Imnaha, OR frost dates
Last spring frostJun 8median date
First fall frostSep 5median date
Growing season89 daysfrost-free
Hardiness zone6bZone 6b
How Imnaha compares
- In 8 years out of 10, the last spring frost in Imnaha falls between May 18 and July 8, a 51-day window. The first fall frost falls between August 16 and September 22.
- The median last frost is 53 days later than the Oregon median of Apr 16.
- Its 89-day growing season is among the shortest of the 345 Oregon places with a regular frost season.
- The last frost is 47 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 204 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 18 |
| 50% (median) | June 8 |
| 10% (safe for tender plants) | July 8 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 16 |
| 50% (median) | September 5 |
| 90% (late) | September 22 |
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 Imnaha, OR
Imnaha, OR frost dates — last frost Jun 8, first frost Sep 5, zone 6b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 16 to Mar 30Transplant outside: May 11 to May 25
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 22 to Jul 6
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 22 to Jul 6
Start indoors: Apr 13 to Apr 27Transplant outside: Jun 15 to Jun 29
Start indoors: Apr 13 to Apr 27Transplant outside: May 18 to Jun 1Sow outdoors: May 11 to Jun 15Plant for fall: Jul 11 to Aug 8
Start indoors: Apr 13 to Apr 27Transplant outside: May 11 to May 25Sow outdoors: May 11 to May 25Plant for fall: Jun 27 to Jul 18
Start indoors: Apr 13 to Apr 27Transplant outside: May 25 to Jun 8
Start indoors: Apr 13 to Apr 27Transplant outside: May 18 to Jun 1
Start indoors: Apr 13 to Apr 27Transplant outside: May 25 to Jun 8
Start indoors: Apr 27 to May 11Transplant outside: Jun 29 to Jul 13Sow outdoors: Jun 29 to Jul 13
Start indoors: Apr 27 to May 11Transplant outside: Jun 15 to Jun 29
Sow outdoors: Apr 27 to May 18
Sow outdoors: Apr 27 to May 18Plant for fall: Jul 11 to Aug 1
Sow outdoors: May 4 to Jun 15Plant for fall: Jul 25 to Aug 15
Start indoors: May 11 to May 18Transplant outside: Jun 22 to Jun 29Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Sow outdoors: Jun 15 to Jun 29
Start indoors: May 11 to May 18Transplant outside: Jun 22 to Jul 6
Sow outdoors: May 18 to Jun 15
Sow outdoors: May 18 to Jun 15
Sow outdoors: May 18 to Jun 8
Sow outdoors: May 25 to Jun 22
Sow outdoors: May 25 to Jun 15Plant for fall: Jul 11 to Aug 1
Sow outdoors: Jun 15 to Jul 6
Sow outdoors: Jun 15 to Jun 29
Transplant outside: Jun 22 to Jul 13
Plant for fall: Aug 22 to Sep 26
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Imnaha, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 16 – Mar 30 | May 11 – May 25 | — | — |
| Peppers | Mar 30 – Apr 13 | Jun 22 – Jul 6 | — | — |
| Eggplant | Mar 30 – Apr 13 | Jun 22 – Jul 6 | — | — |
| Tomatoes | Apr 13 – Apr 27 | Jun 15 – Jun 29 | — | — |
| Lettuce | Apr 13 – Apr 27 | May 18 – Jun 1 | May 11 – Jun 15 | Jul 11 – Aug 8 |
| Kale | Apr 13 – Apr 27 | May 11 – May 25 | May 11 – May 25 | Jun 27 – Jul 18 |
| Broccoli | Apr 13 – Apr 27 | May 25 – Jun 8 | — | — |
| Cabbage | Apr 13 – Apr 27 | May 18 – Jun 1 | — | — |
| Cauliflower | Apr 13 – Apr 27 | May 25 – Jun 8 | — | — |
| Okra | Apr 27 – May 11 | Jun 29 – Jul 13 | Jun 29 – Jul 13 | — |
| Basil | Apr 27 – May 11 | Jun 15 – Jun 29 | — | — |
| Peas | — | — | Apr 27 – May 18 | — |
| Spinach | — | — | Apr 27 – May 18 | Jul 11 – Aug 1 |
| Radishes | — | — | May 4 – Jun 15 | Jul 25 – Aug 15 |
| Cucumbers | May 11 – May 18 | Jun 22 – Jun 29 | Jun 15 – Jun 29 | — |
| Zucchini & Summer Squash | May 11 – May 18 | — | Jun 15 – Jun 29 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 89 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 11 – May 18 | — | Jun 15 – Jun 29 | — |
| Melons & Watermelon Warning: Your frost-free season is about 89 days, which is tight for melons & watermelon (85+ days). Choose early varieties and use transplants or row covers. | May 11 – May 18 | Jun 22 – Jul 6 | — | — |
| Carrots | — | — | May 18 – Jun 15 | — |
| Beets | — | — | May 18 – Jun 15 | — |
| Potatoes | — | — | May 18 – Jun 8 | — |
| Swiss Chard | — | — | May 25 – Jun 22 | — |
| Cilantro | — | — | May 25 – Jun 15 | Jul 11 – Aug 1 |
| Green Beans | — | — | Jun 15 – Jul 6 | — |
| Sweet Corn Warning: Your frost-free season is about 89 days, which is tight for sweet corn (80+ days). Choose early varieties and use transplants or row covers. | — | — | Jun 15 – Jun 29 | — |
| Sweet Potatoes Warning: Your frost-free season is about 89 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 22 – Jul 13 | — | — |
| Garlic | — | — | — | Aug 22 – Sep 26 |
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 Enterprise 20 Nne, OR weather station, 33 km away (elevation 3,281 ft (1,000 m)).
Frost dates near Imnaha
- Joseph May 24 · Oct 1
- Enterprise May 24 · Oct 1
- Lostine Jun 7 · Sep 9
- Wallowa Jun 7 · Sep 9
- Oxbow Apr 2 · Nov 5
- Halfway May 15 · Sep 24
- Cove May 11 · Sep 26
- Elgin May 24 · Sep 18
- Union May 11 · Sep 26
- Richland May 10 · Oct 1
Frequently asked questions
When is the last frost in Imnaha, OR?
The median last spring frost in Imnaha, OR is June 8. There is still about a 10% chance of frost after July 8, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Imnaha, OR?
The median first fall frost is September 5, with about a 10% chance of frost before August 16.
How long is the growing season in Imnaha, OR?
About 89 days between the median last spring frost and first fall frost.
What planting zone is Imnaha, OR?
Imnaha, OR is in USDA hardiness zone 6b.