Frost dates for 83716 — Boise, ID
Last spring frostApr 30median date
First fall frostOct 22median date
Growing season175 daysfrost-free
Hardiness zone6bZone 6b
How Boise compares
- In 8 years out of 10, the last spring frost in Boise falls between April 11 and May 18, a 37-day window. The first fall frost falls between September 30 and November 6.
- The median last frost is 14 days earlier than the Idaho median of May 14.
- Its 175-day growing season is longer than 91% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 8 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b 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 11 |
| 50% (median) | April 30 |
| 10% (safe for tender plants) | May 18 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 30 |
| 50% (median) | October 22 |
| 90% (late) | November 6 |
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 83716 — Boise, ID — last frost Apr 30, first frost Oct 22, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Feb 5 to Feb 19Transplant outside: Apr 2 to Apr 16
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Mar 5 to Mar 19Transplant outside: May 7 to May 21
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 2 to May 7Plant for fall: Aug 27 to Sep 24
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 2 to Apr 16Sow outdoors: Apr 2 to Apr 16Plant for fall: Aug 13 to Sep 3
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 19 to Apr 2Transplant outside: May 21 to Jun 4Sow outdoors: May 21 to Jun 4
Start indoors: Mar 19 to Apr 2Transplant outside: May 7 to May 21
Sow outdoors: Mar 19 to Apr 9Plant for fall: Jul 30 to Aug 20
Sow outdoors: Mar 19 to Apr 9Plant for fall: Aug 27 to Sep 17
Sow outdoors: Mar 26 to May 7Plant for fall: Sep 10 to Oct 1
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 21Sow outdoors: May 7 to May 21Plant for fall: Aug 6 to Aug 20
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21Plant for fall: Aug 13 to Aug 27
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Apr 9 to May 7Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 9 to May 7Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 9 to Apr 30
Sow outdoors: Apr 16 to May 14Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 16 to May 7Plant for fall: Aug 27 to Sep 17
Sow outdoors: May 7 to May 28Plant for fall: Aug 6 to Aug 20
Sow outdoors: May 7 to May 21
Transplant outside: May 14 to Jun 4
Plant for fall: Oct 8 to Nov 12
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 5 – Feb 19 | Apr 2 – Apr 16 | — | — |
| Peppers | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Eggplant | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Tomatoes | Mar 5 – Mar 19 | May 7 – May 21 | — | — |
| Lettuce | Mar 5 – Mar 19 | Apr 9 – Apr 23 | Apr 2 – May 7 | Aug 27 – Sep 24 |
| Kale | Mar 5 – Mar 19 | Apr 2 – Apr 16 | Apr 2 – Apr 16 | Aug 13 – Sep 3 |
| Broccoli | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 16 – Aug 6 |
| Cabbage | Mar 5 – Mar 19 | Apr 9 – Apr 23 | — | Jul 16 – Aug 6 |
| Cauliflower | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 16 – Aug 6 |
| Okra | Mar 19 – Apr 2 | May 21 – Jun 4 | May 21 – Jun 4 | — |
| Basil | Mar 19 – Apr 2 | May 7 – May 21 | — | — |
| Peas | — | — | Mar 19 – Apr 9 | Jul 30 – Aug 20 |
| Spinach | — | — | Mar 19 – Apr 9 | Aug 27 – Sep 17 |
| Radishes | — | — | Mar 26 – May 7 | Sep 10 – Oct 1 |
| Cucumbers | Apr 2 – Apr 9 | May 14 – May 21 | May 7 – May 21 | Aug 6 – Aug 20 |
| Zucchini & Summer Squash | Apr 2 – Apr 9 | — | May 7 – May 21 | Aug 13 – Aug 27 |
| Winter Squash & Pumpkins | Apr 2 – Apr 9 | — | May 7 – May 21 | — |
| Melons & Watermelon | Apr 2 – Apr 9 | May 14 – May 28 | — | — |
| Carrots | — | — | Apr 9 – May 7 | Jul 30 – Aug 13 |
| Beets | — | — | Apr 9 – May 7 | Aug 13 – Aug 27 |
| Potatoes | — | — | Apr 9 – Apr 30 | — |
| Swiss Chard | — | — | Apr 16 – May 14 | Aug 13 – Aug 27 |
| Cilantro | — | — | Apr 16 – May 7 | Aug 27 – Sep 17 |
| Green Beans | — | — | May 7 – May 28 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | May 7 – May 21 | — |
| Sweet Potatoes | — | May 14 – Jun 4 | — | — |
| Garlic | — | — | — | Oct 8 – Nov 12 |
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 Lucky Peak Dam, ID weather station, 7 km away (elevation 2,841 ft (866 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
- Kuna Apr 24 · Oct 21
- Meridian Apr 29 · Oct 13
- Eagle May 17 · Oct 12
- Idaho City Jun 17 · Sep 5
- Mountain Home Afb Apr 30 · Oct 17
- Star Apr 29 · Oct 13
- Horseshoe Bend May 17 · Oct 12
Frequently asked questions
When is the last frost in Boise, ID?
The median last spring frost in Boise, ID is April 30. There is still about a 10% chance of frost after May 18, 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 22, with about a 10% chance of frost before September 30.
How long is the growing season in Boise, ID?
About 175 days between the median last spring frost and first fall frost.
What planting zone is Boise, ID?
Boise, ID is in USDA hardiness zone 6b.