Winchester, ID frost dates
Last spring frostMay 23median date
First fall frostSep 25median date
Growing season125 daysfrost-free
Hardiness zone6bZone 6b
How Winchester compares
- In 8 years out of 10, the last spring frost in Winchester falls between May 4 and June 19, a 46-day window. The first fall frost falls between September 7 and October 10.
- The median last frost is 9 days later than the Idaho median of May 14.
- Its 125-day growing season is longer than 29% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 31 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 171 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 4 |
| 50% (median) | May 23 |
| 10% (safe for tender plants) | June 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 7 |
| 50% (median) | September 25 |
| 90% (late) | October 10 |
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 Winchester, ID
Winchester, ID frost dates — last frost May 23, first frost Sep 25, zone 6b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 25 to May 9
Start indoors: Mar 14 to Mar 28Transplant outside: Jun 6 to Jun 20
Start indoors: Mar 14 to Mar 28Transplant outside: Jun 6 to Jun 20
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 2 to May 16Sow outdoors: Apr 25 to May 30Plant for fall: Jul 31 to Aug 28
Start indoors: Mar 28 to Apr 11Transplant outside: Apr 25 to May 9Sow outdoors: Apr 25 to May 9Plant for fall: Jul 17 to Aug 7
Start indoors: Mar 28 to Apr 11Transplant outside: May 9 to May 23Plant for fall: Jun 19 to Jul 10
Start indoors: Mar 28 to Apr 11Transplant outside: May 2 to May 16Plant for fall: Jun 19 to Jul 10
Start indoors: Mar 28 to Apr 11Transplant outside: May 9 to May 23Plant for fall: Jun 19 to Jul 10
Start indoors: Apr 11 to Apr 25Transplant outside: Jun 13 to Jun 27Sow outdoors: Jun 13 to Jun 27
Start indoors: Apr 11 to Apr 25Transplant outside: May 30 to Jun 13
Sow outdoors: Apr 11 to May 2Plant for fall: Jul 3 to Jul 24
Sow outdoors: Apr 11 to May 2Plant for fall: Jul 31 to Aug 21
Sow outdoors: Apr 18 to May 30Plant for fall: Aug 14 to Sep 4
Start indoors: Apr 25 to May 2Transplant outside: Jun 6 to Jun 13Sow outdoors: May 30 to Jun 13Plant for fall: Jul 10 to Jul 24
Start indoors: Apr 25 to May 2Sow outdoors: May 30 to Jun 13Plant for fall: Jul 17 to Jul 31
Start indoors: Apr 25 to May 2Sow outdoors: May 30 to Jun 13
Start indoors: Apr 25 to May 2Transplant outside: Jun 6 to Jun 20
Sow outdoors: May 2 to May 30Plant for fall: Jul 3 to Jul 17
Sow outdoors: May 2 to May 30Plant for fall: Jul 17 to Jul 31
Sow outdoors: May 2 to May 23
Sow outdoors: May 9 to Jun 6Plant for fall: Jul 17 to Jul 31
Sow outdoors: May 9 to May 30Plant for fall: Jul 31 to Aug 21
Sow outdoors: May 30 to Jun 20Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 30 to Jun 13
Transplant outside: Jun 6 to Jun 27
Plant for fall: Sep 11 to Oct 16
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Winchester, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 28 – Mar 14 | Apr 25 – May 9 | — | — |
| Peppers | Mar 14 – Mar 28 | Jun 6 – Jun 20 | — | — |
| Eggplant | Mar 14 – Mar 28 | Jun 6 – Jun 20 | — | — |
| Tomatoes | Mar 28 – Apr 11 | May 30 – Jun 13 | — | — |
| Lettuce | Mar 28 – Apr 11 | May 2 – May 16 | Apr 25 – May 30 | Jul 31 – Aug 28 |
| Kale | Mar 28 – Apr 11 | Apr 25 – May 9 | Apr 25 – May 9 | Jul 17 – Aug 7 |
| Broccoli | Mar 28 – Apr 11 | May 9 – May 23 | — | Jun 19 – Jul 10 |
| Cabbage | Mar 28 – Apr 11 | May 2 – May 16 | — | Jun 19 – Jul 10 |
| Cauliflower | Mar 28 – Apr 11 | May 9 – May 23 | — | Jun 19 – Jul 10 |
| Okra | Apr 11 – Apr 25 | Jun 13 – Jun 27 | Jun 13 – Jun 27 | — |
| Basil | Apr 11 – Apr 25 | May 30 – Jun 13 | — | — |
| Peas | — | — | Apr 11 – May 2 | Jul 3 – Jul 24 |
| Spinach | — | — | Apr 11 – May 2 | Jul 31 – Aug 21 |
| Radishes | — | — | Apr 18 – May 30 | Aug 14 – Sep 4 |
| Cucumbers | Apr 25 – May 2 | Jun 6 – Jun 13 | May 30 – Jun 13 | Jul 10 – Jul 24 |
| Zucchini & Summer Squash | Apr 25 – May 2 | — | May 30 – Jun 13 | Jul 17 – Jul 31 |
| Winter Squash & Pumpkins | Apr 25 – May 2 | — | May 30 – Jun 13 | — |
| Melons & Watermelon | Apr 25 – May 2 | Jun 6 – Jun 20 | — | — |
| Carrots | — | — | May 2 – May 30 | Jul 3 – Jul 17 |
| Beets | — | — | May 2 – May 30 | Jul 17 – Jul 31 |
| Potatoes | — | — | May 2 – May 23 | — |
| Swiss Chard | — | — | May 9 – Jun 6 | Jul 17 – Jul 31 |
| Cilantro | — | — | May 9 – May 30 | Jul 31 – Aug 21 |
| Green Beans | — | — | May 30 – Jun 20 | Jul 10 – Jul 24 |
| Sweet Corn | — | — | May 30 – Jun 13 | — |
| Sweet Potatoes | — | Jun 6 – Jun 27 | — | — |
| Garlic | — | — | — | Sep 11 – Oct 16 |
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 Winchester, ID weather station, about 1 km away (elevation 3,973 ft (1,211 m)).
Frost dates near Winchester
- Craigmont May 23 · Sep 25
- Reubens May 23 · Sep 25
- Culdesac May 23 · Sep 25
- Ferdinand May 6 · Oct 13
- Lewiston Apr 6 · Oct 26
- Lapwai Apr 6 · Oct 26
- Cottonwood May 6 · Oct 13
- Nezperce May 24 · Sep 20
- Greencreek May 6 · Oct 13
- Peck Apr 20 · Oct 20
Frequently asked questions
When is the last frost in Winchester, ID?
The median last spring frost in Winchester, ID is May 23. There is still about a 10% chance of frost after June 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Winchester, ID?
The median first fall frost is September 25, with about a 10% chance of frost before September 7.
How long is the growing season in Winchester, ID?
About 125 days between the median last spring frost and first fall frost.
What planting zone is Winchester, ID?
Winchester, ID is in USDA hardiness zone 6b.