Frost dates for 97903Brogan, OR
The average last spring frost in Brogan is May 7 and the average first fall frost is October 3, giving a typical growing season of about 147 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 7
- Average first fall frost
- Oct 3
- Growing season
- 147 days
Safer after May 28 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 186 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 7 · May 22 · Jun 15 | Sep 6 · Sep 22 · Oct 5 | 121 days | 100% |
| Frost / freeze (32°F) | Apr 23 · May 7 · May 28 | Sep 19 · Oct 3 · Oct 14 | 147 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 24 · May 11 | Sep 29 · Oct 13 · Oct 25 | 172 days | 100% |
Planting calendar for Brogan
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 6 – Jun 12 |
| Tomatoes | Transplant outdoors | May 23 – Jun 13 |
| Peppers | Start seeds indoors | Apr 6 – May 7 |
| Peppers | Transplant outdoors | Jun 6 – Jul 7 |
| Eggplant | Start seeds indoors | Apr 23 – May 22 |
| Eggplant | Transplant outdoors | Jun 6 – Jul 7 |
| Cucumbers | Sow outdoors | Jun 6 – Jun 23 |
| Summer squash | Sow outdoors | May 23 – Jul 7 |
| Winter squash & pumpkins | Sow outdoors | Jun 6 – Jul 7 |
| Snap beans | Sow outdoors | May 23 – Jul 16 |
| Sweet corn | Sow outdoors | May 23 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 6 – Jul 7 |
| Okra | Sow outdoors | May 30 – Jun 22 |
| Peas | Sow outdoors (spring) | Apr 6 – May 22 |
| Potatoes | Plant outdoors (spring) | Apr 6 – Jun 6 |
| Onions | Start seeds indoors (spring) | Feb 23 – Mar 22 |
| Onions | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (spring) | Mar 19 – Apr 22 |
| Broccoli | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 9 – Apr 6 |
| Cabbage | Transplant outdoors (spring) | Apr 6 – May 7 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 6 – Jun 22 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Mar 30 – May 13 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 6 – May 27 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 23 – May 13 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 7 – Jun 22 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 97903 is matched to the NOAA station Westfall, OR, 25.4 km away, at 3,040 ft elevation (713 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Westfall, OR (used) | 3,040 ft | May 7 | Oct 3 |
| Huntington, OR | 2,110 ft | Apr 23 | Oct 13 |
| Vale, OR | 2,240 ft | May 8 | Sep 29 |
| Weiser, ID | 2,120 ft | Apr 23 | Oct 13 |
Frost dates near Brogan
- Jamieson, OR 97909 · last Apr 23, first Oct 13
- Westfall, OR 97920 · last May 7, first Oct 3
- Huntington, OR 97907 · last Apr 23, first Oct 13
- Ironside, OR 97908 · last —, first —
- Vale, OR 97918 · last May 8, first Sep 29
- Bridgeport, OR 97819 · last May 25, first Sep 15
- Durkee, OR 97905 · last May 25, first Sep 15
- Harper, OR 97906 · last May 7, first Oct 5
Frequently asked questions
- When is the last frost in Brogan, OR?
- For ZIP code 97903, the average last spring frost (32°F) is May 7, based on NOAA 1991-2020 climate normals for the Westfall, OR weather station. There is a 1-in-10 chance of a frost after May 28.
- When is the first frost in Brogan, OR?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 97903?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 147 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.