Nampa, ID frost dates
Last spring frostApr 29median date
First fall frostOct 13median date
Growing season167 daysfrost-free
Hardiness zone7aZone 7a
How Nampa compares
- In 8 years out of 10, the last spring frost in Nampa falls between April 15 and May 18, a 33-day window. The first fall frost falls between September 29 and October 28.
- The median last frost is 15 days earlier than the Idaho median of May 14.
- Its 167-day growing season is longer than 84% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 13 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 132 nights a year at or below 32°F.
- Nampa shares its weather station with Meridian, ID, 17 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 15 |
| 50% (median) | April 29 |
| 10% (safe for tender plants) | May 18 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 29 |
| 50% (median) | October 13 |
| 90% (late) | October 28 |
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 Nampa, ID
Nampa, ID frost dates — last frost Apr 29, first frost Oct 13, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 4 to Feb 18Transplant outside: Apr 1 to Apr 15
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Feb 18 to Mar 4Transplant outside: May 13 to May 27
Start indoors: Mar 4 to Mar 18Transplant outside: May 6 to May 20
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Sow outdoors: Apr 1 to May 6Plant for fall: Aug 18 to Sep 15
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 1 to Apr 15Sow outdoors: Apr 1 to Apr 15Plant for fall: Aug 4 to Aug 25
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 7 to Jul 28
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 8 to Apr 22Plant for fall: Jul 7 to Jul 28
Start indoors: Mar 4 to Mar 18Transplant outside: Apr 15 to Apr 29Plant for fall: Jul 7 to Jul 28
Start indoors: Mar 18 to Apr 1Transplant outside: May 20 to Jun 3Sow outdoors: May 20 to Jun 3
Start indoors: Mar 18 to Apr 1Transplant outside: May 6 to May 20
Sow outdoors: Mar 18 to Apr 8Plant for fall: Jul 21 to Aug 11
Sow outdoors: Mar 18 to Apr 8Plant for fall: Aug 18 to Sep 8
Sow outdoors: Mar 25 to May 6Plant for fall: Sep 1 to Sep 22
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 28 to Aug 11
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20Plant for fall: Aug 4 to Aug 18
Start indoors: Apr 1 to Apr 8Sow outdoors: May 6 to May 20
Start indoors: Apr 1 to Apr 8Transplant outside: May 13 to May 27
Sow outdoors: Apr 8 to May 6Plant for fall: Jul 21 to Aug 4
Sow outdoors: Apr 8 to May 6Plant for fall: Aug 4 to Aug 18
Sow outdoors: Apr 8 to Apr 29
Sow outdoors: Apr 15 to May 13Plant for fall: Aug 4 to Aug 18
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 18 to Sep 8
Sow outdoors: May 6 to May 27Plant for fall: Jul 28 to Aug 11
Sow outdoors: May 6 to May 20
Transplant outside: May 13 to Jun 3
Plant for fall: Sep 29 to Nov 3
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Nampa, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 4 – Feb 18 | Apr 1 – Apr 15 | — | — |
| Peppers | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Eggplant | Feb 18 – Mar 4 | May 13 – May 27 | — | — |
| Tomatoes | Mar 4 – Mar 18 | May 6 – May 20 | — | — |
| Lettuce | Mar 4 – Mar 18 | Apr 8 – Apr 22 | Apr 1 – May 6 | Aug 18 – Sep 15 |
| Kale | Mar 4 – Mar 18 | Apr 1 – Apr 15 | Apr 1 – Apr 15 | Aug 4 – Aug 25 |
| Broccoli | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 7 – Jul 28 |
| Cabbage | Mar 4 – Mar 18 | Apr 8 – Apr 22 | — | Jul 7 – Jul 28 |
| Cauliflower | Mar 4 – Mar 18 | Apr 15 – Apr 29 | — | Jul 7 – Jul 28 |
| Okra | Mar 18 – Apr 1 | May 20 – Jun 3 | May 20 – Jun 3 | — |
| Basil | Mar 18 – Apr 1 | May 6 – May 20 | — | — |
| Peas | — | — | Mar 18 – Apr 8 | Jul 21 – Aug 11 |
| Spinach | — | — | Mar 18 – Apr 8 | Aug 18 – Sep 8 |
| Radishes | — | — | Mar 25 – May 6 | Sep 1 – Sep 22 |
| Cucumbers | Apr 1 – Apr 8 | May 13 – May 20 | May 6 – May 20 | Jul 28 – Aug 11 |
| Zucchini & Summer Squash | Apr 1 – Apr 8 | — | May 6 – May 20 | Aug 4 – Aug 18 |
| Winter Squash & Pumpkins | Apr 1 – Apr 8 | — | May 6 – May 20 | — |
| Melons & Watermelon | Apr 1 – Apr 8 | May 13 – May 27 | — | — |
| Carrots | — | — | Apr 8 – May 6 | Jul 21 – Aug 4 |
| Beets | — | — | Apr 8 – May 6 | Aug 4 – Aug 18 |
| Potatoes | — | — | Apr 8 – Apr 29 | — |
| Swiss Chard | — | — | Apr 15 – May 13 | Aug 4 – Aug 18 |
| Cilantro | — | — | Apr 15 – May 6 | Aug 18 – Sep 8 |
| Green Beans | — | — | May 6 – May 27 | Jul 28 – Aug 11 |
| Sweet Corn | — | — | May 6 – May 20 | — |
| Sweet Potatoes | — | May 13 – Jun 3 | — | — |
| Garlic | — | — | — | Sep 29 – Nov 3 |
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 Nampa Sugar Factory, ID weather station, 3 km away (elevation 2,470 ft (753 m)).
ZIP codes in Nampa: 83651 83652 83653 83686 83687
Frost dates near Nampa
- Middleton Apr 29 · Oct 13
- Caldwell Apr 23 · Oct 18
- Star Apr 29 · Oct 13
- Huston Apr 23 · Oct 18
- Meridian Apr 29 · Oct 13
- Marsing Apr 23 · Oct 18
- Greenleaf Apr 24 · Oct 9
- Notus Apr 27 · Oct 9
- Kuna Apr 24 · Oct 21
- Eagle May 17 · Oct 12
Frequently asked questions
When is the last frost in Nampa, ID?
The median last spring frost in Nampa, ID is April 29. 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 Nampa, ID?
The median first fall frost is October 13, with about a 10% chance of frost before September 29.
How long is the growing season in Nampa, ID?
About 167 days between the median last spring frost and first fall frost.
What planting zone is Nampa, ID?
Nampa, ID is in USDA hardiness zone 7a.