Photo: DiskFool · Public domainMore precipitation falls on Pennington than on 77% of U.S. towns: 48 inches a year
The coldest hours of a January night bottom out at 23° on average. Expect the heaviest rain or snow in July and the lightest in February. Plan time outside from April to June and September to October, when highs sit at 63–82°.
A year in Pennington at a glance
Each month’s typical high and low, and what it brings.
What stands out about Pennington’s climate
Compared with towns across the U.S., with Pennington’s place in New Jersey beside it.
What a year in Pennington feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 202 frost-free days a year
In half of years the last 32° night comes by April 10 and the first by November 1. Frost and day counts come from NOAA’s station at Trenton Mercer Co Airport, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Pennington’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 4°. 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 27 inches of snow a winter
Snow, measured at Ewing Twp 0.8 Ese, NJ, is heaviest from January through February, about 8 inches a month. Precipitation (rain plus melted snow) adds up to 48 inches a year; July is the wettest month and February the driest. Rain or snow falls on about 130 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Pennington
83% of the work is heating. Months averaging under 55° run from November 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 Trenton Mercer Co Airport.
Living with Pennington’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
202 frost-free days in zone 7a. The last frost comes by Apr 10 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 1.
Months with highs of 62–84° and lows of 40° or more: April, May, June, September and October. 0.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Pennington from natural hazards, river flooding is the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 10%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Pennington and similar climates
TownRatings has no climate map of the towns around Pennington yet.
Climates most like Pennington’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 |
|---|---|---|---|---|
| Pennington, NJ | 23° | 86° | 48" | 27" |
| Walton, KY | 23° | 86° | 47" | 23" |
| Amelia, OH | 23° | 86° | 46" | 23" |
| Clarksburg, WV | 23° | 85° | 47" | 24" |
| Lawrenceburg, IN | 23° | 86° | 45" | 23" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Pennington averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.9°).
A bigger shift than in 96% 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 Pennington compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Pennington’s place among New Jersey’s.
Pennington weather by month
Highs, lows and precipitation from NOAA’s grid at Pennington’s center; snow, wet days and snow on the ground from Ewing Twp 0.8 Ese, NJ. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 40° | 23° | 3.5" | 8.2" | 11 | 24° – 39° |
| February | 43° | 24° | 2.7" | 8.7" | 11 | 22° – 40° |
| March | 51° | 31° | 4.2" | 4.0" | 11 | 36° – 51° |
| April | 63° | 40° | 3.7" | 0.5" | 12 | 48° – 56° |
| May | 73° | 50° | 4.0" | 0.0" | 14 | 57° – 67° |
| June | 82° | 60° | 4.4" | 0.0" | 12 | 67° – 74° |
| July | 86° | 65° | 5.1" | 0.0" | 11 | 71° – 79° |
| August | 85° | 63° | 4.3" | 0.0" | 11 | 70° – 77° |
| September | 78° | 56° | 4.3" | 0.0" | 8 | 64° – 71° |
| October | 66° | 45° | 4.2" | 0.1" | 10 | 50° – 62° |
| November | 55° | 35° | 3.4" | 0.5" | 8 | 40° – 50° |
| December | 45° | 28° | 4.3" | 4.6" | 11 | 29° – 48° |
| Year | 64° | 43° | 48.2" | 26.6" | 130 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 29° to 48°. September is the most reliable, staying within 7°.
Where Pennington’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 Pennington’s center.
- Snow: Ewing Twp 0.8 Ese, NJ.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Trenton Mercer Co Airport, 4 miles from the town’s center, at about the same height; 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 Pennington’s climate
What is the weather like in Pennington?
A typical July afternoon reaches 86°, a January night drops to 23°, and about 27 inches of snow falls in a normal winter. Milder January nights than 57% of U.S. towns; hotter July afternoons than 58% of U.S. towns.
How cold does it get in Pennington in winter?
January nights average 23°. About 97 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.
How much snow does Pennington get?
About 27 inches in a normal winter at Ewing Twp 0.8 Ese, NJ, heaviest from January through February, about 8 inches a month.
How hot does it get in Pennington?
July, with a typical high of 86° and a low of 65°. About 22 days a year reach 90° (Trenton Mercer Co Airport).
When is the first and last frost in Pennington?
In half of years the last spring frost (32°) comes by April 10 and the first fall frost by November 1, about 202 frost-free days, at Trenton Mercer Co Airport.
What growing zone is Pennington in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 4°.
What is the best time of year to visit Pennington?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Pennington getting warmer?
Yes: 1991–2020 averaged 2.2° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 96% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Pennington.
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.