Photo: Doug Kerr · CC BY-SA 2.0Summers, winters and rain in Plymouth all run close to those of most U.S. towns
The coldest hours of a January night bottom out at 18° on average. By January nights alone, it runs colder than 69% of U.S. towns. Since 1901–2000, the year has warmed by 1.6°, most of all in December. Long walks are most pleasant from May to June and August to October, when afternoons reach 63–82°.
A year in Plymouth at a glance
Each month’s typical high and low, and what it brings.
What stands out about Plymouth’s climate
Compared with towns across the U.S., with Plymouth’s place in Pennsylvania beside it.
What a year in Plymouth feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 178 frost-free days a year
In half of years the last 32° night comes by April 23 and the first by October 20. Frost and day counts come from NOAA’s station at Wilkes-barre International Airport, 13 miles from the town’s center, 390 ft higher.
The 2023 USDA map puts Plymouth’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 0°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 36 inches of snow a winter
Snow, measured at Shickshinny 3 N, PA, is heaviest from January through February, about 10 inches a month. Precipitation (rain plus melted snow) adds up to 42 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 116 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Plymouth
88% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Wilkes-barre International Airport.
Living with Plymouth’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
178 frost-free days in zone 6b. The last frost comes by Apr 23 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 20.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October.
Parks & trails →Of the yearly building losses FEMA expects in Plymouth from natural hazards, river flooding is the largest share (78%); heat waves, cold waves, winter storms and ice storms together are 13%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Plymouth and its neighbors
Every town next door is within a degree of Plymouth in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Plymouth’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Plymouth, PA | 18° | 85° | 42" | 36" |
| Hartford City, IN | 19° | 84° | 41" | 32" |
| Palos Heights, IL | 17° | 84° | 39" | 39" |
| Mount Vernon, OH | 19° | 84° | 41" | 42" |
| Granby, MA | 16° | 84° | 45" | 37" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Plymouth averaged 1.6° warmer than the 1900s. The biggest change is in December (+3.3°).
A bigger shift than in 67% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Plymouth compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Plymouth’s place among Pennsylvania’s.
Plymouth weather by month
Highs, lows and precipitation from NOAA’s grid at Plymouth’s center; snow, wet days and snow on the ground from Shickshinny 3 N, PA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 35° | 18° | 3.0" | 10.7" | 10 | 18 | 17° – 35° |
| February | 38° | 20° | 2.2" | 10.2" | 8 | 16 | 17° – 36° |
| March | 47° | 27° | 3.1" | 6.0" | 9 | 8 | 30° – 49° |
| April | 61° | 37° | 3.7" | 0.8" | 10 | 0 | 44° – 54° |
| May | 72° | 47° | 3.6" | 0.0" | 11 | 0 | 55° – 66° |
| June | 80° | 56° | 3.9" | 0.0" | 11 | 0 | 65° – 72° |
| July | 85° | 61° | 3.9" | 0.0" | 10 | 0 | 68° – 77° |
| August | 82° | 59° | 4.1" | 0.0" | 10 | 0 | 66° – 74° |
| September | 75° | 52° | 4.2" | 0.0" | 9 | 0 | 60° – 68° |
| October | 63° | 41° | 4.0" | 0.2" | 9 | 0 | 47° – 59° |
| November | 50° | 32° | 2.9" | 1.1" | 8 | 2 | 35° – 46° |
| December | 40° | 25° | 3.1" | 6.6" | 10 | 9 | 23° – 44° |
| Year | 61° | 40° | 41.7" | 35.6" | 116 | 52 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 23° to 44°. June is the most reliable, staying within 7°.
Where Plymouth’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Plymouth’s center.
- Snow: Shickshinny 3 N, PA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Wilkes-barre International Airport, 13 miles from the town’s center, 390 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Plymouth’s climate
What is the weather like in Plymouth?
A typical July afternoon reaches 85°, a January night drops to 18°, and about 36 inches of snow falls in a normal winter. Colder January nights than 69% of U.S. towns; cooler July afternoons than 54% of U.S. towns.
How cold does it get in Plymouth in winter?
January nights average 18°. About 122 nights a year reach 32° or below and 3 reach 0° or below. In the coldest January of the last 30 years the month averaged 17°.
How much snow does Plymouth get?
About 36 inches in a normal winter at Shickshinny 3 N, PA, heaviest from January through February, about 10 inches a month, with snow on the ground about 52 days a year.
How hot does it get in Plymouth?
July, with a typical high of 85° and a low of 61°. About 12 days a year reach 90° (Wilkes-barre International Airport).
When is the first and last frost in Plymouth?
In half of years the last spring frost (32°) comes by April 23 and the first fall frost by October 20, about 178 frost-free days, at Wilkes-barre International Airport.
What growing zone is Plymouth in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 0°.
What is the best time of year to visit Plymouth?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Plymouth getting warmer?
Yes: 1991–2020 averaged 1.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 67% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Plymouth.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.