Monroe, OR frost dates
Last spring frostApr 11median date
First fall frostOct 30median date
Growing season202 daysfrost-free
Hardiness zone8bZone 8b
How Monroe compares
- In 8 years out of 10, the last spring frost in Monroe falls between March 11 and May 5, a 55-day window. The first fall frost falls between October 8 and November 25.
- The median last frost is 5 days earlier than the Oregon median of Apr 16.
- Its 202-day growing season is longer than 56% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 26 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 60 nights a year at or below 32°F.
- Compared with Corvallis, OR, 27 km away, the last frost here is 6 days earlier than there and the growing season is 8 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 11 |
| 50% (median) | April 11 |
| 10% (safe for tender plants) | May 5 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 8 |
| 50% (median) | October 30 |
| 90% (late) | November 25 |
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 Monroe, OR
Monroe, OR frost dates — last frost Apr 11, first frost Oct 30, zone 8b. whenisthelastfrost.com
Crop
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Start indoors: Jan 17 to Jan 31Transplant outside: Mar 14 to Mar 28
Start indoors: Jan 31 to Feb 14Transplant outside: Apr 25 to May 9
Start indoors: Jan 31 to Feb 14Transplant outside: Apr 25 to May 9
Start indoors: Feb 14 to Feb 28Transplant outside: Apr 18 to May 2
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 21 to Apr 4Sow outdoors: Mar 14 to Apr 18Plant for fall: Sep 4 to Oct 2
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 14 to Mar 28Sow outdoors: Mar 14 to Mar 28Plant for fall: Aug 21 to Sep 11
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 28 to Apr 11Plant for fall: Jul 24 to Aug 14
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 21 to Apr 4Plant for fall: Jul 24 to Aug 14
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 28 to Apr 11Plant for fall: Jul 24 to Aug 14
Start indoors: Feb 28 to Mar 14Transplant outside: May 2 to May 16Sow outdoors: May 2 to May 16
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 18 to May 2
Sow outdoors: Feb 28 to Mar 21Plant for fall: Aug 7 to Aug 28
Sow outdoors: Feb 28 to Mar 21Plant for fall: Sep 4 to Sep 25
Sow outdoors: Mar 7 to Apr 18Plant for fall: Sep 18 to Oct 9
Start indoors: Mar 14 to Mar 21Transplant outside: Apr 25 to May 2Sow outdoors: Apr 18 to May 2Plant for fall: Aug 14 to Aug 28
Start indoors: Mar 14 to Mar 21Sow outdoors: Apr 18 to May 2Plant for fall: Aug 21 to Sep 4
Start indoors: Mar 14 to Mar 21Sow outdoors: Apr 18 to May 2
Start indoors: Mar 14 to Mar 21Transplant outside: Apr 25 to May 9
Sow outdoors: Mar 21 to Apr 18Plant for fall: Aug 7 to Aug 21
Sow outdoors: Mar 21 to Apr 18Plant for fall: Aug 21 to Sep 4
Sow outdoors: Mar 21 to Apr 11
Sow outdoors: Mar 28 to Apr 25Plant for fall: Aug 21 to Sep 4
Sow outdoors: Mar 28 to Apr 18Plant for fall: Sep 4 to Sep 25
Sow outdoors: Apr 18 to May 9Plant for fall: Aug 14 to Aug 28
Sow outdoors: Apr 18 to May 2
Transplant outside: Apr 25 to May 16
Plant for fall: Oct 16 to Nov 20
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Monroe, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 17 – Jan 31 | Mar 14 – Mar 28 | — | — |
| Peppers | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Eggplant | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Tomatoes | Feb 14 – Feb 28 | Apr 18 – May 2 | — | — |
| Lettuce | Feb 14 – Feb 28 | Mar 21 – Apr 4 | Mar 14 – Apr 18 | Sep 4 – Oct 2 |
| Kale | Feb 14 – Feb 28 | Mar 14 – Mar 28 | Mar 14 – Mar 28 | Aug 21 – Sep 11 |
| Broccoli | Feb 14 – Feb 28 | Mar 28 – Apr 11 | — | Jul 24 – Aug 14 |
| Cabbage | Feb 14 – Feb 28 | Mar 21 – Apr 4 | — | Jul 24 – Aug 14 |
| Cauliflower | Feb 14 – Feb 28 | Mar 28 – Apr 11 | — | Jul 24 – Aug 14 |
| Okra | Feb 28 – Mar 14 | May 2 – May 16 | May 2 – May 16 | — |
| Basil | Feb 28 – Mar 14 | Apr 18 – May 2 | — | — |
| Peas | — | — | Feb 28 – Mar 21 | Aug 7 – Aug 28 |
| Spinach | — | — | Feb 28 – Mar 21 | Sep 4 – Sep 25 |
| Radishes | — | — | Mar 7 – Apr 18 | Sep 18 – Oct 9 |
| Cucumbers | Mar 14 – Mar 21 | Apr 25 – May 2 | Apr 18 – May 2 | Aug 14 – Aug 28 |
| Zucchini & Summer Squash | Mar 14 – Mar 21 | — | Apr 18 – May 2 | Aug 21 – Sep 4 |
| Winter Squash & Pumpkins | Mar 14 – Mar 21 | — | Apr 18 – May 2 | — |
| Melons & Watermelon | Mar 14 – Mar 21 | Apr 25 – May 9 | — | — |
| Carrots | — | — | Mar 21 – Apr 18 | Aug 7 – Aug 21 |
| Beets | — | — | Mar 21 – Apr 18 | Aug 21 – Sep 4 |
| Potatoes | — | — | Mar 21 – Apr 11 | — |
| Swiss Chard | — | — | Mar 28 – Apr 25 | Aug 21 – Sep 4 |
| Cilantro | — | — | Mar 28 – Apr 18 | Sep 4 – Sep 25 |
| Green Beans | — | — | Apr 18 – May 9 | Aug 14 – Aug 28 |
| Sweet Corn | — | — | Apr 18 – May 2 | — |
| Sweet Potatoes | — | Apr 25 – May 16 | — | — |
| Garlic | — | — | — | Oct 16 – Nov 20 |
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 Corvallis 10 Ssw, OR weather station, 10 km away (elevation 312 ft (95 m)).
Frost dates near Monroe
- Harrisburg Apr 11 · Oct 23
- Junction City Apr 11 · Oct 23
- Cheshire Apr 11 · Oct 23
- Halsey Apr 11 · Oct 30
- Shedd Apr 11 · Oct 30
- Blachly Apr 18 · Oct 25
- Alvadore Apr 11 · Oct 23
- Alsea Apr 13 · Nov 3
- Philomath May 15 · Oct 8
- Elmira Apr 18 · Oct 25
Frequently asked questions
When is the last frost in Monroe, OR?
The median last spring frost in Monroe, OR is April 11. 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 Monroe, OR?
The median first fall frost is October 30, with about a 10% chance of frost before October 8.
How long is the growing season in Monroe, OR?
About 202 days between the median last spring frost and first fall frost.
What planting zone is Monroe, OR?
Monroe, OR is in USDA hardiness zone 8b.