Monmouth, OR frost dates
Last spring frostApr 16median date
First fall frostNov 1median date
Growing season199 daysfrost-free
Hardiness zone8bZone 8b
How Monmouth compares
- In 8 years out of 10, the last spring frost in Monmouth falls between March 21 and May 5, a 45-day window. The first fall frost falls between October 13 and November 22.
- The median last frost is the same as the Oregon median of Apr 16.
- Its 199-day growing season is longer than 54% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 31 days later than the zone 8b median of Mar 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 8b chart.
- The weather station records an average of 49 nights a year at or below 32°F.
- Compared with Salem, OR, 22 km away, the last frost here is 13 days later than there and the growing season is 13 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 21 |
| 50% (median) | April 16 |
| 10% (safe for tender plants) | May 5 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 13 |
| 50% (median) | November 1 |
| 90% (late) | November 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 Monmouth, OR
Monmouth, OR frost dates — last frost Apr 16, first frost Nov 1, zone 8b. whenisthelastfrost.com
Crop
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Start indoors: Jan 22 to Feb 5Transplant outside: Mar 19 to Apr 2
Start indoors: Feb 5 to Feb 19Transplant outside: Apr 30 to May 14
Start indoors: Feb 5 to Feb 19Transplant outside: Apr 30 to May 14
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 23 to May 7
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 26 to Apr 9Sow outdoors: Mar 19 to Apr 23Plant for fall: Sep 6 to Oct 4
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 19 to Apr 2Sow outdoors: Mar 19 to Apr 2Plant for fall: Aug 23 to Sep 13
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 2 to Apr 16Plant for fall: Jul 26 to Aug 16
Start indoors: Feb 19 to Mar 5Transplant outside: Mar 26 to Apr 9Plant for fall: Jul 26 to Aug 16
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 2 to Apr 16Plant for fall: Jul 26 to Aug 16
Start indoors: Mar 5 to Mar 19Transplant outside: May 7 to May 21Sow outdoors: May 7 to May 21
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 23 to May 7
Sow outdoors: Mar 5 to Mar 26Plant for fall: Aug 9 to Aug 30
Sow outdoors: Mar 5 to Mar 26Plant for fall: Sep 6 to Sep 27
Sow outdoors: Mar 12 to Apr 23Plant for fall: Sep 20 to Oct 11
Start indoors: Mar 19 to Mar 26Transplant outside: Apr 30 to May 7Sow outdoors: Apr 23 to May 7Plant for fall: Aug 16 to Aug 30
Start indoors: Mar 19 to Mar 26Sow outdoors: Apr 23 to May 7Plant for fall: Aug 23 to Sep 6
Start indoors: Mar 19 to Mar 26Sow outdoors: Apr 23 to May 7
Start indoors: Mar 19 to Mar 26Transplant outside: Apr 30 to May 14
Sow outdoors: Mar 26 to Apr 23Plant for fall: Aug 9 to Aug 23
Sow outdoors: Mar 26 to Apr 23Plant for fall: Aug 23 to Sep 6
Sow outdoors: Mar 26 to Apr 16
Sow outdoors: Apr 2 to Apr 30Plant for fall: Aug 23 to Sep 6
Sow outdoors: Apr 2 to Apr 23Plant for fall: Sep 6 to Sep 27
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 16 to Aug 30
Sow outdoors: Apr 23 to May 7
Transplant outside: Apr 30 to May 21
Plant for fall: Oct 18 to Nov 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Monmouth, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 22 – Feb 5 | Mar 19 – Apr 2 | — | — |
| Peppers | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Eggplant | Feb 5 – Feb 19 | Apr 30 – May 14 | — | — |
| Tomatoes | Feb 19 – Mar 5 | Apr 23 – May 7 | — | — |
| Lettuce | Feb 19 – Mar 5 | Mar 26 – Apr 9 | Mar 19 – Apr 23 | Sep 6 – Oct 4 |
| Kale | Feb 19 – Mar 5 | Mar 19 – Apr 2 | Mar 19 – Apr 2 | Aug 23 – Sep 13 |
| Broccoli | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 26 – Aug 16 |
| Cabbage | Feb 19 – Mar 5 | Mar 26 – Apr 9 | — | Jul 26 – Aug 16 |
| Cauliflower | Feb 19 – Mar 5 | Apr 2 – Apr 16 | — | Jul 26 – Aug 16 |
| Okra | Mar 5 – Mar 19 | May 7 – May 21 | May 7 – May 21 | — |
| Basil | Mar 5 – Mar 19 | Apr 23 – May 7 | — | — |
| Peas | — | — | Mar 5 – Mar 26 | Aug 9 – Aug 30 |
| Spinach | — | — | Mar 5 – Mar 26 | Sep 6 – Sep 27 |
| Radishes | — | — | Mar 12 – Apr 23 | Sep 20 – Oct 11 |
| Cucumbers | Mar 19 – Mar 26 | Apr 30 – May 7 | Apr 23 – May 7 | Aug 16 – Aug 30 |
| Zucchini & Summer Squash | Mar 19 – Mar 26 | — | Apr 23 – May 7 | Aug 23 – Sep 6 |
| Winter Squash & Pumpkins | Mar 19 – Mar 26 | — | Apr 23 – May 7 | — |
| Melons & Watermelon | Mar 19 – Mar 26 | Apr 30 – May 14 | — | — |
| Carrots | — | — | Mar 26 – Apr 23 | Aug 9 – Aug 23 |
| Beets | — | — | Mar 26 – Apr 23 | Aug 23 – Sep 6 |
| Potatoes | — | — | Mar 26 – Apr 16 | — |
| Swiss Chard | — | — | Apr 2 – Apr 30 | Aug 23 – Sep 6 |
| Cilantro | — | — | Apr 2 – Apr 23 | Sep 6 – Sep 27 |
| Green Beans | — | — | Apr 23 – May 14 | Aug 16 – Aug 30 |
| Sweet Corn | — | — | Apr 23 – May 7 | — |
| Sweet Potatoes | — | Apr 30 – May 21 | — | — |
| Garlic | — | — | — | Oct 18 – Nov 22 |
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 Dallas 2 Ne, OR weather station, 12 km away (elevation 289 ft (88 m)).
Frost dates near Monmouth
- Independence Apr 16 · Nov 1
- Dallas Apr 16 · Nov 1
- Falls City Apr 18 · Nov 7
- Rickreall Apr 16 · Nov 1
- Jefferson Mar 29 · Nov 6
- Salem Apr 3 · Nov 1
- Turner Apr 3 · Nov 1
- Keizer Apr 3 · Nov 1
- Albany Apr 17 · Oct 28
- Sheridan Apr 16 · Nov 1
Frequently asked questions
When is the last frost in Monmouth, OR?
The median last spring frost in Monmouth, OR is April 16. There is still about a 10% chance of frost after May 5, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Monmouth, OR?
The median first fall frost is November 1, with about a 10% chance of frost before October 13.
How long is the growing season in Monmouth, OR?
About 199 days between the median last spring frost and first fall frost.
What planting zone is Monmouth, OR?
Monmouth, OR is in USDA hardiness zone 8b.