Frost dates for 83403 — Idaho Falls, ID
Last spring frostMay 9median date
First fall frostOct 1median date
Growing season145 daysfrost-free
Hardiness zone5bZone 5b
How Idaho Falls compares
- In 8 years out of 10, the last spring frost in Idaho Falls falls between April 27 and June 2, a 36-day window. The first fall frost falls between September 17 and October 15.
- The median last frost is 5 days earlier than the Idaho median of May 14.
- Its 145-day growing season is longer than 57% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 8 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 166 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 27 |
| 50% (median) | May 9 |
| 10% (safe for tender plants) | June 2 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 17 |
| 50% (median) | October 1 |
| 90% (late) | October 15 |
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 Idaho Falls, ID
Frost dates for 83403 — Idaho Falls, ID — last frost May 9, first frost Oct 1, zone 5b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 14 to Feb 28Transplant outside: Apr 11 to Apr 25
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Sow outdoors: Apr 11 to May 16Plant for fall: Aug 6 to Sep 3
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 11 to Apr 25Plant for fall: Jul 23 to Aug 13
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13Sow outdoors: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Jul 9 to Jul 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Aug 6 to Aug 27
Sow outdoors: Apr 4 to May 16Plant for fall: Aug 20 to Sep 10
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to May 30Sow outdoors: May 16 to May 30Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 9 to Jul 23
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 18 to May 9
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 6 to Aug 27
Sow outdoors: May 16 to Jun 6Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 16 to May 30
Transplant outside: May 23 to Jun 13
Plant for fall: Sep 17 to Oct 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Idaho Falls, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 14 – Feb 28 | Apr 11 – Apr 25 | — | — |
| Peppers | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Eggplant | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Tomatoes | Mar 14 – Mar 28 | May 16 – May 30 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 18 – May 2 | Apr 11 – May 16 | Aug 6 – Sep 3 |
| Kale | Mar 14 – Mar 28 | Apr 11 – Apr 25 | Apr 11 – Apr 25 | Jul 23 – Aug 13 |
| Broccoli | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 25 – Jul 16 |
| Cabbage | Mar 14 – Mar 28 | Apr 18 – May 2 | — | Jun 25 – Jul 16 |
| Cauliflower | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 25 – Jul 16 |
| Okra | Mar 28 – Apr 11 | May 30 – Jun 13 | May 30 – Jun 13 | — |
| Basil | Mar 28 – Apr 11 | May 16 – May 30 | — | — |
| Peas | — | — | Mar 28 – Apr 18 | Jul 9 – Jul 30 |
| Spinach | — | — | Mar 28 – Apr 18 | Aug 6 – Aug 27 |
| Radishes | — | — | Apr 4 – May 16 | Aug 20 – Sep 10 |
| Cucumbers | Apr 11 – Apr 18 | May 23 – May 30 | May 16 – May 30 | Jul 16 – Jul 30 |
| Zucchini & Summer Squash | Apr 11 – Apr 18 | — | May 16 – May 30 | Jul 23 – Aug 6 |
| Winter Squash & Pumpkins | Apr 11 – Apr 18 | — | May 16 – May 30 | — |
| Melons & Watermelon | Apr 11 – Apr 18 | May 23 – Jun 6 | — | — |
| Carrots | — | — | Apr 18 – May 16 | Jul 9 – Jul 23 |
| Beets | — | — | Apr 18 – May 16 | Jul 23 – Aug 6 |
| Potatoes | — | — | Apr 18 – May 9 | — |
| Swiss Chard | — | — | Apr 25 – May 23 | Jul 23 – Aug 6 |
| Cilantro | — | — | Apr 25 – May 16 | Aug 6 – Aug 27 |
| Green Beans | — | — | May 16 – Jun 6 | Jul 16 – Jul 30 |
| Sweet Corn | — | — | May 16 – May 30 | — |
| Sweet Potatoes | — | May 23 – Jun 13 | — | — |
| Garlic | — | — | — | Sep 17 – Oct 22 |
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 Idaho Falls - Kifi, ID weather station, 6 km away (elevation 4,741 ft (1,445 m)).
ZIP codes in Idaho Falls: 83401 83402 83403 83404 83405 83406 83415
Frost dates near Idaho Falls
- Iona May 9 · Oct 1
- Shelley May 23 · Sep 20
- Ucon May 9 · Oct 5
- Basalt May 5 · Oct 3
- Firth May 5 · Oct 3
- Lewisville May 9 · Oct 5
- Rigby May 9 · Oct 5
- Roberts May 9 · Oct 5
Frequently asked questions
When is the last frost in Idaho Falls, ID?
The median last spring frost in Idaho Falls, ID is May 9. There is still about a 10% chance of frost after June 2, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Idaho Falls, ID?
The median first fall frost is October 1, with about a 10% chance of frost before September 17.
How long is the growing season in Idaho Falls, ID?
About 145 days between the median last spring frost and first fall frost.
What planting zone is Idaho Falls, ID?
Idaho Falls, ID is in USDA hardiness zone 5b.