Fossil, OR frost dates
Last spring frostJun 3median date
First fall frostSep 14median date
Growing season103 daysfrost-free
Hardiness zone7aZone 7a
How Fossil compares
- In 8 years out of 10, the last spring frost in Fossil falls between May 13 and July 3, a 51-day window. The first fall frost falls between August 25 and October 3.
- The median last frost is 48 days later than the Oregon median of Apr 16.
- Its 103-day growing season is longer than 6% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 48 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 127 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 13 |
| 50% (median) | June 3 |
| 10% (safe for tender plants) | July 3 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 25 |
| 50% (median) | September 14 |
| 90% (late) | October 3 |
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 Fossil, OR
Fossil, OR frost dates — last frost Jun 3, first frost Sep 14, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Mar 11 to Mar 25Transplant outside: May 6 to May 20
Start indoors: Mar 25 to Apr 8Transplant outside: Jun 17 to Jul 1
Start indoors: Mar 25 to Apr 8Transplant outside: Jun 17 to Jul 1
Start indoors: Apr 8 to Apr 22Transplant outside: Jun 10 to Jun 24
Start indoors: Apr 8 to Apr 22Transplant outside: May 13 to May 27Sow outdoors: May 6 to Jun 10Plant for fall: Jul 20 to Aug 17
Start indoors: Apr 8 to Apr 22Transplant outside: May 6 to May 20Sow outdoors: May 6 to May 20Plant for fall: Jul 6 to Jul 27
Start indoors: Apr 8 to Apr 22Transplant outside: May 20 to Jun 3
Start indoors: Apr 8 to Apr 22Transplant outside: May 13 to May 27
Start indoors: Apr 8 to Apr 22Transplant outside: May 20 to Jun 3
Start indoors: Apr 22 to May 6Transplant outside: Jun 24 to Jul 8Sow outdoors: Jun 24 to Jul 8
Start indoors: Apr 22 to May 6Transplant outside: Jun 10 to Jun 24
Sow outdoors: Apr 22 to May 13Plant for fall: Jun 22 to Jul 13
Sow outdoors: Apr 22 to May 13Plant for fall: Jul 20 to Aug 10
Sow outdoors: Apr 29 to Jun 10Plant for fall: Aug 3 to Aug 24
Start indoors: May 6 to May 13Transplant outside: Jun 17 to Jun 24Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Sow outdoors: Jun 10 to Jun 24
Start indoors: May 6 to May 13Transplant outside: Jun 17 to Jul 1
Sow outdoors: May 13 to Jun 10
Sow outdoors: May 13 to Jun 10Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 13 to Jun 3
Sow outdoors: May 20 to Jun 17Plant for fall: Jul 6 to Jul 20
Sow outdoors: May 20 to Jun 10Plant for fall: Jul 20 to Aug 10
Sow outdoors: Jun 10 to Jul 1
Sow outdoors: Jun 10 to Jun 24
Transplant outside: Jun 17 to Jul 8
Plant for fall: Aug 31 to Oct 5
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Fossil, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 11 – Mar 25 | May 6 – May 20 | — | — |
| Peppers | Mar 25 – Apr 8 | Jun 17 – Jul 1 | — | — |
| Eggplant | Mar 25 – Apr 8 | Jun 17 – Jul 1 | — | — |
| Tomatoes | Apr 8 – Apr 22 | Jun 10 – Jun 24 | — | — |
| Lettuce | Apr 8 – Apr 22 | May 13 – May 27 | May 6 – Jun 10 | Jul 20 – Aug 17 |
| Kale | Apr 8 – Apr 22 | May 6 – May 20 | May 6 – May 20 | Jul 6 – Jul 27 |
| Broccoli | Apr 8 – Apr 22 | May 20 – Jun 3 | — | — |
| Cabbage | Apr 8 – Apr 22 | May 13 – May 27 | — | — |
| Cauliflower | Apr 8 – Apr 22 | May 20 – Jun 3 | — | — |
| Okra | Apr 22 – May 6 | Jun 24 – Jul 8 | Jun 24 – Jul 8 | — |
| Basil | Apr 22 – May 6 | Jun 10 – Jun 24 | — | — |
| Peas | — | — | Apr 22 – May 13 | Jun 22 – Jul 13 |
| Spinach | — | — | Apr 22 – May 13 | Jul 20 – Aug 10 |
| Radishes | — | — | Apr 29 – Jun 10 | Aug 3 – Aug 24 |
| Cucumbers | May 6 – May 13 | Jun 17 – Jun 24 | Jun 10 – Jun 24 | — |
| Zucchini & Summer Squash | May 6 – May 13 | — | Jun 10 – Jun 24 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 103 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 6 – May 13 | — | Jun 10 – Jun 24 | — |
| Melons & Watermelon | May 6 – May 13 | Jun 17 – Jul 1 | — | — |
| Carrots | — | — | May 13 – Jun 10 | — |
| Beets | — | — | May 13 – Jun 10 | Jul 6 – Jul 20 |
| Potatoes | — | — | May 13 – Jun 3 | — |
| Swiss Chard | — | — | May 20 – Jun 17 | Jul 6 – Jul 20 |
| Cilantro | — | — | May 20 – Jun 10 | Jul 20 – Aug 10 |
| Green Beans | — | — | Jun 10 – Jul 1 | — |
| Sweet Corn | — | — | Jun 10 – Jun 24 | — |
| Sweet Potatoes Warning: Your frost-free season is about 103 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 17 – Jul 8 | — | — |
| Garlic | — | — | — | Aug 31 – Oct 5 |
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 Fossil, OR weather station, 10 km away (elevation 2,651 ft (808 m)).
Frost dates near Fossil
- Spray May 9 · Sep 27
- Condon May 10 · Oct 7
- Mitchell May 22 · Oct 4
- Kent May 15 · Oct 11
- Kimberly May 9 · Sep 27
- Shaniko May 22 · Oct 3
- Ashwood May 22 · Oct 3
- Antelope May 22 · Oct 3
- Mikkalo May 10 · Oct 7
- Monument May 9 · Sep 27
Frequently asked questions
When is the last frost in Fossil, OR?
The median last spring frost in Fossil, OR is June 3. There is still about a 10% chance of frost after July 3, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Fossil, OR?
The median first fall frost is September 14, with about a 10% chance of frost before August 25.
How long is the growing season in Fossil, OR?
About 103 days between the median last spring frost and first fall frost.
What planting zone is Fossil, OR?
Fossil, OR is in USDA hardiness zone 7a.