Frost dates for 83702 — Boise, ID
Last spring frostApr 24median date
First fall frostOct 21median date
Growing season180 daysfrost-free
Hardiness zone7aZone 7a
How Boise compares
- In 8 years out of 10, the last spring frost in Boise falls between April 4 and May 9, a 35-day window. The first fall frost falls between October 5 and November 5.
- The median last frost is 20 days earlier than the Idaho median of May 14.
- Its 180-day growing season is longer than 95% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 8 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 108 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 4 |
| 50% (median) | April 24 |
| 10% (safe for tender plants) | May 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 5 |
| 50% (median) | October 21 |
| 90% (late) | November 5 |
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 83702 — Boise, ID — last frost Apr 24, first frost Oct 21, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Jan 30 to Feb 13Transplant outside: Mar 27 to Apr 10
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 27 to Mar 13Transplant outside: May 1 to May 15
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Sow outdoors: Mar 27 to May 1Plant for fall: Aug 26 to Sep 23
Start indoors: Feb 27 to Mar 13Transplant outside: Mar 27 to Apr 10Sow outdoors: Mar 27 to Apr 10Plant for fall: Aug 12 to Sep 2
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 15 to Aug 5
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Plant for fall: Jul 15 to Aug 5
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29Sow outdoors: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: May 1 to May 15
Sow outdoors: Mar 13 to Apr 3Plant for fall: Jul 29 to Aug 19
Sow outdoors: Mar 13 to Apr 3Plant for fall: Aug 26 to Sep 16
Sow outdoors: Mar 20 to May 1Plant for fall: Sep 9 to Sep 30
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 15Sow outdoors: May 1 to May 15Plant for fall: Aug 5 to Aug 19
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15Plant for fall: Aug 12 to Aug 26
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Apr 3 to May 1Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 12 to Aug 26
Sow outdoors: Apr 3 to Apr 24
Sow outdoors: Apr 10 to May 8Plant for fall: Aug 12 to Aug 26
Sow outdoors: Apr 10 to May 1Plant for fall: Aug 26 to Sep 16
Sow outdoors: May 1 to May 22Plant for fall: Aug 5 to Aug 19
Sow outdoors: May 1 to May 15
Transplant outside: May 8 to May 29
Plant for fall: Oct 7 to Nov 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Boise, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Peppers | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Tomatoes | Feb 27 – Mar 13 | May 1 – May 15 | — | — |
| Lettuce | Feb 27 – Mar 13 | Apr 3 – Apr 17 | Mar 27 – May 1 | Aug 26 – Sep 23 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 10 | Mar 27 – Apr 10 | Aug 12 – Sep 2 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 15 – Aug 5 |
| Cabbage | Feb 27 – Mar 13 | Apr 3 – Apr 17 | — | Jul 15 – Aug 5 |
| Cauliflower | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 15 – Aug 5 |
| Okra | Mar 13 – Mar 27 | May 15 – May 29 | May 15 – May 29 | — |
| Basil | Mar 13 – Mar 27 | May 1 – May 15 | — | — |
| Peas | — | — | Mar 13 – Apr 3 | Jul 29 – Aug 19 |
| Spinach | — | — | Mar 13 – Apr 3 | Aug 26 – Sep 16 |
| Radishes | — | — | Mar 20 – May 1 | Sep 9 – Sep 30 |
| Cucumbers | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 15 | Aug 5 – Aug 19 |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | — | May 1 – May 15 | Aug 12 – Aug 26 |
| Winter Squash & Pumpkins | Mar 27 – Apr 3 | — | May 1 – May 15 | — |
| Melons & Watermelon | Mar 27 – Apr 3 | May 8 – May 22 | — | — |
| Carrots | — | — | Apr 3 – May 1 | Jul 29 – Aug 12 |
| Beets | — | — | Apr 3 – May 1 | Aug 12 – Aug 26 |
| Potatoes | — | — | Apr 3 – Apr 24 | — |
| Swiss Chard | — | — | Apr 10 – May 8 | Aug 12 – Aug 26 |
| Cilantro | — | — | Apr 10 – May 1 | Aug 26 – Sep 16 |
| Green Beans | — | — | May 1 – May 22 | Aug 5 – Aug 19 |
| Sweet Corn | — | — | May 1 – May 15 | — |
| Sweet Potatoes | — | May 8 – May 29 | — | — |
| Garlic | — | — | — | Oct 7 – Nov 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 Boise Air Terminal, ID weather station, 8 km away (elevation 2,815 ft (858 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
- Kuna Apr 24 · Oct 21
- Mountain Home Afb Apr 30 · Oct 17
- Star Apr 29 · Oct 13
- Horseshoe Bend May 17 · Oct 12
- 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 April 24. There is still about a 10% chance of frost after May 9, 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 21, with about a 10% chance of frost before October 5.
How long is the growing season in Boise, ID?
About 180 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.