Photo: Eric Lewis · CC BY-SA 2.0Caln Township’s winters are milder but snowier than most of the U.S.
A typical July afternoon reaches 86°, a January night drops to 22°, and about 32 inches of snow falls in a normal winter.
A year in Caln Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Caln Township’s climate
Compared with towns across the U.S., with Caln Township’s place in Pennsylvania beside it.
What a year in Caln Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 190 frost-free days a year
In half of years the last 32° night comes by April 19 and the first by October 25. Frost and day counts come from NOAA’s station at Coatesville 2 W, PA, 5 miles from the town’s center, 260 ft higher.
The 2023 USDA map puts Caln Township’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 1°. 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 32 inches of snow a winter
Snow, measured at Coatesville 2 W, PA, falls mostly in February. Precipitation (rain plus melted snow) adds up to 48 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 131 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Caln Township
85% 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 Coatesville 2 W, PA.
Living with Caln Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
190 frost-free days in zone 7a. The last frost comes by Apr 19 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 25.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 3.8 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Caln Township from natural hazards, river flooding is the largest share (72%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Caln Township and its neighbors
Downingtown the hottest July afternoons (87°, 1° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Caln Township’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 |
|---|---|---|---|---|
| Caln Township, PA | 22° | 86° | 48" | 32" |
| Fairfield, CT | 22° | 84° | 49" | 34" |
| New Martinsville, WV | 22° | 85° | 46" | 27" |
| Elsmere, KY | 23° | 85° | 47" | 23" |
| Delhi Hills, OH | 23° | 86° | 46" | 23" |
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 Caln Township averaged 1.8° warmer than the 1900s. The biggest change is in December (+3.4°).
A bigger shift than in 81% 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 Caln Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Caln Township’s place among Pennsylvania’s.
Caln Township weather by month
Highs, lows and precipitation from NOAA’s grid at Caln Township’s center; snow, wet days and snow on the ground from Coatesville 2 W, PA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 39° | 22° | 3.4" | 7.9" | 12 | 11 | 22° – 38° |
| February | 42° | 23° | 2.8" | 11.5" | 10 | 13 | 22° – 41° |
| March | 51° | 30° | 4.2" | 6.3" | 12 | 5 | 35° – 49° |
| April | 63° | 40° | 3.8" | 1.1" | 12 | 0 | 47° – 57° |
| May | 73° | 50° | 3.8" | 0.0" | 11 | 0 | 57° – 67° |
| June | 81° | 59° | 4.5" | 0.0" | 11 | 0 | 67° – 74° |
| July | 86° | 65° | 4.7" | 0.0" | 11 | 0 | 71° – 79° |
| August | 84° | 63° | 4.3" | 0.0" | 10 | 0 | 69° – 77° |
| September | 77° | 55° | 4.9" | 0.0" | 10 | 0 | 63° – 70° |
| October | 65° | 43° | 4.4" | 0.0" | 9 | 0 | 50° – 61° |
| November | 54° | 34° | 3.3" | 0.7" | 10 | 1 | 39° – 49° |
| December | 44° | 27° | 4.1" | 4.4" | 11 | 6 | 27° – 47° |
| Year | 63° | 43° | 48.2" | 31.9" | 131 | 35 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 27° to 47°. September is the most reliable, staying within 7°.
Where Caln Township’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 Caln Township’s center.
- Snow: Coatesville 2 W, PA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Coatesville 2 W, PA, 5 miles from the town’s center, 260 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 Caln Township’s climate
What is the weather like in Caln Township?
A typical July afternoon reaches 86°, a January night drops to 22°, and about 32 inches of snow falls in a normal winter. Milder January nights than 51% of U.S. towns; hotter July afternoons than 53% of U.S. towns.
How cold does it get in Caln Township in winter?
January nights average 22°. About 120 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 22°.
How much snow does Caln Township get?
About 32 inches in a normal winter at Coatesville 2 W, PA, most of it in February, with snow on the ground about 35 days a year.
How hot does it get in Caln Township?
July, with a typical high of 86° and a low of 65°. About 16 days a year reach 90° (Coatesville 2 W, PA).
When is the first and last frost in Caln Township?
In half of years the last spring frost (32°) comes by April 19 and the first fall frost by October 25, about 190 frost-free days, at Coatesville 2 W, PA.
What growing zone is Caln Township in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 1°.
What is the best time of year to visit Caln Township?
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 Caln Township getting warmer?
Yes: 1991–2020 averaged 1.8° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 81% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Caln Township.
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.