Princeton, OR frost dates
Last spring frostMay 29median date
First fall frostSep 18median date
Growing season112 daysfrost-free
Hardiness zone6bZone 6b
How Princeton compares
- In 8 years out of 10, the last spring frost in Princeton falls between May 6 and June 17, a 42-day window. The first fall frost falls between September 2 and October 3.
- The median last frost is 43 days later than the Oregon median of Apr 16.
- Its 112-day growing season is longer than 9% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 37 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 184 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 6 |
| 50% (median) | May 29 |
| 10% (safe for tender plants) | June 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 2 |
| 50% (median) | September 18 |
| 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 Princeton, OR
Princeton, OR frost dates — last frost May 29, first frost Sep 18, zone 6b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 6 to Mar 20Transplant outside: May 1 to May 15
Start indoors: Mar 20 to Apr 3Transplant outside: Jun 12 to Jun 26
Start indoors: Mar 20 to Apr 3Transplant outside: Jun 12 to Jun 26
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 8 to May 22Sow outdoors: May 1 to Jun 5Plant for fall: Jul 24 to Aug 21
Start indoors: Apr 3 to Apr 17Transplant outside: May 1 to May 15Sow outdoors: May 1 to May 15Plant for fall: Jul 10 to Jul 31
Start indoors: Apr 3 to Apr 17Transplant outside: May 15 to May 29
Start indoors: Apr 3 to Apr 17Transplant outside: May 8 to May 22
Start indoors: Apr 3 to Apr 17Transplant outside: May 15 to May 29
Start indoors: Apr 17 to May 1Transplant outside: Jun 19 to Jul 3Sow outdoors: Jun 19 to Jul 3
Start indoors: Apr 17 to May 1Transplant outside: Jun 5 to Jun 19
Sow outdoors: Apr 17 to May 8Plant for fall: Jun 26 to Jul 17
Sow outdoors: Apr 17 to May 8Plant for fall: Jul 24 to Aug 14
Sow outdoors: Apr 24 to Jun 5Plant for fall: Aug 7 to Aug 28
Start indoors: May 1 to May 8Transplant outside: Jun 12 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: May 1 to May 8Sow outdoors: Jun 5 to Jun 19Plant for fall: Jul 10 to Jul 24
Start indoors: May 1 to May 8Sow outdoors: Jun 5 to Jun 19
Start indoors: May 1 to May 8Transplant outside: Jun 12 to Jun 26
Sow outdoors: May 8 to Jun 5Plant for fall: Jun 26 to Jul 10
Sow outdoors: May 8 to Jun 5Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 8 to May 29
Sow outdoors: May 15 to Jun 12Plant for fall: Jul 10 to Jul 24
Sow outdoors: May 15 to Jun 5Plant for fall: Jul 24 to Aug 14
Sow outdoors: Jun 5 to Jun 26
Sow outdoors: Jun 5 to Jun 19
Transplant outside: Jun 12 to Jul 3
Plant for fall: Sep 4 to Oct 9
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Princeton, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 6 – Mar 20 | May 1 – May 15 | — | — |
| Peppers | Mar 20 – Apr 3 | Jun 12 – Jun 26 | — | — |
| Eggplant | Mar 20 – Apr 3 | Jun 12 – Jun 26 | — | — |
| Tomatoes | Apr 3 – Apr 17 | Jun 5 – Jun 19 | — | — |
| Lettuce | Apr 3 – Apr 17 | May 8 – May 22 | May 1 – Jun 5 | Jul 24 – Aug 21 |
| Kale | Apr 3 – Apr 17 | May 1 – May 15 | May 1 – May 15 | Jul 10 – Jul 31 |
| Broccoli | Apr 3 – Apr 17 | May 15 – May 29 | — | — |
| Cabbage | Apr 3 – Apr 17 | May 8 – May 22 | — | — |
| Cauliflower | Apr 3 – Apr 17 | May 15 – May 29 | — | — |
| Okra | Apr 17 – May 1 | Jun 19 – Jul 3 | Jun 19 – Jul 3 | — |
| Basil | Apr 17 – May 1 | Jun 5 – Jun 19 | — | — |
| Peas | — | — | Apr 17 – May 8 | Jun 26 – Jul 17 |
| Spinach | — | — | Apr 17 – May 8 | Jul 24 – Aug 14 |
| Radishes | — | — | Apr 24 – Jun 5 | Aug 7 – Aug 28 |
| Cucumbers | May 1 – May 8 | Jun 12 – Jun 19 | Jun 5 – Jun 19 | — |
| Zucchini & Summer Squash | May 1 – May 8 | — | Jun 5 – Jun 19 | Jul 10 – Jul 24 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 112 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 1 – May 8 | — | Jun 5 – Jun 19 | — |
| Melons & Watermelon | May 1 – May 8 | Jun 12 – Jun 26 | — | — |
| Carrots | — | — | May 8 – Jun 5 | Jun 26 – Jul 10 |
| Beets | — | — | May 8 – Jun 5 | Jul 10 – Jul 24 |
| Potatoes | — | — | May 8 – May 29 | — |
| Swiss Chard | — | — | May 15 – Jun 12 | Jul 10 – Jul 24 |
| Cilantro | — | — | May 15 – Jun 5 | Jul 24 – Aug 14 |
| Green Beans | — | — | Jun 5 – Jun 26 | — |
| Sweet Corn | — | — | Jun 5 – Jun 19 | — |
| Sweet Potatoes Warning: Your frost-free season is about 112 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 12 – Jul 3 | — | — |
| Garlic | — | — | — | Sep 4 – Oct 9 |
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 Malheur Refuge Hq, OR weather station, 33 km away (elevation 4,117 ft (1,255 m)).
Frost dates near Princeton
- Diamond May 29 · Sep 18
- Frenchglen frost any month
- Burns Jun 11 · Sep 6
- Hines Jun 11 · Sep 6
- Crane Jun 7 · Sep 6
- Riley Jun 11 · Sep 28
- Plush frost any month
- Riverside Jun 7 · Sep 6
- Fields May 10 · Oct 7
- Drewsey Jun 5 · Sep 5
Frequently asked questions
When is the last frost in Princeton, OR?
The median last spring frost in Princeton, OR is May 29. There is still about a 10% chance of frost after June 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Princeton, OR?
The median first fall frost is September 18, with about a 10% chance of frost before September 2.
How long is the growing season in Princeton, OR?
About 112 days between the median last spring frost and first fall frost.
What planting zone is Princeton, OR?
Princeton, OR is in USDA hardiness zone 6b.