Frost dates for 97864Monument, OR
The average last spring frost in Monument is May 9 and the average first fall frost is September 27, giving a typical growing season of about 139 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 9
- Average first fall frost
- Sep 27
- Growing season
- 139 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 9 (1-in-10 risk)
Last frost typically in 189 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 11 · May 30 · Jun 20 | Aug 30 · Sep 12 · Sep 27 | 107 days | 100% |
| Frost / freeze (32°F) | Apr 25 · May 9 · May 26 | Sep 9 · Sep 27 · Oct 10 | 139 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 23 · May 8 | Sep 25 · Oct 9 · Oct 27 | 168 days | 100% |
Planting calendar for Monument
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 8 – Jun 14 |
| Tomatoes | Transplant outdoors | May 25 – Jun 7 |
| Peppers | Start seeds indoors | Apr 8 – May 9 |
| Peppers | Transplant outdoors | Jun 8 – Jul 9 |
| Eggplant | Start seeds indoors | Apr 25 – May 24 |
| Eggplant | Transplant outdoors | Jun 8 – Jul 9 |
| Cucumbers | Sow outdoors | Jun 8 – Jun 17 |
| Summer squash | Sow outdoors | May 25 – Jul 9 |
| Winter squash & pumpkins | Sow outdoors | Jun 8 – Jul 9 |
| Snap beans | Sow outdoors | May 25 – Jul 10 |
| Sweet corn | Sow outdoors | May 25 – Jun 7 |
| Watermelon & cantaloupe | Sow outdoors | Jun 8 – Jul 9 |
| Okra | Sow outdoors | Jun 1 – Jun 24 |
| Peas | Sow outdoors (spring) | Apr 8 – May 24 |
| Potatoes | Plant outdoors (spring) | Apr 8 – Jun 8 |
| Onions | Start seeds indoors (spring) | Feb 25 – Mar 24 |
| Onions | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (spring) | Mar 21 – Apr 24 |
| Broccoli | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (fall) | May 28 – Jun 7 |
| Broccoli | Transplant outdoors (fall) | Jun 27 – Jul 8 |
| Cabbage | Start seeds indoors (spring) | Mar 11 – Apr 8 |
| Cabbage | Transplant outdoors (spring) | Apr 8 – May 9 |
| Cabbage | Start seeds indoors (fall) | May 18 – Jun 17 |
| Cabbage | Transplant outdoors (fall) | Jun 17 – Jul 18 |
| Leaf lettuce | Sow outdoors (spring) | Apr 8 – Jun 24 |
| Leaf lettuce | Sow outdoors (fall) | Jun 17 – Aug 3 |
| Spinach | Sow outdoors (spring) | Apr 1 – May 15 |
| Spinach | Sow outdoors (fall) | Jul 4 – Aug 8 |
| Radishes | Sow outdoors (spring) | Apr 8 – May 29 |
| Radishes | Sow outdoors (fall) | Jun 17 – Aug 18 |
| Kale | Sow outdoors (spring) | Apr 25 – May 15 |
| Kale | Sow outdoors (fall) | Jun 10 – Jul 18 |
| Carrots | Sow outdoors (spring) | May 9 – Jun 24 |
| Carrots | Sow outdoors (fall) | May 18 – Jul 3 |
| Garlic | Plant outdoors (fall) | Sep 17 – Oct 18 |
Where these dates come from
ZIP code 97864 is matched to the NOAA station Monument 2, OR, 0.1 km away, at 1,995 ft elevation (13 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Monument 2, OR (used) | 1,995 ft | May 9 | Sep 27 |
| Long Creek, OR | 3,740 ft | Jun 5 | Sep 14 |
| Dayville 8 Nw, OR | 2,260 ft | May 4 | Oct 6 |
| John Day 35 Wnw, OR | 2,245 ft | Apr 30 | Oct 14 |
Frost dates near Monument
- Kimberly, OR 97848 · last Jun 5, first Sep 14
- Long Creek, OR 97856 · last Jun 5, first Sep 14
- Spray, OR 97874 · last Apr 30, first Oct 14
- Dayville, OR 97825 · last May 4, first Oct 6
- Ukiah, OR 97880 · last Jun 5, first Sep 14
- Mount Vernon, OR 97865 · last May 28, first Sep 18
- Fossil, OR 97830 · last May 22, first Oct 4
- John Day, OR 97845 · last May 28, first Sep 18
Frequently asked questions
- When is the last frost in Monument, OR?
- For ZIP code 97864, the average last spring frost (32°F) is May 9, based on NOAA 1991-2020 climate normals for the Monument 2, OR weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Monument, OR?
- The average first fall frost (32°F) is September 27. There is a 1-in-10 chance of frost by September 9, so tender plants are at risk from that point on.
- How long is the growing season in 97864?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 139 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.