Silver Star, MT frost dates
Last spring frostJun 8median date
First fall frostSep 2median date
Growing season86 daysfrost-free
Hardiness zone5aZone 5a
How Silver Star compares
- In 8 years out of 10, the last spring frost in Silver Star falls between May 22 and July 1, a 40-day window. The first fall frost falls between August 16 and September 15.
- The median last frost is 20 days later than the Montana median of May 19.
- Its 86-day growing season is among the shortest of the 325 Montana places with a regular frost season.
- The last frost is 36 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 206 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 22 |
| 50% (median) | June 8 |
| 10% (safe for tender plants) | July 1 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 16 |
| 50% (median) | September 2 |
| 90% (late) | September 15 |
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 Silver Star, MT
Silver Star, MT frost dates — last frost Jun 8, first frost Sep 2, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Mar 16 to Mar 30Transplant outside: May 11 to May 25
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 22 to Jul 6
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 22 to Jul 6
Start indoors: Apr 13 to Apr 27Transplant outside: Jun 15 to Jun 29
Start indoors: Apr 13 to Apr 27Transplant outside: May 18 to Jun 1Sow outdoors: May 11 to Jun 15Plant for fall: Jul 8 to Aug 5
Start indoors: Apr 13 to Apr 27Transplant outside: May 11 to May 25Sow outdoors: May 11 to May 25Plant for fall: Jun 24 to Jul 15
Start indoors: Apr 13 to Apr 27Transplant outside: May 25 to Jun 8
Start indoors: Apr 13 to Apr 27Transplant outside: May 18 to Jun 1
Start indoors: Apr 13 to Apr 27Transplant outside: May 25 to Jun 8
Start indoors: Apr 27 to May 11Transplant outside: Jun 29 to Jul 13Sow outdoors: Jun 29 to Jul 13
Start indoors: Apr 27 to May 11Transplant outside: Jun 15 to Jun 29
Sow outdoors: Apr 27 to May 18
Sow outdoors: Apr 27 to May 18Plant for fall: Jul 8 to Jul 29
Sow outdoors: May 4 to Jun 15Plant for fall: Jul 22 to Aug 12
Start indoors: May 11 to May 18Transplant outside: Jun 22 to Jun 29Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Transplant outside: Jun 22 to Jul 6
Sow outdoors: May 18 to Jun 15
Sow outdoors: May 18 to Jun 15
Sow outdoors: May 18 to Jun 8
Sow outdoors: May 25 to Jun 22
Sow outdoors: May 25 to Jun 15Plant for fall: Jul 8 to Jul 29
Sow outdoors: Jun 15 to Jul 6
Sow outdoors: Jun 15 to Jun 29
Transplant outside: Jun 22 to Jul 13
Plant for fall: Aug 19 to Sep 23
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Silver Star, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 16 – Mar 30 | May 11 – May 25 | — | — |
| Peppers Warning: Your frost-free season is about 86 days, which is tight for peppers (75+ days). Choose early varieties and use transplants or row covers. | Mar 30 – Apr 13 | Jun 22 – Jul 6 | — | — |
| Eggplant Warning: Your frost-free season is about 86 days, which is tight for eggplant (75+ days). Choose early varieties and use transplants or row covers. | Mar 30 – Apr 13 | Jun 22 – Jul 6 | — | — |
| Tomatoes | Apr 13 – Apr 27 | Jun 15 – Jun 29 | — | — |
| Lettuce | Apr 13 – Apr 27 | May 18 – Jun 1 | May 11 – Jun 15 | Jul 8 – Aug 5 |
| Kale | Apr 13 – Apr 27 | May 11 – May 25 | May 11 – May 25 | Jun 24 – Jul 15 |
| Broccoli | Apr 13 – Apr 27 | May 25 – Jun 8 | — | — |
| Cabbage | Apr 13 – Apr 27 | May 18 – Jun 1 | — | — |
| Cauliflower | Apr 13 – Apr 27 | May 25 – Jun 8 | — | — |
| Okra | Apr 27 – May 11 | Jun 29 – Jul 13 | Jun 29 – Jul 13 | — |
| Basil | Apr 27 – May 11 | Jun 15 – Jun 29 | — | — |
| Peas | — | — | Apr 27 – May 18 | — |
| Spinach | — | — | Apr 27 – May 18 | Jul 8 – Jul 29 |
| Radishes | — | — | May 4 – Jun 15 | Jul 22 – Aug 12 |
| Cucumbers | May 11 – May 18 | Jun 22 – Jun 29 | Jun 15 – Jun 29 | — |
| Zucchini & Summer Squash | May 11 – May 18 | — | Jun 15 – Jun 29 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 86 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 11 – May 18 | — | Jun 15 – Jun 29 | — |
| Melons & Watermelon Warning: Your frost-free season is about 86 days, which is tight for melons & watermelon (85+ days). Choose early varieties and use transplants or row covers. | May 11 – May 18 | Jun 22 – Jul 6 | — | — |
| Carrots | — | — | May 18 – Jun 15 | — |
| Beets | — | — | May 18 – Jun 15 | — |
| Potatoes | — | — | May 18 – Jun 8 | — |
| Swiss Chard | — | — | May 25 – Jun 22 | — |
| Cilantro | — | — | May 25 – Jun 15 | Jul 8 – Jul 29 |
| Green Beans | — | — | Jun 15 – Jul 6 | — |
| Sweet Corn Warning: Your frost-free season is about 86 days, which is tight for sweet corn (80+ days). Choose early varieties and use transplants or row covers. | — | — | Jun 15 – Jun 29 | — |
| Sweet Potatoes Warning: Your frost-free season is about 86 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 22 – Jul 13 | — | — |
| Garlic | — | — | — | Aug 19 – Sep 23 |
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 Twin Bridges, MT weather station, 18 km away (elevation 4,626 ft (1,410 m)).
Frost dates near Silver Star
- Twin Bridges Jun 8 · Sep 2
- Whitehall Jun 13 · Sep 5
- Pony Apr 30 · Oct 10
- Sheridan May 24 · Sep 22
- Harrison Apr 30 · Oct 10
- Melrose frost any month
- Butte Jun 13 · Sep 5
- Glen frost any month
- Cardwell May 9 · Sep 27
- Divide Jun 10 · Sep 7
Frequently asked questions
When is the last frost in Silver Star, MT?
The median last spring frost in Silver Star, MT is June 8. There is still about a 10% chance of frost after July 1, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Silver Star, MT?
The median first fall frost is September 2, with about a 10% chance of frost before August 16.
How long is the growing season in Silver Star, MT?
About 86 days between the median last spring frost and first fall frost.
What planting zone is Silver Star, MT?
Silver Star, MT is in USDA hardiness zone 5a.