Frost dates for 83703 — Boise, ID
Last spring frostMay 17median date
First fall frostOct 12median date
Growing season148 daysfrost-free
Hardiness zone7aZone 7a
How Boise compares
- In 8 years out of 10, the last spring frost in Boise falls between April 27 and June 10, a 44-day window. The first fall frost falls between September 27 and October 30.
- The median last frost is 3 days later than the Idaho median of May 14.
- Its 148-day growing season is longer than 61% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 31 days later than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 125 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 27 |
| 50% (median) | May 17 |
| 10% (safe for tender plants) | June 10 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 27 |
| 50% (median) | October 12 |
| 90% (late) | October 30 |
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 Boise, ID
Frost dates for 83703 — Boise, ID — last frost May 17, first frost Oct 12, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 22 to Mar 8Transplant outside: Apr 19 to May 3
Start indoors: Mar 8 to Mar 22Transplant outside: May 31 to Jun 14
Start indoors: Mar 8 to Mar 22Transplant outside: May 31 to Jun 14
Start indoors: Mar 22 to Apr 5Transplant outside: May 24 to Jun 7
Start indoors: Mar 22 to Apr 5Transplant outside: Apr 26 to May 10Sow outdoors: Apr 19 to May 24Plant for fall: Aug 17 to Sep 14
Start indoors: Mar 22 to Apr 5Transplant outside: Apr 19 to May 3Sow outdoors: Apr 19 to May 3Plant for fall: Aug 3 to Aug 24
Start indoors: Mar 22 to Apr 5Transplant outside: May 3 to May 17Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 22 to Apr 5Transplant outside: Apr 26 to May 10Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 22 to Apr 5Transplant outside: May 3 to May 17Plant for fall: Jul 6 to Jul 27
Start indoors: Apr 5 to Apr 19Transplant outside: Jun 7 to Jun 21Sow outdoors: Jun 7 to Jun 21
Start indoors: Apr 5 to Apr 19Transplant outside: May 24 to Jun 7
Sow outdoors: Apr 5 to Apr 26Plant for fall: Jul 20 to Aug 10
Sow outdoors: Apr 5 to Apr 26Plant for fall: Aug 17 to Sep 7
Sow outdoors: Apr 12 to May 24Plant for fall: Aug 31 to Sep 21
Start indoors: Apr 19 to Apr 26Transplant outside: May 31 to Jun 7Sow outdoors: May 24 to Jun 7Plant for fall: Jul 27 to Aug 10
Start indoors: Apr 19 to Apr 26Sow outdoors: May 24 to Jun 7Plant for fall: Aug 3 to Aug 17
Start indoors: Apr 19 to Apr 26Sow outdoors: May 24 to Jun 7
Start indoors: Apr 19 to Apr 26Transplant outside: May 31 to Jun 14
Sow outdoors: Apr 26 to May 24Plant for fall: Jul 20 to Aug 3
Sow outdoors: Apr 26 to May 24Plant for fall: Aug 3 to Aug 17
Sow outdoors: Apr 26 to May 17
Sow outdoors: May 3 to May 31Plant for fall: Aug 3 to Aug 17
Sow outdoors: May 3 to May 24Plant for fall: Aug 17 to Sep 7
Sow outdoors: May 24 to Jun 14Plant for fall: Jul 27 to Aug 10
Sow outdoors: May 24 to Jun 7
Transplant outside: May 31 to Jun 21
Plant for fall: Sep 28 to Nov 2
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Boise, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 22 – Mar 8 | Apr 19 – May 3 | — | — |
| Peppers | Mar 8 – Mar 22 | May 31 – Jun 14 | — | — |
| Eggplant | Mar 8 – Mar 22 | May 31 – Jun 14 | — | — |
| Tomatoes | Mar 22 – Apr 5 | May 24 – Jun 7 | — | — |
| Lettuce | Mar 22 – Apr 5 | Apr 26 – May 10 | Apr 19 – May 24 | Aug 17 – Sep 14 |
| Kale | Mar 22 – Apr 5 | Apr 19 – May 3 | Apr 19 – May 3 | Aug 3 – Aug 24 |
| Broccoli | Mar 22 – Apr 5 | May 3 – May 17 | — | Jul 6 – Jul 27 |
| Cabbage | Mar 22 – Apr 5 | Apr 26 – May 10 | — | Jul 6 – Jul 27 |
| Cauliflower | Mar 22 – Apr 5 | May 3 – May 17 | — | Jul 6 – Jul 27 |
| Okra | Apr 5 – Apr 19 | Jun 7 – Jun 21 | Jun 7 – Jun 21 | — |
| Basil | Apr 5 – Apr 19 | May 24 – Jun 7 | — | — |
| Peas | — | — | Apr 5 – Apr 26 | Jul 20 – Aug 10 |
| Spinach | — | — | Apr 5 – Apr 26 | Aug 17 – Sep 7 |
| Radishes | — | — | Apr 12 – May 24 | Aug 31 – Sep 21 |
| Cucumbers | Apr 19 – Apr 26 | May 31 – Jun 7 | May 24 – Jun 7 | Jul 27 – Aug 10 |
| Zucchini & Summer Squash | Apr 19 – Apr 26 | — | May 24 – Jun 7 | Aug 3 – Aug 17 |
| Winter Squash & Pumpkins | Apr 19 – Apr 26 | — | May 24 – Jun 7 | — |
| Melons & Watermelon | Apr 19 – Apr 26 | May 31 – Jun 14 | — | — |
| Carrots | — | — | Apr 26 – May 24 | Jul 20 – Aug 3 |
| Beets | — | — | Apr 26 – May 24 | Aug 3 – Aug 17 |
| Potatoes | — | — | Apr 26 – May 17 | — |
| Swiss Chard | — | — | May 3 – May 31 | Aug 3 – Aug 17 |
| Cilantro | — | — | May 3 – May 24 | Aug 17 – Sep 7 |
| Green Beans | — | — | May 24 – Jun 14 | Jul 27 – Aug 10 |
| Sweet Corn | — | — | May 24 – Jun 7 | — |
| Sweet Potatoes | — | May 31 – Jun 21 | — | — |
| Garlic | — | — | — | Sep 28 – Nov 2 |
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 Boise 7 N, ID weather station, 10 km away (elevation 3,885 ft (1,184 m)).
ZIP codes in Boise: 83701 83702 83703 83704 83705 83706 83707 83708 83709 83711 83712 83713 83715 83716 83717 83719 83720 83722 83724 83725 83726 83728 83729 83731 83732 83735 83756 83799
Frost dates near Boise
- Garden City May 17 · Oct 12
- Eagle May 17 · Oct 12
- Meridian Apr 29 · Oct 13
- Mountain Home Afb Apr 30 · Oct 17
- Star Apr 29 · Oct 13
- Kuna Apr 24 · Oct 21
- Middleton Apr 29 · Oct 13
- Nampa Apr 29 · Oct 13
Frequently asked questions
When is the last frost in Boise, ID?
The median last spring frost in Boise, ID is May 17. There is still about a 10% chance of frost after June 10, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Boise, ID?
The median first fall frost is October 12, with about a 10% chance of frost before September 27.
How long is the growing season in Boise, ID?
About 148 days between the median last spring frost and first fall frost.
What planting zone is Boise, ID?
Boise, ID is in USDA hardiness zone 7a.