Clark Fork, ID frost dates
Last spring frostMay 9median date
First fall frostOct 8median date
Growing season152 daysfrost-free
Hardiness zone6bZone 6b
How Clark Fork compares
- In 8 years out of 10, the last spring frost in Clark Fork falls between April 24 and May 25, a 31-day window. The first fall frost falls between September 25 and October 26.
- The median last frost is 5 days earlier than the Idaho median of May 14.
- Its 152-day growing season is longer than 72% of the 244 Idaho places with a regular frost season (state median 138 days).
- The last frost is 17 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 149 nights a year at or below 32°F.
- Compared with Spokane, WA, 106 km away, the last frost here is 13 days later than there and the growing season is 20 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 9 |
| 10% (safe for tender plants) | May 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 8 |
| 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 Clark Fork, ID
Clark Fork, ID frost dates — last frost May 9, first frost Oct 8, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Feb 14 to Feb 28Transplant outside: Apr 11 to Apr 25
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Sow outdoors: Apr 11 to May 16Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 11 to Apr 25Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13Sow outdoors: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 28 to Apr 18Plant for fall: Aug 13 to Sep 3
Sow outdoors: Apr 4 to May 16Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to May 30Sow outdoors: May 16 to May 30Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 18 to May 9
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 16 to Jun 6Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 16 to May 30
Transplant outside: May 23 to Jun 13
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Clark Fork, ID
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 14 – Feb 28 | Apr 11 – Apr 25 | — | — |
| Peppers | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Eggplant | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Tomatoes | Mar 14 – Mar 28 | May 16 – May 30 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 18 – May 2 | Apr 11 – May 16 | Aug 13 – Sep 10 |
| Kale | Mar 14 – Mar 28 | Apr 11 – Apr 25 | Apr 11 – Apr 25 | Jul 30 – Aug 20 |
| Broccoli | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 14 – Mar 28 | Apr 18 – May 2 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jul 2 – Jul 23 |
| Okra | Mar 28 – Apr 11 | May 30 – Jun 13 | May 30 – Jun 13 | — |
| Basil | Mar 28 – Apr 11 | May 16 – May 30 | — | — |
| Peas | — | — | Mar 28 – Apr 18 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 28 – Apr 18 | Aug 13 – Sep 3 |
| Radishes | — | — | Apr 4 – May 16 | Aug 27 – Sep 17 |
| Cucumbers | Apr 11 – Apr 18 | May 23 – May 30 | May 16 – May 30 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 11 – Apr 18 | — | May 16 – May 30 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 11 – Apr 18 | — | May 16 – May 30 | — |
| Melons & Watermelon | Apr 11 – Apr 18 | May 23 – Jun 6 | — | — |
| Carrots | — | — | Apr 18 – May 16 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 18 – May 16 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 18 – May 9 | — |
| Swiss Chard | — | — | Apr 25 – May 23 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 25 – May 16 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 16 – Jun 6 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 16 – May 30 | — |
| Sweet Potatoes | — | May 23 – Jun 13 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Cabinet Gorge, ID weather station, 10 km away (elevation 2,172 ft (662 m)).
Frost dates near Clark Fork
- Hope May 8 · Sep 28
- Sagle May 8 · Sep 28
- Kootenai May 8 · Sep 28
- Ponderay May 8 · Sep 28
- Sandpoint May 8 · Sep 28
- Careywood May 22 · Sep 22
- Bayview May 22 · Sep 22
- Dover May 8 · Sep 28
- Cocolalla May 22 · Sep 22
- Colburn May 8 · Sep 28
Frequently asked questions
When is the last frost in Clark Fork, ID?
The median last spring frost in Clark Fork, ID is May 9. There is still about a 10% chance of frost after May 25, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Clark Fork, ID?
The median first fall frost is October 8, with about a 10% chance of frost before September 25.
How long is the growing season in Clark Fork, ID?
About 152 days between the median last spring frost and first fall frost.
What planting zone is Clark Fork, ID?
Clark Fork, ID is in USDA hardiness zone 6b.