Frost dates for 83606 — Caldwell, ID
Last spring frostApr 27median date
First fall frostOct 9median date
Growing season165 daysfrost-free
Hardiness zone7aZone 7a
How Caldwell compares
- In 8 years out of 10, the last spring frost in Caldwell falls between April 13 and May 9, a 26-day window. The first fall frost falls between September 26 and October 26.
- The median last frost is 17 days earlier than the Idaho median of May 14.
- Its 165-day growing season is longer than 83% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 11 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 144 nights a year at or below 32°F.
- Compared with Nampa, ID, 20 km away, the last frost here is 2 days earlier than there and the growing season is 2 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 13 |
| 50% (median) | April 27 |
| 10% (safe for tender plants) | May 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 26 |
| 50% (median) | October 9 |
| 90% (late) | October 26 |
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 83606 — Caldwell, ID — last frost Apr 27, first frost Oct 9, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 2 to Feb 16Transplant outside: Mar 30 to Apr 13
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Mar 2 to Mar 16Transplant outside: May 4 to May 18
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Sow outdoors: Mar 30 to May 4Plant for fall: Aug 14 to Sep 11
Start indoors: Mar 2 to Mar 16Transplant outside: Mar 30 to Apr 13Sow outdoors: Mar 30 to Apr 13Plant for fall: Jul 31 to Aug 21
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1Sow outdoors: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: May 4 to May 18
Sow outdoors: Mar 16 to Apr 6Plant for fall: Jul 17 to Aug 7
Sow outdoors: Mar 16 to Apr 6Plant for fall: Aug 14 to Sep 4
Sow outdoors: Mar 23 to May 4Plant for fall: Aug 28 to Sep 18
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 18Sow outdoors: May 4 to May 18Plant for fall: Jul 24 to Aug 7
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18Plant for fall: Jul 31 to Aug 14
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Apr 6 to May 4Plant for fall: Jul 17 to Jul 31
Sow outdoors: Apr 6 to May 4Plant for fall: Jul 31 to Aug 14
Sow outdoors: Apr 6 to Apr 27
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 31 to Aug 14
Sow outdoors: Apr 13 to May 4Plant for fall: Aug 14 to Sep 4
Sow outdoors: May 4 to May 25Plant for fall: Jul 24 to Aug 7
Sow outdoors: May 4 to May 18
Transplant outside: May 11 to Jun 1
Plant for fall: Sep 25 to Oct 30
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Caldwell, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 2 – Feb 16 | Mar 30 – Apr 13 | — | — |
| Peppers | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Eggplant | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Tomatoes | Mar 2 – Mar 16 | May 4 – May 18 | — | — |
| Lettuce | Mar 2 – Mar 16 | Apr 6 – Apr 20 | Mar 30 – May 4 | Aug 14 – Sep 11 |
| Kale | Mar 2 – Mar 16 | Mar 30 – Apr 13 | Mar 30 – Apr 13 | Jul 31 – Aug 21 |
| Broccoli | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 3 – Jul 24 |
| Cabbage | Mar 2 – Mar 16 | Apr 6 – Apr 20 | — | Jul 3 – Jul 24 |
| Cauliflower | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 3 – Jul 24 |
| Okra | Mar 16 – Mar 30 | May 18 – Jun 1 | May 18 – Jun 1 | — |
| Basil | Mar 16 – Mar 30 | May 4 – May 18 | — | — |
| Peas | — | — | Mar 16 – Apr 6 | Jul 17 – Aug 7 |
| Spinach | — | — | Mar 16 – Apr 6 | Aug 14 – Sep 4 |
| Radishes | — | — | Mar 23 – May 4 | Aug 28 – Sep 18 |
| Cucumbers | Mar 30 – Apr 6 | May 11 – May 18 | May 4 – May 18 | Jul 24 – Aug 7 |
| Zucchini & Summer Squash | Mar 30 – Apr 6 | — | May 4 – May 18 | Jul 31 – Aug 14 |
| Winter Squash & Pumpkins | Mar 30 – Apr 6 | — | May 4 – May 18 | — |
| Melons & Watermelon | Mar 30 – Apr 6 | May 11 – May 25 | — | — |
| Carrots | — | — | Apr 6 – May 4 | Jul 17 – Jul 31 |
| Beets | — | — | Apr 6 – May 4 | Jul 31 – Aug 14 |
| Potatoes | — | — | Apr 6 – Apr 27 | — |
| Swiss Chard | — | — | Apr 13 – May 11 | Jul 31 – Aug 14 |
| Cilantro | — | — | Apr 13 – May 4 | Aug 14 – Sep 4 |
| Green Beans | — | — | May 4 – May 25 | Jul 24 – Aug 7 |
| Sweet Corn | — | — | May 4 – May 18 | — |
| Sweet Potatoes | — | May 11 – Jun 1 | — | — |
| Garlic | — | — | — | Sep 25 – Oct 30 |
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 Parma Exp Stn, ID weather station, 14 km away (elevation 2,290 ft (698 m)).
ZIP codes in Caldwell: 83605 83606 83607
Frost dates near Caldwell
- Notus Apr 27 · Oct 9
- Greenleaf Apr 24 · Oct 9
- Wilder Apr 24 · Oct 9
- Parma Apr 27 · Oct 9
- Huston Apr 23 · Oct 18
- Middleton Apr 29 · Oct 13
- Homedale Apr 24 · Oct 9
- Nampa Apr 29 · Oct 13
Frequently asked questions
When is the last frost in Caldwell, ID?
The median last spring frost in Caldwell, ID is April 27. 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 9, with about a 10% chance of frost before September 26.
How long is the growing season in Caldwell, ID?
About 165 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.