Frost dates for 02238Cambridge, MA
The average last spring frost in Cambridge is April 4 and the average first fall frost is November 9, giving a typical growing season of about 218 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 4
- Average first fall frost
- Nov 9
- Growing season
- 218 days
Safer after Apr 17 (1-in-10 risk)
Possible by Oct 29 (1-in-10 risk)
First frost typically in 8 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 6 · Apr 17 · May 1 | Oct 15 · Oct 29 · Nov 11 | 194 days | 100% |
| Frost / freeze (32°F) | Mar 25 · Apr 4 · Apr 17 | Oct 29 · Nov 9 · Nov 22 | 218 days | 100% |
| Hard freeze (28°F) | Mar 15 · Mar 28 · Apr 6 | Nov 8 · Nov 21 · Dec 5 | 239 days | 100% |
Planting calendar for Cambridge
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 4 – May 10 |
| Tomatoes | Transplant outdoors | Apr 20 – Jul 20 |
| Peppers | Start seeds indoors | Mar 4 – Apr 4 |
| Peppers | Transplant outdoors | May 4 – Jun 4 |
| Eggplant | Start seeds indoors | Mar 21 – Apr 19 |
| Eggplant | Transplant outdoors | May 4 – Jun 4 |
| Cucumbers | Sow outdoors | May 4 – Jul 30 |
| Summer squash | Sow outdoors | Apr 20 – Jun 4 |
| Winter squash & pumpkins | Sow outdoors | May 4 – Jun 4 |
| Snap beans | Sow outdoors | Apr 20 – Aug 22 |
| Sweet corn | Sow outdoors | Apr 20 – Jul 20 |
| Watermelon & cantaloupe | Sow outdoors | May 4 – Jun 4 |
| Okra | Sow outdoors | Apr 27 – May 20 |
| Peas | Sow outdoors (spring) | Mar 4 – Apr 19 |
| Potatoes | Plant outdoors (spring) | Mar 4 – May 4 |
| Onions | Start seeds indoors (spring) | Jan 21 – Feb 17 |
| Onions | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (spring) | Feb 14 – Mar 20 |
| Broccoli | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (fall) | Jul 10 – Jul 20 |
| Broccoli | Transplant outdoors (fall) | Aug 9 – Aug 20 |
| Cabbage | Start seeds indoors (spring) | Feb 4 – Mar 4 |
| Cabbage | Transplant outdoors (spring) | Mar 4 – Apr 4 |
| Cabbage | Start seeds indoors (fall) | Jun 30 – Jul 30 |
| Cabbage | Transplant outdoors (fall) | Jul 30 – Aug 30 |
| Leaf lettuce | Sow outdoors (spring) | Mar 4 – May 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 30 – Sep 15 |
| Spinach | Sow outdoors (spring) | Feb 25 – Apr 10 |
| Spinach | Sow outdoors (fall) | Aug 16 – Sep 20 |
| Radishes | Sow outdoors (spring) | Mar 4 – Apr 24 |
| Radishes | Sow outdoors (fall) | Jul 30 – Sep 30 |
| Kale | Sow outdoors (spring) | Mar 21 – Apr 10 |
| Kale | Sow outdoors (fall) | Jul 23 – Aug 30 |
| Carrots | Sow outdoors (spring) | Apr 4 – May 20 |
| Carrots | Sow outdoors (fall) | Jun 30 – Aug 15 |
| Garlic | Plant outdoors (fall) | Oct 30 – Nov 30 |
Where these dates come from
ZIP code 02238 is matched to the NOAA station Boston Logan Intl Ap, MA, 8 km away, at 12 ft elevation (8 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Boston Logan Intl Ap, MA (used) | 12 ft | Apr 4 | Nov 9 |
| Jamaica Plain, MA | 95 ft | Apr 19 | Oct 23 |
| Reading, MA | 110 ft | Apr 25 | Oct 17 |
| Blue Hill, MA | 625 ft | Apr 19 | Oct 24 |
Frost dates near Cambridge
- Somerville, MA 02143 · last Apr 4, first Nov 9
- Cambridge, MA 02139 · last Apr 4, first Nov 9
- Boston, MA 02215 · last Apr 4, first Nov 9
- Allston, MA 02134 · last Apr 19, first Oct 23
- Charlestown, MA 02129 · last Apr 4, first Nov 9
- Brookline, MA 02446 · last Apr 19, first Oct 23
- Medford, MA 02155 · last Apr 4, first Nov 9
- Brookline Village, MA 02447 · last Apr 19, first Oct 23
Frequently asked questions
- When is the last frost in Cambridge, MA?
- For ZIP code 02238, the average last spring frost (32°F) is April 4, based on NOAA 1991-2020 climate normals for the Boston Logan Intl Ap, MA weather station. There is a 1-in-10 chance of a frost after April 17.
- When is the first frost in Cambridge, MA?
- The average first fall frost (32°F) is November 9. There is a 1-in-10 chance of frost by October 29, so tender plants are at risk from that point on.
- How long is the growing season in 02238?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 218 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.