Frost dates for 97828Enterprise, OR
The average last spring frost in Enterprise is May 24 and the average first fall frost is October 1, giving a typical growing season of about 126 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 24
- Average first fall frost
- Oct 1
- Growing season
- 126 days
Safer after Jul 6 (1-in-10 risk)
Possible by Sep 10 (1-in-10 risk)
Last frost typically in 202 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) | — | — | 86 days | 100% |
| Frost / freeze (32°F) | May 6 · May 24 · Jul 6 | Sep 10 · Oct 1 · Oct 15 | 126 days | 100% |
| Hard freeze (28°F) | Apr 21 · May 4 · May 26 | Sep 29 · Oct 13 · Oct 30 | 160 days | 100% |
Planting calendar for Enterprise
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 23 – Jun 29 |
| Tomatoes | Transplant outdoors | Jun 9 – Jun 11 |
| Peppers | Start seeds indoors | Apr 23 – May 24 |
| Peppers | Transplant outdoors | Jun 23 – Jul 24 |
| Eggplant | Start seeds indoors | May 10 – Jun 8 |
| Eggplant | Transplant outdoors | Jun 23 – Jul 24 |
| Cucumbers | Sow outdoors | Jun 23 – Jun 21 |
| Summer squash | Sow outdoors | Jun 9 – Jul 24 |
| Winter squash & pumpkins | Sow outdoors | Jun 23 – Jul 24 |
| Snap beans | Sow outdoors | Jun 9 – Jul 14 |
| Sweet corn | Sow outdoors | Jun 9 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 23 – Jul 24 |
| Okra | Sow outdoors | Jun 16 – Jul 9 |
| Peas | Sow outdoors (spring) | Apr 23 – Jun 8 |
| Potatoes | Plant outdoors (spring) | Apr 23 – Jun 23 |
| Onions | Start seeds indoors (spring) | Mar 12 – Apr 8 |
| Onions | Transplant outdoors (spring) | May 10 – Jun 8 |
| Broccoli | Start seeds indoors (spring) | Apr 5 – May 9 |
| Broccoli | Transplant outdoors (spring) | May 10 – Jun 8 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 26 – Apr 23 |
| Cabbage | Transplant outdoors (spring) | Apr 23 – May 24 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 23 – Jul 9 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Apr 16 – May 30 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 23 – Jun 13 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | May 10 – May 30 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 24 – Jul 9 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 97828 is matched to the NOAA station Joseph, OR, 10.9 km away, at 4,184 ft elevation (457 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Joseph, OR (used) | 4,184 ft | May 24 | Oct 1 |
| Wallowa, OR | 2,923 ft | Jun 7 | Sep 9 |
| Enterprise 20 Nne, OR | 3,280 ft | Jun 8 | Sep 5 |
| Elgin, OR | 2,697 ft | May 24 | Sep 18 |
Frost dates near Enterprise
- Joseph, OR 97846 · last May 24, first Oct 1
- Lostine, OR 97857 · last Jun 7, first Sep 9
- Wallowa, OR 97885 · last Jun 7, first Sep 9
- Imnaha, OR 97842 · last Jun 8, first Sep 5
- Cove, OR 97824 · last May 11, first Sep 26
- Union, OR 97883 · last May 11, first Sep 26
- Elgin, OR 97827 · last May 24, first Sep 18
- Imbler, OR 97841 · last May 6, first Oct 1
Frequently asked questions
- When is the last frost in Enterprise, OR?
- For ZIP code 97828, the average last spring frost (32°F) is May 24, based on NOAA 1991-2020 climate normals for the Joseph, OR weather station. There is a 1-in-10 chance of a frost after July 6.
- When is the first frost in Enterprise, OR?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 10, so tender plants are at risk from that point on.
- How long is the growing season in 97828?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 126 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.