Frost dates for 94542Hayward, CA
The average last spring frost in Hayward is February 27 and the average first fall frost is December 1, giving a typical growing season of about 278 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Feb 27
- Average first fall frost
- Dec 1
- Growing season
- 278 days
Safer after Mar 29 (1-in-10 risk)
Possible by Nov 14 (1-in-10 risk)
First frost typically in 35 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) | Mar 10 · Apr 1 · Apr 22 | Nov 2 · Nov 16 · Dec 1 | 227 days | 100% |
| Frost / freeze (32°F) | Jan 22 · Feb 27 · Mar 29 | Nov 14 · Dec 1 · Dec 22 | 278 days | 100% |
| Hard freeze (28°F) | Dec 19 · Jan 19 · Feb 23 | Nov 27 · Dec 15 · Jan 13 | 335 days | 85% |
Planting calendar for Hayward
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 27 – Apr 4 |
| Tomatoes | Transplant outdoors | Mar 15 – Aug 11 |
| Peppers | Start seeds indoors | Jan 27 – Feb 27 |
| Peppers | Transplant outdoors | Mar 29 – Apr 29 |
| Eggplant | Start seeds indoors | Feb 13 – Mar 14 |
| Eggplant | Transplant outdoors | Mar 29 – Apr 29 |
| Cucumbers | Sow outdoors | Mar 29 – Aug 21 |
| Summer squash | Sow outdoors | Mar 15 – Apr 29 |
| Winter squash & pumpkins | Sow outdoors | Mar 29 – Apr 29 |
| Snap beans | Sow outdoors | Mar 15 – Sep 13 |
| Sweet corn | Sow outdoors | Mar 15 – Aug 11 |
| Watermelon & cantaloupe | Sow outdoors | Mar 29 – Apr 29 |
| Okra | Sow outdoors | Mar 22 – Apr 14 |
| Peas | Sow outdoors (spring) | Jan 27 – Mar 14 |
| Potatoes | Plant outdoors (spring) | Jan 27 – Mar 29 |
| Onions | Start seeds indoors (spring) | Dec 16 – Jan 12 |
| Onions | Transplant outdoors (spring) | Feb 13 – Mar 14 |
| Broccoli | Start seeds indoors (spring) | Jan 9 – Feb 12 |
| Broccoli | Transplant outdoors (spring) | Feb 13 – Mar 14 |
| Broccoli | Start seeds indoors (fall) | Aug 1 – Aug 11 |
| Broccoli | Transplant outdoors (fall) | Aug 31 – Sep 11 |
| Cabbage | Start seeds indoors (spring) | Dec 30 – Jan 27 |
| Cabbage | Transplant outdoors (spring) | Jan 27 – Feb 27 |
| Cabbage | Start seeds indoors (fall) | Jul 22 – Aug 21 |
| Cabbage | Transplant outdoors (fall) | Aug 21 – Sep 21 |
| Leaf lettuce | Sow outdoors (spring) | Jan 27 – Apr 14 |
| Leaf lettuce | Sow outdoors (fall) | Aug 21 – Oct 7 |
| Spinach | Sow outdoors (spring) | Jan 20 – Mar 5 |
| Spinach | Sow outdoors (fall) | Sep 7 – Oct 12 |
| Radishes | Sow outdoors (spring) | Jan 27 – Mar 19 |
| Radishes | Sow outdoors (fall) | Aug 21 – Oct 22 |
| Kale | Sow outdoors (spring) | Feb 13 – Mar 5 |
| Kale | Sow outdoors (fall) | Aug 14 – Sep 21 |
| Carrots | Sow outdoors (spring) | Feb 27 – Apr 14 |
| Carrots | Sow outdoors (fall) | Jul 22 – Sep 6 |
| Garlic | Plant outdoors (fall) | Nov 21 – Dec 22 |
Where these dates come from
ZIP code 94542 is matched to the NOAA station Livermore Muni Ap, CA, 20.8 km away, at 393 ft elevation (243 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Livermore Muni Ap, CA (used) | 393 ft | Feb 27 | Dec 1 |
| Hayward Air Terminal, CA | 43 ft | Jan 2 | Dec 25 |
| Fremont, CA | 38 ft | Jan 7 | Dec 22 |
| Newark, CA | 10 ft | Jan 1 | Dec 27 |
Frost dates near Hayward
- Hayward, CA 94544 · last Jan 2, first Dec 25
- Castro Valley, CA 94546 · last Jan 2, first Dec 25
- San Lorenzo, CA 94580 · last Jan 2, first Dec 25
- Union City, CA 94587 · last Jan 7, first Dec 22
- San Leandro, CA 94578 · last Jan 2, first Dec 25
- Fremont, CA 94555 · last Jan 7, first Dec 22
- Dublin, CA 94568 · last Feb 15, first Dec 2
- Newark, CA 94560 · last Jan 7, first Dec 22
Frequently asked questions
- When is the last frost in Hayward, CA?
- For ZIP code 94542, the average last spring frost (32°F) is February 27, based on NOAA 1991-2020 climate normals for the Livermore Muni Ap, CA weather station. There is a 1-in-10 chance of a frost after March 29.
- When is the first frost in Hayward, CA?
- The average first fall frost (32°F) is December 1. There is a 1-in-10 chance of frost by November 14, so tender plants are at risk from that point on.
- How long is the growing season in 94542?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 278 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.