Frost dates for 97544Williams, OR
The average last spring frost in Williams is May 4 and the average first fall frost is October 13, giving a typical growing season of about 160 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 4
- Average first fall frost
- Oct 13
- Growing season
- 160 days
Safer after May 23 (1-in-10 risk)
Possible by Sep 22 (1-in-10 risk)
Last frost typically in 183 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 5 · May 25 · Jun 15 | Sep 5 · Sep 26 · Oct 14 | 122 days | 100% |
| Frost / freeze (32°F) | Apr 15 · May 4 · May 23 | Sep 22 · Oct 13 · Oct 30 | 160 days | 100% |
| Hard freeze (28°F) | Mar 12 · Apr 6 · May 2 | Oct 8 · Nov 1 · Nov 23 | 202 days | 100% |
Planting calendar for Williams
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 3 – Jun 9 |
| Tomatoes | Transplant outdoors | May 20 – Jun 23 |
| Peppers | Start seeds indoors | Apr 3 – May 4 |
| Peppers | Transplant outdoors | Jun 3 – Jul 4 |
| Eggplant | Start seeds indoors | Apr 20 – May 19 |
| Eggplant | Transplant outdoors | Jun 3 – Jul 4 |
| Cucumbers | Sow outdoors | Jun 3 – Jul 3 |
| Summer squash | Sow outdoors | May 20 – Jul 4 |
| Winter squash & pumpkins | Sow outdoors | Jun 3 – Jul 4 |
| Snap beans | Sow outdoors | May 20 – Jul 26 |
| Sweet corn | Sow outdoors | May 20 – Jun 23 |
| Watermelon & cantaloupe | Sow outdoors | Jun 3 – Jul 4 |
| Okra | Sow outdoors | May 27 – Jun 19 |
| Peas | Sow outdoors (spring) | Apr 3 – May 19 |
| Potatoes | Plant outdoors (spring) | Apr 3 – Jun 3 |
| Onions | Start seeds indoors (spring) | Feb 20 – Mar 19 |
| Onions | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (spring) | Mar 16 – Apr 19 |
| Broccoli | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (fall) | Jun 13 – Jun 23 |
| Broccoli | Transplant outdoors (fall) | Jul 13 – Jul 24 |
| Cabbage | Start seeds indoors (spring) | Mar 6 – Apr 3 |
| Cabbage | Transplant outdoors (spring) | Apr 3 – May 4 |
| Cabbage | Start seeds indoors (fall) | Jun 3 – Jul 3 |
| Cabbage | Transplant outdoors (fall) | Jul 3 – Aug 3 |
| Leaf lettuce | Sow outdoors (spring) | Apr 3 – Jun 19 |
| Leaf lettuce | Sow outdoors (fall) | Jul 3 – Aug 19 |
| Spinach | Sow outdoors (spring) | Mar 27 – May 10 |
| Spinach | Sow outdoors (fall) | Jul 20 – Aug 24 |
| Radishes | Sow outdoors (spring) | Apr 3 – May 24 |
| Radishes | Sow outdoors (fall) | Jul 3 – Sep 3 |
| Kale | Sow outdoors (spring) | Apr 20 – May 10 |
| Kale | Sow outdoors (fall) | Jun 26 – Aug 3 |
| Carrots | Sow outdoors (spring) | May 4 – Jun 19 |
| Carrots | Sow outdoors (fall) | Jun 3 – Jul 19 |
| Garlic | Plant outdoors (fall) | Oct 3 – Nov 3 |
Where these dates come from
ZIP code 97544 is matched to the NOAA station Ruch, OR, 19.4 km away, at 1,550 ft elevation (106 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ruch, OR (used) | 1,550 ft | May 4 | Oct 13 |
| Grants Pass, OR | 932 ft | Apr 8 | Oct 28 |
| Cave Junction 1 Wnw, OR | 1,377 ft | May 1 | Oct 12 |
| Medford Rogue Vly Ap, OR | 1,297 ft | Apr 8 | Oct 29 |
Frost dates near Williams
- Murphy, OR 97533 · last May 4, first Oct 13
- Grants Pass, OR 97527 · last Apr 8, first Oct 28
- Jacksonville, OR 97530 · last May 4, first Oct 13
- Selma, OR 97538 · last May 1, first Oct 12
- Gold Hill, OR 97525 · last May 4, first Oct 13
- Wilderville, OR 97543 · last May 1, first Oct 12
- Cave Junction, OR 97523 · last May 1, first Oct 12
- Kerby, OR 97531 · last May 1, first Oct 12
Frequently asked questions
- When is the last frost in Williams, OR?
- For ZIP code 97544, the average last spring frost (32°F) is May 4, based on NOAA 1991-2020 climate normals for the Ruch, OR weather station. There is a 1-in-10 chance of a frost after May 23.
- When is the first frost in Williams, OR?
- The average first fall frost (32°F) is October 13. There is a 1-in-10 chance of frost by September 22, so tender plants are at risk from that point on.
- How long is the growing season in 97544?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 160 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.