Alzada, MT frost dates
Last spring frostJun 2median date
First fall frostSep 6median date
Growing season96 daysfrost-free
Hardiness zone4bZone 4b
How Alzada compares
- In 8 years out of 10, the last spring frost in Alzada falls between May 18 and June 21, a 34-day window. The first fall frost falls between August 23 and September 20.
- The median last frost is 14 days later than the Montana median of May 19.
- Its 96-day growing season is longer than 9% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 25 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 198 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 18 |
| 50% (median) | June 2 |
| 10% (safe for tender plants) | June 21 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 23 |
| 50% (median) | September 6 |
| 90% (late) | September 20 |
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 Alzada, MT
Alzada, MT frost dates — last frost Jun 2, first frost Sep 6, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Mar 10 to Mar 24Transplant outside: May 5 to May 19
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Apr 7 to Apr 21Transplant outside: Jun 9 to Jun 23
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26Sow outdoors: May 5 to Jun 9Plant for fall: Jul 12 to Aug 9
Start indoors: Apr 7 to Apr 21Transplant outside: May 5 to May 19Sow outdoors: May 5 to May 19Plant for fall: Jun 28 to Jul 19
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2
Start indoors: Apr 21 to May 5Transplant outside: Jun 23 to Jul 7Sow outdoors: Jun 23 to Jul 7
Start indoors: Apr 21 to May 5Transplant outside: Jun 9 to Jun 23
Sow outdoors: Apr 21 to May 12
Sow outdoors: Apr 21 to May 12Plant for fall: Jul 12 to Aug 2
Sow outdoors: Apr 28 to Jun 9Plant for fall: Jul 26 to Aug 16
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 23Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 30
Sow outdoors: May 12 to Jun 9
Sow outdoors: May 12 to Jun 9Plant for fall: Jun 28 to Jul 12
Sow outdoors: May 12 to Jun 2
Sow outdoors: May 19 to Jun 16
Sow outdoors: May 19 to Jun 9Plant for fall: Jul 12 to Aug 2
Sow outdoors: Jun 9 to Jun 30
Sow outdoors: Jun 9 to Jun 23
Transplant outside: Jun 16 to Jul 7
Plant for fall: Aug 23 to Sep 27
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Alzada, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 10 – Mar 24 | May 5 – May 19 | — | — |
| Peppers | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Eggplant | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Tomatoes | Apr 7 – Apr 21 | Jun 9 – Jun 23 | — | — |
| Lettuce | Apr 7 – Apr 21 | May 12 – May 26 | May 5 – Jun 9 | Jul 12 – Aug 9 |
| Kale | Apr 7 – Apr 21 | May 5 – May 19 | May 5 – May 19 | Jun 28 – Jul 19 |
| Broccoli | Apr 7 – Apr 21 | May 19 – Jun 2 | — | — |
| Cabbage | Apr 7 – Apr 21 | May 12 – May 26 | — | — |
| Cauliflower | Apr 7 – Apr 21 | May 19 – Jun 2 | — | — |
| Okra | Apr 21 – May 5 | Jun 23 – Jul 7 | Jun 23 – Jul 7 | — |
| Basil | Apr 21 – May 5 | Jun 9 – Jun 23 | — | — |
| Peas | — | — | Apr 21 – May 12 | — |
| Spinach | — | — | Apr 21 – May 12 | Jul 12 – Aug 2 |
| Radishes | — | — | Apr 28 – Jun 9 | Jul 26 – Aug 16 |
| Cucumbers | May 5 – May 12 | Jun 16 – Jun 23 | Jun 9 – Jun 23 | — |
| Zucchini & Summer Squash | May 5 – May 12 | — | Jun 9 – Jun 23 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 96 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 5 – May 12 | — | Jun 9 – Jun 23 | — |
| Melons & Watermelon Warning: Your frost-free season is about 96 days, which is tight for melons & watermelon (85+ days). Choose early varieties and use transplants or row covers. | May 5 – May 12 | Jun 16 – Jun 30 | — | — |
| Carrots | — | — | May 12 – Jun 9 | — |
| Beets | — | — | May 12 – Jun 9 | Jun 28 – Jul 12 |
| Potatoes | — | — | May 12 – Jun 2 | — |
| Swiss Chard | — | — | May 19 – Jun 16 | — |
| Cilantro | — | — | May 19 – Jun 9 | Jul 12 – Aug 2 |
| Green Beans | — | — | Jun 9 – Jun 30 | — |
| Sweet Corn | — | — | Jun 9 – Jun 23 | — |
| Sweet Potatoes Warning: Your frost-free season is about 96 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 16 – Jul 7 | — | — |
| Garlic | — | — | — | Aug 23 – Sep 27 |
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 Albion 1 N, MT weather station, 6 km away (elevation 3,314 ft (1,010 m)).
Frost dates near Alzada
- Capitol May 17 · Sep 24
- Hammond May 17 · Sep 22
- Boyes May 16 · Sep 28
- Broadus May 16 · Sep 28
- Ekalaka May 20 · Sep 23
- Biddle May 14 · Sep 28
- Powderville May 13 · Sep 25
- Olive May 16 · Sep 28
- Willard May 12 · Sep 26
- Baker May 16 · Sep 26
Frequently asked questions
When is the last frost in Alzada, MT?
The median last spring frost in Alzada, MT is June 2. There is still about a 10% chance of frost after June 21, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Alzada, MT?
The median first fall frost is September 6, with about a 10% chance of frost before August 23.
How long is the growing season in Alzada, MT?
About 96 days between the median last spring frost and first fall frost.
What planting zone is Alzada, MT?
Alzada, MT is in USDA hardiness zone 4b.