Frost dates for 95987Williams, CA
The average last spring frost in Williams is February 14 and the average first fall frost is December 1, giving a typical growing season of about 293 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Feb 14
- Average first fall frost
- Dec 1
- Growing season
- 293 days
Safer after Mar 31 (1-in-10 risk)
Possible by Nov 11 (1-in-10 risk)
First frost typically in 30 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) | Feb 21 · Mar 31 · Apr 22 | Oct 28 · Nov 12 · Nov 30 | 228 days | 100% |
| Frost / freeze (32°F) | Jan 2 · Feb 14 · Mar 31 | Nov 11 · Dec 1 · Dec 26 | 293 days | 98% |
| Hard freeze (28°F) | Dec 11 · Jan 8 · Feb 20 | Nov 24 · Dec 15 · Jan 17 | 342 days | 75% |
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 | Jan 14 – Mar 22 |
| Tomatoes | Transplant outdoors | Mar 2 – Aug 11 |
| Peppers | Start seeds indoors | Jan 14 – Feb 14 |
| Peppers | Transplant outdoors | Mar 16 – Apr 16 |
| Eggplant | Start seeds indoors | Jan 31 – Mar 1 |
| Eggplant | Transplant outdoors | Mar 16 – Apr 16 |
| Cucumbers | Sow outdoors | Mar 16 – Aug 21 |
| Summer squash | Sow outdoors | Mar 2 – Apr 16 |
| Winter squash & pumpkins | Sow outdoors | Mar 16 – Apr 16 |
| Snap beans | Sow outdoors | Mar 2 – Sep 13 |
| Sweet corn | Sow outdoors | Mar 2 – Aug 11 |
| Watermelon & cantaloupe | Sow outdoors | Mar 16 – Apr 16 |
| Okra | Sow outdoors | Mar 9 – Apr 1 |
| Peas | Sow outdoors (spring) | Jan 14 – Mar 1 |
| Potatoes | Plant outdoors (spring) | Jan 14 – Mar 16 |
| Onions | Start seeds indoors (spring) | Dec 3 – Dec 30 |
| Onions | Transplant outdoors (spring) | Jan 31 – Mar 1 |
| Broccoli | Start seeds indoors (spring) | Dec 27 – Jan 30 |
| Broccoli | Transplant outdoors (spring) | Jan 31 – Mar 1 |
| Broccoli | Start seeds indoors (fall) | Aug 1 – Aug 11 |
| Broccoli | Transplant outdoors (fall) | Aug 31 – Sep 11 |
| Cabbage | Start seeds indoors (spring) | Dec 17 – Jan 14 |
| Cabbage | Transplant outdoors (spring) | Jan 14 – Feb 14 |
| Cabbage | Start seeds indoors (fall) | Jul 22 – Aug 21 |
| Cabbage | Transplant outdoors (fall) | Aug 21 – Sep 21 |
| Leaf lettuce | Sow outdoors (spring) | Jan 14 – Apr 1 |
| Leaf lettuce | Sow outdoors (fall) | Aug 21 – Oct 7 |
| Spinach | Sow outdoors (spring) | Jan 7 – Feb 20 |
| Spinach | Sow outdoors (fall) | Sep 7 – Oct 12 |
| Radishes | Sow outdoors (spring) | Jan 14 – Mar 6 |
| Radishes | Sow outdoors (fall) | Aug 21 – Oct 22 |
| Kale | Sow outdoors (spring) | Jan 31 – Feb 20 |
| Kale | Sow outdoors (fall) | Aug 14 – Sep 21 |
| Carrots | Sow outdoors (spring) | Feb 14 – Apr 1 |
| Carrots | Sow outdoors (fall) | Jul 22 – Sep 6 |
| Garlic | Plant outdoors (fall) | Nov 21 – Dec 22 |
Where these dates come from
ZIP code 95987 is matched to the NOAA station Colusa 2 Ssw, CA, 17.4 km away, at 50 ft elevation (75 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Colusa 2 Ssw, CA (used) | 50 ft | Feb 14 | Dec 1 |
| East Park Rsvr, CA | 1,205 ft | Apr 6 | Nov 10 |
| Clearlake 4 Se, CA | 1,349 ft | Apr 10 | Nov 6 |
| Willows 6 W, CA | 234 ft | Feb 21 | Dec 6 |
Frost dates near Williams
- Colusa, CA 95932 · last Feb 14, first Dec 1
- Maxwell, CA 95955 · last Feb 14, first Dec 1
- Arbuckle, CA 95912 · last Feb 14, first Dec 1
- Rumsey, CA 95679 · last Apr 10, first Nov 6
- Grimes, CA 95950 · last Feb 14, first Dec 1
- Guinda, CA 95637 · last Mar 6, first Nov 30
- Dunnigan, CA 95937 · last Feb 7, first Dec 5
- Princeton, CA 95970 · last Feb 14, first Dec 1
Frequently asked questions
- When is the last frost in Williams, CA?
- For ZIP code 95987, the average last spring frost (32°F) is February 14, based on NOAA 1991-2020 climate normals for the Colusa 2 Ssw, CA weather station. There is a 1-in-10 chance of a frost after March 31.
- When is the first frost in Williams, CA?
- The average first fall frost (32°F) is December 1. There is a 1-in-10 chance of frost by November 11, so tender plants are at risk from that point on.
- How long is the growing season in 95987?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 293 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.