Preston, ID frost dates
Last spring frostMay 16median date
First fall frostSep 28median date
Growing season135 daysfrost-free
Hardiness zone6aZone 6a
How Preston compares
- In 8 years out of 10, the last spring frost in Preston falls between May 2 and June 4, a 33-day window. The first fall frost falls between September 14 and October 14.
- The median last frost is 2 days later than the Idaho median of May 14.
- Its 135-day growing season is longer than 42% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 17 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 175 nights a year at or below 32°F.
- Compared with Logan, UT, 43 km away, the last frost here is 8 days later than there and the growing season is 12 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 2 |
| 50% (median) | May 16 |
| 10% (safe for tender plants) | June 4 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 14 |
| 50% (median) | September 28 |
| 90% (late) | October 14 |
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 Preston, ID
Preston, ID frost dates — last frost May 16, first frost Sep 28, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 21 to Mar 7Transplant outside: Apr 18 to May 2
Start indoors: Mar 7 to Mar 21Transplant outside: May 30 to Jun 13
Start indoors: Mar 7 to Mar 21Transplant outside: May 30 to Jun 13
Start indoors: Mar 21 to Apr 4Transplant outside: May 23 to Jun 6
Start indoors: Mar 21 to Apr 4Transplant outside: Apr 25 to May 9Sow outdoors: Apr 18 to May 23Plant for fall: Aug 3 to Aug 31
Start indoors: Mar 21 to Apr 4Transplant outside: Apr 18 to May 2Sow outdoors: Apr 18 to May 2Plant for fall: Jul 20 to Aug 10
Start indoors: Mar 21 to Apr 4Transplant outside: May 2 to May 16Plant for fall: Jun 22 to Jul 13
Start indoors: Mar 21 to Apr 4Transplant outside: Apr 25 to May 9Plant for fall: Jun 22 to Jul 13
Start indoors: Mar 21 to Apr 4Transplant outside: May 2 to May 16Plant for fall: Jun 22 to Jul 13
Start indoors: Apr 4 to Apr 18Transplant outside: Jun 6 to Jun 20Sow outdoors: Jun 6 to Jun 20
Start indoors: Apr 4 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 4 to Apr 25Plant for fall: Jul 6 to Jul 27
Sow outdoors: Apr 4 to Apr 25Plant for fall: Aug 3 to Aug 24
Sow outdoors: Apr 11 to May 23Plant for fall: Aug 17 to Sep 7
Start indoors: Apr 18 to Apr 25Transplant outside: May 30 to Jun 6Sow outdoors: May 23 to Jun 6Plant for fall: Jul 13 to Jul 27
Start indoors: Apr 18 to Apr 25Sow outdoors: May 23 to Jun 6Plant for fall: Jul 20 to Aug 3
Start indoors: Apr 18 to Apr 25Sow outdoors: May 23 to Jun 6
Start indoors: Apr 18 to Apr 25Transplant outside: May 30 to Jun 13
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 6 to Jul 20
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 20 to Aug 3
Sow outdoors: Apr 25 to May 16
Sow outdoors: May 2 to May 30Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 2 to May 23Plant for fall: Aug 3 to Aug 24
Sow outdoors: May 23 to Jun 13Plant for fall: Jul 13 to Jul 27
Sow outdoors: May 23 to Jun 6
Transplant outside: May 30 to Jun 20
Plant for fall: Sep 14 to Oct 19
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Preston, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 21 – Mar 7 | Apr 18 – May 2 | — | — |
| Peppers | Mar 7 – Mar 21 | May 30 – Jun 13 | — | — |
| Eggplant | Mar 7 – Mar 21 | May 30 – Jun 13 | — | — |
| Tomatoes | Mar 21 – Apr 4 | May 23 – Jun 6 | — | — |
| Lettuce | Mar 21 – Apr 4 | Apr 25 – May 9 | Apr 18 – May 23 | Aug 3 – Aug 31 |
| Kale | Mar 21 – Apr 4 | Apr 18 – May 2 | Apr 18 – May 2 | Jul 20 – Aug 10 |
| Broccoli | Mar 21 – Apr 4 | May 2 – May 16 | — | Jun 22 – Jul 13 |
| Cabbage | Mar 21 – Apr 4 | Apr 25 – May 9 | — | Jun 22 – Jul 13 |
| Cauliflower | Mar 21 – Apr 4 | May 2 – May 16 | — | Jun 22 – Jul 13 |
| Okra | Apr 4 – Apr 18 | Jun 6 – Jun 20 | Jun 6 – Jun 20 | — |
| Basil | Apr 4 – Apr 18 | May 23 – Jun 6 | — | — |
| Peas | — | — | Apr 4 – Apr 25 | Jul 6 – Jul 27 |
| Spinach | — | — | Apr 4 – Apr 25 | Aug 3 – Aug 24 |
| Radishes | — | — | Apr 11 – May 23 | Aug 17 – Sep 7 |
| Cucumbers | Apr 18 – Apr 25 | May 30 – Jun 6 | May 23 – Jun 6 | Jul 13 – Jul 27 |
| Zucchini & Summer Squash | Apr 18 – Apr 25 | — | May 23 – Jun 6 | Jul 20 – Aug 3 |
| Winter Squash & Pumpkins | Apr 18 – Apr 25 | — | May 23 – Jun 6 | — |
| Melons & Watermelon | Apr 18 – Apr 25 | May 30 – Jun 13 | — | — |
| Carrots | — | — | Apr 25 – May 23 | Jul 6 – Jul 20 |
| Beets | — | — | Apr 25 – May 23 | Jul 20 – Aug 3 |
| Potatoes | — | — | Apr 25 – May 16 | — |
| Swiss Chard | — | — | May 2 – May 30 | Jul 20 – Aug 3 |
| Cilantro | — | — | May 2 – May 23 | Aug 3 – Aug 24 |
| Green Beans | — | — | May 23 – Jun 13 | Jul 13 – Jul 27 |
| Sweet Corn | — | — | May 23 – Jun 6 | — |
| Sweet Potatoes | — | May 30 – Jun 20 | — | — |
| Garlic | — | — | — | Sep 14 – Oct 19 |
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 Preston, ID weather station, 3 km away (elevation 4,718 ft (1,438 m)).
Frost dates near Preston
- Franklin May 16 · Sep 28
- Dayton May 16 · Sep 28
- Weston May 16 · Sep 28
- Clifton May 16 · Sep 28
- Swanlake May 31 · Sep 18
- Thatcher May 29 · Sep 17
- Fish Haven May 15 · Oct 4
- Malad City May 22 · Sep 20
- Bloomington May 19 · Sep 21
- Paris Jun 17 · Sep 3
Frequently asked questions
When is the last frost in Preston, ID?
The median last spring frost in Preston, ID is May 16. There is still about a 10% chance of frost after June 4, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Preston, ID?
The median first fall frost is September 28, with about a 10% chance of frost before September 14.
How long is the growing season in Preston, ID?
About 135 days between the median last spring frost and first fall frost.
What planting zone is Preston, ID?
Preston, ID is in USDA hardiness zone 6a.