Florence, MT frost dates
Last spring frostMay 22median date
First fall frostSep 19median date
Growing season120 daysfrost-free
Hardiness zone5bZone 5b
How Florence compares
- In 8 years out of 10, the last spring frost in Florence falls between May 7 and June 13, a 37-day window. The first fall frost falls between September 3 and October 2.
- The median last frost is 3 days later than the Montana median of May 19.
- Its 120-day growing season is longer than 34% of the 325 Montana places with a regular frost season (state median 125 days).
- The last frost is 21 days later than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 175 nights a year at or below 32°F.
- Compared with Missoula, MT, 28 km away, the last frost here is 12 days later than there and the growing season is 24 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 7 |
| 50% (median) | May 22 |
| 10% (safe for tender plants) | June 13 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 3 |
| 50% (median) | September 19 |
| 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 Florence, MT
Florence, MT frost dates — last frost May 22, first frost Sep 19, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Feb 27 to Mar 13Transplant outside: Apr 24 to May 8
Start indoors: Mar 13 to Mar 27Transplant outside: Jun 5 to Jun 19
Start indoors: Mar 13 to Mar 27Transplant outside: Jun 5 to Jun 19
Start indoors: Mar 27 to Apr 10Transplant outside: May 29 to Jun 12
Start indoors: Mar 27 to Apr 10Transplant outside: May 1 to May 15Sow outdoors: Apr 24 to May 29Plant for fall: Jul 25 to Aug 22
Start indoors: Mar 27 to Apr 10Transplant outside: Apr 24 to May 8Sow outdoors: Apr 24 to May 8Plant for fall: Jul 11 to Aug 1
Start indoors: Mar 27 to Apr 10Transplant outside: May 8 to May 22Plant for fall: Jun 13 to Jul 4
Start indoors: Mar 27 to Apr 10Transplant outside: May 1 to May 15Plant for fall: Jun 13 to Jul 4
Start indoors: Mar 27 to Apr 10Transplant outside: May 8 to May 22Plant for fall: Jun 13 to Jul 4
Start indoors: Apr 10 to Apr 24Transplant outside: Jun 12 to Jun 26Sow outdoors: Jun 12 to Jun 26
Start indoors: Apr 10 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 10 to May 1Plant for fall: Jun 27 to Jul 18
Sow outdoors: Apr 10 to May 1Plant for fall: Jul 25 to Aug 15
Sow outdoors: Apr 17 to May 29Plant for fall: Aug 8 to Aug 29
Start indoors: Apr 24 to May 1Transplant outside: Jun 5 to Jun 12Sow outdoors: May 29 to Jun 12Plant for fall: Jul 4 to Jul 18
Start indoors: Apr 24 to May 1Sow outdoors: May 29 to Jun 12Plant for fall: Jul 11 to Jul 25
Start indoors: Apr 24 to May 1Sow outdoors: May 29 to Jun 12
Start indoors: Apr 24 to May 1Transplant outside: Jun 5 to Jun 19
Sow outdoors: May 1 to May 29Plant for fall: Jun 27 to Jul 11
Sow outdoors: May 1 to May 29Plant for fall: Jul 11 to Jul 25
Sow outdoors: May 1 to May 22
Sow outdoors: May 8 to Jun 5Plant for fall: Jul 11 to Jul 25
Sow outdoors: May 8 to May 29Plant for fall: Jul 25 to Aug 15
Sow outdoors: May 29 to Jun 19Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 29 to Jun 12
Transplant outside: Jun 5 to Jun 26
Plant for fall: Sep 5 to Oct 10
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Florence, MT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 27 – Mar 13 | Apr 24 – May 8 | — | — |
| Peppers | Mar 13 – Mar 27 | Jun 5 – Jun 19 | — | — |
| Eggplant | Mar 13 – Mar 27 | Jun 5 – Jun 19 | — | — |
| Tomatoes | Mar 27 – Apr 10 | May 29 – Jun 12 | — | — |
| Lettuce | Mar 27 – Apr 10 | May 1 – May 15 | Apr 24 – May 29 | Jul 25 – Aug 22 |
| Kale | Mar 27 – Apr 10 | Apr 24 – May 8 | Apr 24 – May 8 | Jul 11 – Aug 1 |
| Broccoli | Mar 27 – Apr 10 | May 8 – May 22 | — | Jun 13 – Jul 4 |
| Cabbage | Mar 27 – Apr 10 | May 1 – May 15 | — | Jun 13 – Jul 4 |
| Cauliflower | Mar 27 – Apr 10 | May 8 – May 22 | — | Jun 13 – Jul 4 |
| Okra | Apr 10 – Apr 24 | Jun 12 – Jun 26 | Jun 12 – Jun 26 | — |
| Basil | Apr 10 – Apr 24 | May 29 – Jun 12 | — | — |
| Peas | — | — | Apr 10 – May 1 | Jun 27 – Jul 18 |
| Spinach | — | — | Apr 10 – May 1 | Jul 25 – Aug 15 |
| Radishes | — | — | Apr 17 – May 29 | Aug 8 – Aug 29 |
| Cucumbers | Apr 24 – May 1 | Jun 5 – Jun 12 | May 29 – Jun 12 | Jul 4 – Jul 18 |
| Zucchini & Summer Squash | Apr 24 – May 1 | — | May 29 – Jun 12 | Jul 11 – Jul 25 |
| Winter Squash & Pumpkins | Apr 24 – May 1 | — | May 29 – Jun 12 | — |
| Melons & Watermelon | Apr 24 – May 1 | Jun 5 – Jun 19 | — | — |
| Carrots | — | — | May 1 – May 29 | Jun 27 – Jul 11 |
| Beets | — | — | May 1 – May 29 | Jul 11 – Jul 25 |
| Potatoes | — | — | May 1 – May 22 | — |
| Swiss Chard | — | — | May 8 – Jun 5 | Jul 11 – Jul 25 |
| Cilantro | — | — | May 8 – May 29 | Jul 25 – Aug 15 |
| Green Beans | — | — | May 29 – Jun 19 | Jul 4 – Jul 18 |
| Sweet Corn | — | — | May 29 – Jun 12 | — |
| Sweet Potatoes | — | Jun 5 – Jun 26 | — | — |
| Garlic | — | — | — | Sep 5 – Oct 10 |
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 Stevensville, MT weather station, 13 km away (elevation 3,376 ft (1,029 m)).
Frost dates near Florence
- Stevensville May 22 · Sep 19
- Lolo May 16 · Sep 26
- Victor May 23 · Sep 21
- Missoula May 10 · Oct 1
- Milltown May 10 · Oct 1
- Bonner May 10 · Oct 1
- Clinton frost any month
- Pinesdale May 21 · Sep 22
- Corvallis May 23 · Sep 21
- Hamilton May 21 · Sep 22
Frequently asked questions
When is the last frost in Florence, MT?
The median last spring frost in Florence, MT is May 22. There is still about a 10% chance of frost after June 13, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Florence, MT?
The median first fall frost is September 19, with about a 10% chance of frost before September 3.
How long is the growing season in Florence, MT?
About 120 days between the median last spring frost and first fall frost.
What planting zone is Florence, MT?
Florence, MT is in USDA hardiness zone 5b.