USDA Hardiness Zone 7b
Frost Dates for 02638 — Dennis, Massachusetts
NOAA 1991–2020 normals from W Harwich, MA (15 ft), 6 miles southeast.
Updated
In Dennis, the last spring frost (32°F) is around April 13 in half of years and has passed by April 26 in nine years out of ten. The first fall frost comes around November 3, as early as October 22 one year in ten, leaving a typical freeze-free season of 204 days (NOAA, W Harwich, MA).
- Last spring frost
- April 13
- First fall frost
- November 3
- Growing season
- 204 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- January 2
- Last snow
- March 6
- Winters with snow
- 86%
- Snow per year
- 21.5"
median, 1991–2020
median, 1991–2020
24 of 28 observed
NOAA normal
Frost risk by date in Dennis
Half of springs at W Harwich, MA see their last 32°F night by April 13; only one in ten is past it by April 2, and one in ten still has one after April 26. Planting tender crops after April 18 leaves a 30% risk of a frost on them, after April 21 20%, and after April 26 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 51% of the 71 Massachusetts stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 3 in half of years, as early as October 22 one year in ten, and holds off past November 18 one year in ten. A hard freeze of 28°F follows 14 days later, around November 17; in spring the one-in-ten date for 28°F is April 12, 14 days before the 32°F one. The freeze-free season lasts 204 days in a typical year, longer than at 93% of the 71 Massachusetts stations; it reaches 223 days one year in ten and falls short of 186 one year in ten. On average 94 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 14 days longer, to about April 27, and return around October 22. Severe cold of 16°F or below comes every winter, usually between December 26 and March 1.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Apr 20 | Apr 22 | Apr 24 | Apr 27 | Apr 29 | May 2 | May 6 | May 11 |
| 32°F | Apr 2 | Apr 5 | Apr 8 | Apr 10 | Apr 13 | Apr 16 | Apr 18 | Apr 21 | Apr 26 |
| 28°F | Mar 18 | Mar 22 | Mar 27 | Mar 30 | Apr 1 | Apr 3 | Apr 5 | Apr 8 | Apr 12 |
| 24°F | Mar 5 | Mar 10 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 27 | Mar 31 | Apr 3 |
| 20°F | Feb 23 | Mar 1 | Mar 4 | Mar 7 | Mar 10 | Mar 13 | Mar 17 | Mar 20 | Mar 26 |
| 16°F | Feb 8 | Feb 14 | Feb 21 | Feb 25 | Mar 1 | Mar 4 | Mar 7 | Mar 11 | Mar 18 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 8 | Oct 13 | Oct 17 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 31 | Nov 5 |
| 32°F | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
| 28°F | Nov 2 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 23 | Nov 28 | Dec 4 |
| 24°F | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 19 |
| 20°F | Nov 26 | Dec 1 | Dec 5 | Dec 9 | Dec 13 | Dec 18 | Dec 22 | Dec 26 | Jan 1 |
| 16°F | Dec 7 | Dec 13 | Dec 19 | Dec 22 | Dec 26 | Dec 30 | Jan 2 | Jan 7 | Jan 15 |
Freeze probabilities 1991–2020 at W Harwich, MA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 02638 →Compare Dennis with another place →
Compared with the next station
The nearest other station, Hyannis Barnstable Municipal Airport, MA, 7 miles southwest of Dennis, has a last frost 9 days later (April 22), a first frost 6 days earlier (October 28), a season 16 days shorter.
When it snows in Dennis, Massachusetts
The first measurable snow (0.1 inch or more) in Dennis usually arrives around January 2, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Hyannis, MA, 7.6 miles away: half of years saw snow earlier, half later. Snow fell in 86% of those winters. The last 32°F night of spring typically comes 38 days after the last snow.
Planting calendar for 02638
| When | What to do |
|---|---|
| February 2 – February 16 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 16 – March 2 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 16 – March 30 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 13 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 20 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 3 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 02638 is 6 miles from W Harwich, MA, which stands at 15 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 02660 (South Dennis). The 2023 USDA Plant Hardiness Zone Map lists ZIP 02638 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Massachusetts →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.