Plymouth, Massachusetts climate: Normal weather by month, frost dates and records
Plymouth's normal year runs from 20°F January nights to 82°F July afternoons, with 48.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.0°C, January lows of −6°C, July highs of 28°C, 1,219 mm of precipitation a year.
- NOAA stationPlymouth Municipal Airport
- Station IDUSW00054769
- Location41.91°N 70.73°W
- Elevation149 ft (45 m)
- Population (town)66,663
- Census place7,852
On October 23, the normal high in Plymouth is 60°F and the normal low 40°F, and the chance of measurable rain or snow is 41%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Plymouth.
- Jan 38° 20°
- Feb 40° 21°
- Mar 46° 27°
- Apr 57° 36°
- May 67° 46°
- Jun 76° 55°
- Jul 82° 62°
- Aug 80° 61°
- Sep 73° 53°
- Oct 63° 42°
- Nov 53° 33°
- Dec 43° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Plymouth each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 20°F. The most precipitation falls in March (4.95 in), the least in February (2.96 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 38°F | 20°F | 29.2°F | 3.83 | 11 | <1 | 27 | 9 h 30 min |
| February | 40°F | 21°F | 30.5°F | 2.96 | 10 | <1 | 25 | 10 h 30 min |
| March | 46°F | 27°F | 36.8°F | 4.95 | 12 | <1 | 22 | 11 h 50 min |
| April | 57°F | 36°F | 46.1°F | 4.40 | 14 | <1 | 10 | 13 h 20 min |
| May | 67°F | 46°F | 56.4°F | 3.54 | 14 | <1 | 1 | 14 h 30 min |
| June | 76°F | 55°F | 65.7°F | 3.80 | 14 | 2 | <1 | 15 h 10 min |
| July | 82°F | 62°F | 71.9°F | 3.35 | 12 | 4 | <1 | 15 h |
| August | 80°F | 61°F | 70.5°F | 3.46 | 13 | 2 | <1 | 14 h |
| September | 73°F | 53°F | 63.2°F | 3.82 | 13 | <1 | <1 | 12 h 30 min |
| October | 63°F | 42°F | 52.4°F | 4.81 | 14 | <1 | 4 | 11 h 10 min |
| November | 53°F | 33°F | 42.9°F | 4.48 | 11 | <1 | 15 | 9 h 50 min |
| December | 43°F | 26°F | 34.6°F | 4.59 | 13 | <1 | 24 | 9 h 10 min |
| Year (annual) | 60°F | 40°F | 50.0°F | 47.99 | 151 | 9 | 127 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −6°C | −1.6°C | 97 mm |
| February | 4°C | −6°C | −0.8°C | 75 mm |
| March | 8°C | −3°C | 2.7°C | 126 mm |
| April | 14°C | 2°C | 7.8°C | 112 mm |
| May | 20°C | 8°C | 13.6°C | 90 mm |
| June | 24°C | 13°C | 18.7°C | 97 mm |
| July | 28°C | 17°C | 22.2°C | 85 mm |
| August | 27°C | 16°C | 21.4°C | 88 mm |
| September | 23°C | 12°C | 17.3°C | 97 mm |
| October | 17°C | 6°C | 11.3°C | 122 mm |
| November | 11°C | 1°C | 6.1°C | 114 mm |
| December | 6°C | −3°C | 1.4°C | 117 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Plymouth's own co-op station Plymouth-Kingston does: 38 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00054769; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Plymouth?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (12).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00054769.
When is the last frost in Plymouth?
In Plymouth, the last spring frost (32°F) comes after April 30 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 16 in half of years and before October 3 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 301 year in 10 after May 12; 9 in 10 after April 19
- First autumn frost, half of years before
- October 161 year in 10 before October 3; 9 in 10 before November 1
NOAA puts the median frost-free season at 170 days, and the season without a hard freeze (28°F) at 192 days.
A hard freeze (28°F) comes after April 18 in half of springs and before October 27 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Plymouth in zone 7a in ZIP code 02364, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Plymouth's NOAA station is in zone 6b: the coldest night of a typical year reaches −1°F (22 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Massachusetts · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00054769; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Plymouth?
In a normal year in Plymouth, 9 days a year reach 90°F, 127 nights fall to 32°F or colder and 151 days bring measurable precipitation.
- Days at 90°F or more
- 9a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 127a normal year
- Days that stay below freezing
- 22high of 32°F or less
- Days with 0.01 inch of precipitation
- 151a normal year
The highest temperature in this station's record (since 1996) is 101°F, on July 6, 2010; the lowest is −12°F, on February 21, 2015.
The wettest calendar year on that record is 2018, with 61.07 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00054769; records: ACIS (NOAA Regional Climate Centers), station USW00054769. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Plymouth, and how clear are its skies?
The summer (June-August) dew point averages 61°F. The muggiest month is July, with an average dew point of 63°F; the driest air comes in January (20°F). March is the windiest month (9.0 mph on average).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 20°F | 67% | 54% | 8.5 mph | – | – |
| February | 23°F | 66% | 52% | 8.9 mph | – | – |
| March | 30°F | 59% | 50% | 9.0 mph | – | – |
| April | 40°F | 67% | 50% | 8.0 mph | – | – |
| May | 52°F | 74% | 57% | 7.5 mph | – | – |
| June | 61°F | 73% | 55% | 6.8 mph | – | – |
| July | 63°F | 75% | 57% | 6.4 mph | – | – |
| August | 59°F | 75% | 57% | 6.2 mph | – | – |
| September | 52°F | 78% | 61% | 6.7 mph | – | – |
| October | 40°F | 73% | 58% | 7.8 mph | – | – |
| November | 31°F | 71% | 58% | 8.0 mph | – | – |
| December | 23°F | 70% | 58% | 8.5 mph | – | – |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00054769. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Plymouth?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Plymouth, 3.9 kWh per square metre a day. August is the sunniest month (80%) and December the cloudiest (65%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 67% | 1.8 |
| February | 70% | 2.7 |
| March | 70% | 3.7 |
| April | 72% | 4.9 |
| May | 72% | 5.5 |
| June | 74% | 5.9 |
| July | 80% | 6.0 |
| August | 80% | 5.4 |
| September | 79% | 4.4 |
| October | 72% | 3.0 |
| November | 70% | 2.0 |
| December | 65% | 1.5 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Plymouth need?
A normal year in Plymouth brings 6,019 heating degree days, 12% more than the median U.S. place (5,373), and 589 cooling degree days, 35% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,641 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,111 | 0 |
| February | 966 | 0 |
| March | 876 | 0 |
| April | 567 | 2 |
| May | 281 | 16 |
| June | 73 | 92 |
| July | 9 | 223 |
| August | 15 | 187 |
| September | 117 | 62 |
| October | 396 | 7 |
| November | 665 | 0 |
| December | 942 | 0 |
| Year (annual) | 6,019 | 589 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00054769. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Plymouth been warmer than normal lately?
2025 averaged 50.4°F, 0.4°F above the 1991-2020 normal of 50.0°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 52.1°F | +2.1°F | 52.83 |
| 2022 | 52.3°F | +2.3°F | 51.93 |
| 2023 | 53.0°F | +3.0°F | 52.35 |
| 2024 | 52.7°F | +2.7°F | 53.92 |
| 2025 | 50.4°F | +0.4°F | – |
Source: observed years: ACIS, station USW00054769. A year counts only with all twelve months complete.
How does Plymouth's climate compare?
Plymouth is warmer than 19 of the other 34 places with their own NOAA record in Massachusetts, and wetter than 19. Across the 7,247 U.S. stations with normals, its annual mean of 50.0°F is warmer than 40%.
In the Köppen classification computed from these normals, Plymouth is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Plymouth share this climate record?
9 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Kingston, MA14,462 people · 6 mi N
- The Pinehills, MA4,988 people · 7 mi E
- Marshfield, MA26,043 people · 13 mi N
- Ocean Bluff-Brant Rock, MA4,695 people · 14 mi N
- North Plymouth, MA4,458 people · 5 mi NE
- South Duxbury, MA3,272 people · 8 mi N
- Cedar Crest, MA2,289 people · 12 mi N
- Duxbury, MA16,377 people · 10 mi N
- Green Harbor, MA1,254 people · 12 mi N
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Plymouth's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Plymouth. This page uses Plymouth Municipal Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Plymouth-Kingston USC00196486 | 5 mi N | 45 ft | 52.6°F | 22°F | 84°F | 52.8 | 38 | April 15 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Plymouth's climate
What is the coldest month in Plymouth?
January, with a normal high of 38°F and a normal low of 20°F. The warmest is July (82°F by day, 62°F at night).
Does it snow in Plymouth?
Yes. NOAA publishes no 1991-2020 snowfall normal for Plymouth's NOAA station; Plymouth's own co-op station Plymouth-Kingston records 38 inches of snow in a normal year.
What is the rainiest month in Plymouth?
March, with 4.95 in of precipitation in a normal year; the driest is February with 2.96 in.
What plant hardiness zone is Plymouth in?
The USDA's 2023 map puts Plymouth in zone 7a in ZIP code 02364, the nearest ZIP area. By the same method at Plymouth's NOAA station, the coldest night of a typical year reaches −1°F (22 years, 1991-2020): zone 6b.
How late can frost come in Plymouth?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Plymouth in OctoberThis month day by day, its records and recent years
- Massachusetts climateThe statewide normals and every place in the state
- Middleboro, MA9 miles from this station, 49.5°F a year
- East Wareham, MA11 miles from this station, 50.7°F a year
- Bridgewater, MA12 miles from this station, 49.2°F a year
- Rochester, MA13 miles from this station, 50.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made