Precipitation in Derry tops that of 73% of U.S. towns: 48 inches a year
Sunny July days climb to about 83°. Expect the heaviest rain or snow in June and the lightest in February. Its July afternoons stay fresher than in 66% of U.S. towns. Garden chairs stay out from May to October, the months with highs of 64–83°.
A year in Derry at a glance
Each month’s typical high and low, and what it brings.
What stands out about Derry’s climate
Compared with towns across the U.S., with Derry’s place in Pennsylvania beside it.
What a year in Derry feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 152 frost-free days a year
In half of years the last 32° night comes by May 5 and the first by October 6. Frost and day counts come from NOAA’s station at Rector 3 Ssw, PA, 12 miles from the town’s center, 130 ft higher.
The 2023 USDA map puts Derry’s center in zone 6b: 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 48 inches of snow a winter
Snow, measured at Derry 4 Sw, PA, falls mostly in January. Precipitation (rain plus melted snow) adds up to 48 inches a year; June is the wettest month and February the driest. Rain or snow falls on about 140 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Derry
91% 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 Rector 3 Ssw, PA.
Living with Derry’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
152 frost-free days in zone 6b. The last frost comes by May 5 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 6.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 0.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Derry from natural hazards, river flooding is the largest share (85%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Derry and similar climates
TownRatings has no climate map of the towns around Derry yet.
Climates most like Derry’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 |
|---|---|---|---|---|
| Derry, PA | 21° | 83° | 48" | 48" |
| Wilton, CT | 20° | 84° | 49" | 49" |
| Lewisboro, NY | 20° | 84° | 49" | 49" |
| Valley Falls, RI | 20° | 83° | 50" | 48" |
| Attleboro, MA | 20° | 83° | 50" | 48" |
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 Derry averaged 0.8° warmer than the 1900s. The biggest change is in December (+2.1°).
A smaller shift than in 90% 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 Derry compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Derry’s place among Pennsylvania’s.
Derry weather by month
Highs, lows and precipitation from NOAA’s grid at Derry’s center; snow, wet days and snow on the ground from Derry 4 Sw, PA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 37° | 21° | 3.5" | 14.6" | 15 | 14 | 21° – 38° |
| February | 41° | 22° | 3.1" | 10.7" | 12 | 12 | 18° – 40° |
| March | 50° | 29° | 3.8" | 9.6" | 13 | 6 | 33° – 50° |
| April | 63° | 38° | 4.1" | 0.8" | 13 | 1 | 46° – 56° |
| May | 72° | 48° | 4.4" | 0.0" | 13 | 0 | 54° – 67° |
| June | 80° | 57° | 4.8" | 0.0" | 11 | 0 | 64° – 70° |
| July | 83° | 61° | 4.6" | 0.0" | 11 | 0 | 68° – 77° |
| August | 82° | 59° | 4.3" | 0.0" | 9 | 0 | 67° – 75° |
| September | 76° | 53° | 4.2" | 0.0" | 9 | 0 | 61° – 69° |
| October | 64° | 42° | 3.5" | 0.3" | 9 | 0 | 49° – 59° |
| November | 52° | 33° | 3.6" | 2.2" | 12 | 2 | 36° – 48° |
| December | 42° | 26° | 3.8" | 10.0" | 13 | 10 | 24° – 45° |
| Year | 62° | 41° | 47.6" | 48.2" | 140 | 44 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 18° to 40°. June is the most reliable, staying within 6°.
Where Derry’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 Derry’s center.
- Snow: Derry 4 Sw, PA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Rector 3 Ssw, PA, 12 miles from the town’s center, 130 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 Derry’s climate
What is the weather like in Derry?
A typical July afternoon reaches 83°, a January night drops to 21°, and about 48 inches of snow falls in a normal winter. Colder January nights than 56% of U.S. towns; cooler July afternoons than 66% of U.S. towns.
How cold does it get in Derry in winter?
January nights average 21°. About 154 nights a year reach 32° or below and 8 reach 0° or below. In the coldest January of the last 30 years the month averaged 21°.
How much snow does Derry get?
About 48 inches in a normal winter at Derry 4 Sw, PA, most of it in January, with snow on the ground about 44 days a year.
How hot does it get in Derry?
July, with a typical high of 83° and a low of 61°. About 11 days a year reach 90° (Rector 3 Ssw, PA).
When is the first and last frost in Derry?
In half of years the last spring frost (32°) comes by May 5 and the first fall frost by October 6, about 152 frost-free days, at Rector 3 Ssw, PA.
What growing zone is Derry in?
Zone 6b 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 Derry?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Derry getting warmer?
Yes: 1991–2020 averaged 0.8° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 90% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Derry.
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.