul 5
Start indoors: Apr 16 to Apr 30Transplant outside: Jun 18 to Jul 2Sow outdoors: Jun 18 to Jul 2
Start indoors: Apr 16 to Apr 30Transplant outside: Jun 4 to Jun 18
Sow outdoors: Apr 16 to May 7Plant for fall: Jun 28 to Jul 19
Sow outdoors: Apr 16 to May 7Plant for fall: Jul 26 to Aug 16
Sow outdoors: Apr 23 to Jun 4Plant for fall: Aug 9 to Aug 30
Start indoors: Apr 30 to May 7Transplant outside: Jun 11 to Jun 18Sow outdoors: Jun 4 to Jun 18Plant for fall: Jul 5 to Jul 19
Start indoors: Apr 30 to May 7Sow outdoors: Jun 4 to Jun 18Plant for fall: Jul 12 to Jul 26
Start indoors: Apr 30 to May 7Sow outdoors: Jun 4 to Jun 18
Start indoors: Apr 30 to May 7Transplant outside: Jun 11 to Jun 25
Sow outdoors: May 7 to Jun 4Plant for fall: Jun 28 to Jul 12
Sow outdoors: May 7 to Jun 4Plant for fall: Jul 12 to Jul 26
Sow outdoors: May 7 to May 28
Sow outdoors: May 14 to Jun 11Plant for fall: Jul 12 to Jul 26
Sow outdoors: May 14 to Jun 4Plant for fall: Jul 26 to Aug 16
Sow outdoors: Jun 4 to Jun 25
Sow outdoors: Jun 4 to Jun 18
Transplant outside: Jun 11 to Jul 2
Plant for fall: Sep 6 to Oct 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Hobson, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 5 – Mar 19 | Apr 30 – May 14 | — | — |
| Peppers | Mar 19 – Apr 2 | Jun 11 – Jun 25 | — | — |
| Eggplant | Mar 19 – Apr 2 | Jun 11 – Jun 25 | — | — |
| Tomatoes | Apr 2 – Apr 16 | Jun 4 – Jun 18 | — | — |
| Lettuce | Apr 2 – Apr 16 | May 7 – May 21 | Apr 30 – Jun 4 | Jul 26 – Aug 23 |
| Kale | Apr 2 – Apr 16 | Apr 30 – May 14 | Apr 30 – May 14 | Jul 12 – Aug 2 |
| Broccoli | Apr 2 – Apr 16 | May 14 – May 28 | — | Jun 14 – Jul 5 |
| Cabbage | Apr 2 – Apr 16 | May 7 – May 21 | — | Jun 14 – Jul 5 |
| Cauliflower | Apr 2 – Apr 16 | May 14 – May 28 | — | Jun 14 – Jul 5 |
| Okra | Apr 16 – Apr 30 | Jun 18 – Jul 2 | Jun 18 – Jul 2 | — |
| Basil | Apr 16 – Apr 30 | Jun 4 – Jun 18 | — | — |
| Peas | — | — | Apr 16 – May 7 | Jun 28 – Jul 19 |
| Spinach | — | — | Apr 16 – May 7 | Jul 26 – Aug 16 |
| Radishes | — | — | Apr 23 – Jun 4 | Aug 9 – Aug 30 |
| Cucumbers | Apr 30 – May 7 | Jun 11 – Jun 18 | Jun 4 – Jun 18 | Jul 5 – Jul 19 |
| Zucchini & Summer Squash | Apr 30 – May 7 | — | Jun 4 – Jun 18 | Jul 12 – Jul 26 |
| Winter Squash & Pumpkins | Apr 30 – May 7 | — | Jun 4 – Jun 18 | — |
| Melons & Watermelon | Apr 30 – May 7 | Jun 11 – Jun 25 | — | — |
| Carrots | — | — | May 7 – Jun 4 | Jun 28 – Jul 12 |
| Beets | — | — | May 7 – Jun 4 | Jul 12 – Jul 26 |
| Potatoes | — | — | May 7 – May 28 | — |
| Swiss Chard | — | — | May 14 – Jun 11 | Jul 12 – Jul 26 |
| Cilantro | — | — | May 14 – Jun 4 | Jul 26 – Aug 16 |
| Green Beans | — | — | Jun 4 – Jun 25 | — |
| Sweet Corn | — | — | Jun 4 – Jun 18 | — |
| Sweet Potatoes | — | Jun 11 – Jul 2 | — | — |
| 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 Moccasin Exp Stn, MT weather station, 9 km away (elevation 4,301 ft (1,311 m)).
Frost dates near Hobson
- Moccasin May 28 · Sep 20
- Moore May 23 · Sep 21
- Buffalo Jun 1 · Sep 15
- Stanford May 25 · Sep 21
- Lewistown May 14 · Sep 28
- Denton Jun 1 · Sep 11
- Judith Gap Jun 1 · Sep 15
- Coffee Creek Jun 1 · Sep 11
- Hilger May 14 · Sep 28
- Geyser May 22 · Sep 23
Frequently asked questions
When is the last frost in Hobson, MT?
The median last spring frost in Hobson, MT is May 28. There is still about a 10% chance of frost after June 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Hobson, MT?
The median first fall frost is September 20, with about a 10% chance of frost before September 4.
How long is the growing season in Hobson, MT?
About 115 days between the median last spring frost and first fall frost.
What planting zone is Hobson, MT?
Hobson, MT is in USDA hardiness zone 4b.