Frost dates for 26187Williamstown, WV
The average last spring frost in Williamstown is April 18 and the average first fall frost is October 27, giving a typical growing season of about 191 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 27
- Growing season
- 191 days
Safer after May 4 (1-in-10 risk)
Possible by Oct 13 (1-in-10 risk)
Last frost typically in 166 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) | Apr 16 · Apr 30 · May 17 | Oct 3 · Oct 16 · Oct 29 | 169 days | 100% |
| Frost / freeze (32°F) | Apr 5 · Apr 18 · May 4 | Oct 13 · Oct 27 · Nov 6 | 191 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 5 · Apr 19 | Oct 24 · Nov 5 · Nov 19 | 214 days | 100% |
Planting calendar for Williamstown
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 | Mar 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jul 7 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 17 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 9 |
| Sweet corn | Sow outdoors | May 4 – Jul 7 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 27 – Jul 7 |
| Broccoli | Transplant outdoors (fall) | Jul 27 – Aug 7 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 17 – Jul 17 |
| Cabbage | Transplant outdoors (fall) | Jul 17 – Aug 17 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 17 – Sep 2 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Aug 3 – Sep 7 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 17 – Sep 17 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 10 – Aug 17 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 17 – Aug 2 |
| Garlic | Plant outdoors (fall) | Oct 17 – Nov 17 |
Where these dates come from
ZIP code 26187 is matched to the NOAA station Marietta Wwtp, OH, 3.6 km away, at 610 ft elevation (112 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Marietta Wwtp, OH (used) | 610 ft | Apr 18 | Oct 27 |
| Parkersburg Wood Co Ap, WV | 831 ft | Apr 23 | Oct 22 |
| Parkersburg, WV | 620 ft | Apr 14 | Oct 30 |
| Newport, OH | 676 ft | Apr 23 | Oct 26 |
Frost dates near Williamstown
- Marietta, OH 45750 · last Apr 18, first Oct 27
- Vienna, WV 26105 · last Apr 14, first Oct 30
- Waverly, WV 26184 · last Apr 23, first Oct 22
- Parkersburg, WV 26104 · last Apr 14, first Oct 30
- Fleming, OH 45729 · last Apr 23, first Oct 22
- Belpre, OH 45714 · last Apr 14, first Oct 30
- Whipple, OH 45788 · last Apr 23, first Oct 22
- Belmont, WV 26134 · last Apr 23, first Oct 26
Frequently asked questions
- When is the last frost in Williamstown, WV?
- For ZIP code 26187, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Marietta Wwtp, OH weather station. There is a 1-in-10 chance of a frost after May 4.
- When is the first frost in Williamstown, WV?
- The average first fall frost (32°F) is October 27. There is a 1-in-10 chance of frost by October 13, so tender plants are at risk from that point on.
- How long is the growing season in 26187?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 191 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.