Frost dates for 83605 — Caldwell, ID
Last spring frostApr 23median date
First fall frostOct 18median date
Growing season178 daysfrost-free
Hardiness zone7aZone 7a
How Caldwell compares
- In 8 years out of 10, the last spring frost in Caldwell falls between April 5 and May 9, a 34-day window. The first fall frost falls between October 2 and November 1.
- The median last frost is 21 days earlier than the Idaho median of May 14.
- Its 178-day growing season is longer than 92% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 7 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 106 nights a year at or below 32°F.
- Compared with Nampa, ID, 10 km away, the last frost here is 6 days earlier than there and the growing season is 11 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 5 |
| 50% (median) | April 23 |
| 10% (safe for tender plants) | May 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 2 |
| 50% (median) | October 18 |
| 90% (late) | November 1 |
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 Caldwell, ID
Frost dates for 83605 — Caldwell, ID — last frost Apr 23, first frost Oct 18, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Jan 29 to Feb 12Transplant outside: Mar 26 to Apr 9
Start indoors: Feb 12 to Feb 26Transplant outside: May 7 to May 21
Start indoors: Feb 12 to Feb 26Transplant outside: May 7 to May 21
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 30 to May 14
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 2 to Apr 16Sow outdoors: Mar 26 to Apr 30Plant for fall: Aug 23 to Sep 20
Start indoors: Feb 26 to Mar 12Transplant outside: Mar 26 to Apr 9Sow outdoors: Mar 26 to Apr 9Plant for fall: Aug 9 to Aug 30
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 9 to Apr 23Plant for fall: Jul 12 to Aug 2
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 2 to Apr 16Plant for fall: Jul 12 to Aug 2
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 9 to Apr 23Plant for fall: Jul 12 to Aug 2
Start indoors: Mar 12 to Mar 26Transplant outside: May 14 to May 28Sow outdoors: May 14 to May 28
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 30 to May 14
Sow outdoors: Mar 12 to Apr 2Plant for fall: Jul 26 to Aug 16
Sow outdoors: Mar 12 to Apr 2Plant for fall: Aug 23 to Sep 13
Sow outdoors: Mar 19 to Apr 30Plant for fall: Sep 6 to Sep 27
Start indoors: Mar 26 to Apr 2Transplant outside: May 7 to May 14Sow outdoors: Apr 30 to May 14Plant for fall: Aug 2 to Aug 16
Start indoors: Mar 26 to Apr 2Sow outdoors: Apr 30 to May 14Plant for fall: Aug 9 to Aug 23
Start indoors: Mar 26 to Apr 2Sow outdoors: Apr 30 to May 14
Start indoors: Mar 26 to Apr 2Transplant outside: May 7 to May 21
Sow outdoors: Apr 2 to Apr 30Plant for fall: Jul 26 to Aug 9
Sow outdoors: Apr 2 to Apr 30Plant for fall: Aug 9 to Aug 23
Sow outdoors: Apr 2 to Apr 23
Sow outdoors: Apr 9 to May 7Plant for fall: Aug 9 to Aug 23
Sow outdoors: Apr 9 to Apr 30Plant for fall: Aug 23 to Sep 13
Sow outdoors: Apr 30 to May 21Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 30 to May 14
Transplant outside: May 7 to May 28
Plant for fall: Oct 4 to Nov 8
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Caldwell, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 29 – Feb 12 | Mar 26 – Apr 9 | — | — |
| Peppers | Feb 12 – Feb 26 | May 7 – May 21 | — | — |
| Eggplant | Feb 12 – Feb 26 | May 7 – May 21 | — | — |
| Tomatoes | Feb 26 – Mar 12 | Apr 30 – May 14 | — | — |
| Lettuce | Feb 26 – Mar 12 | Apr 2 – Apr 16 | Mar 26 – Apr 30 | Aug 23 – Sep 20 |
| Kale | Feb 26 – Mar 12 | Mar 26 – Apr 9 | Mar 26 – Apr 9 | Aug 9 – Aug 30 |
| Broccoli | Feb 26 – Mar 12 | Apr 9 – Apr 23 | — | Jul 12 – Aug 2 |
| Cabbage | Feb 26 – Mar 12 | Apr 2 – Apr 16 | — | Jul 12 – Aug 2 |
| Cauliflower | Feb 26 – Mar 12 | Apr 9 – Apr 23 | — | Jul 12 – Aug 2 |
| Okra | Mar 12 – Mar 26 | May 14 – May 28 | May 14 – May 28 | — |
| Basil | Mar 12 – Mar 26 | Apr 30 – May 14 | — | — |
| Peas | — | — | Mar 12 – Apr 2 | Jul 26 – Aug 16 |
| Spinach | — | — | Mar 12 – Apr 2 | Aug 23 – Sep 13 |
| Radishes | — | — | Mar 19 – Apr 30 | Sep 6 – Sep 27 |
| Cucumbers | Mar 26 – Apr 2 | May 7 – May 14 | Apr 30 – May 14 | Aug 2 – Aug 16 |
| Zucchini & Summer Squash | Mar 26 – Apr 2 | — | Apr 30 – May 14 | Aug 9 – Aug 23 |
| Winter Squash & Pumpkins | Mar 26 – Apr 2 | — | Apr 30 – May 14 | — |
| Melons & Watermelon | Mar 26 – Apr 2 | May 7 – May 21 | — | — |
| Carrots | — | — | Apr 2 – Apr 30 | Jul 26 – Aug 9 |
| Beets | — | — | Apr 2 – Apr 30 | Aug 9 – Aug 23 |
| Potatoes | — | — | Apr 2 – Apr 23 | — |
| Swiss Chard | — | — | Apr 9 – May 7 | Aug 9 – Aug 23 |
| Cilantro | — | — | Apr 9 – Apr 30 | Aug 23 – Sep 13 |
| Green Beans | — | — | Apr 30 – May 21 | Aug 2 – Aug 16 |
| Sweet Corn | — | — | Apr 30 – May 14 | — |
| Sweet Potatoes | — | May 7 – May 28 | — | — |
| Garlic | — | — | — | Oct 4 – Nov 8 |
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 Deer Flat Dam, ID weather station, 10 km away (elevation 2,510 ft (765 m)).
ZIP codes in Caldwell: 83605 83606 83607
Frost dates near Caldwell
- Middleton Apr 29 · Oct 13
- Nampa Apr 29 · Oct 13
- Huston Apr 23 · Oct 18
- Greenleaf Apr 24 · Oct 9
- Notus Apr 27 · Oct 9
- Star Apr 29 · Oct 13
- Marsing Apr 23 · Oct 18
- Wilder Apr 24 · Oct 9
Frequently asked questions
When is the last frost in Caldwell, ID?
The median last spring frost in Caldwell, ID is April 23. 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 Caldwell, ID?
The median first fall frost is October 18, with about a 10% chance of frost before October 2.
How long is the growing season in Caldwell, ID?
About 178 days between the median last spring frost and first fall frost.
What planting zone is Caldwell, ID?
Caldwell, ID is in USDA hardiness zone 7a.