Mill Plain has chilly, snowy winters and warm summers, with plenty of rain
A typical July afternoon reaches 84°, a January night drops to 24°, and about 34 inches of snow falls in a normal winter.
A year in Mill Plain at a glance
Each month’s typical high and low, and what it brings.
What stands out about Mill Plain’s climate
Read from where Mill Plain sits among Connecticut’s towns. The page puts what stands out first.
Living with Mill Plain’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
216 frost-free days. The last frost comes by Apr 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 Nov 6.
About 34" a winter over 9 days with an inch or more, most in February. Snow covers the ground about 34 days a year.
Months averaging under 55° run from November through April. Heating is 84% of the year’s heating-and-cooling load.
About 9 days a year reach 90°, and July afternoons average 84°.
The nicest months are May, June, August, September and October. 0.0 miles of trails are waiting.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →What a year in Mill Plain feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Warmer than it used to be
The last 30 years in Mill Plain averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.5°).
A bigger shift than in 97% of U.S. towns.
Change by month
34 inches of snow, 49 of rain and melt
September is the wettest month and February the driest. Rain or snow falls on about 125 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
About 216 frost-free days a year
In half of years the last 32° night comes by April 5 and the first by November 6.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Mill Plain and its neighbors
Southport has the coldest January nights next door (24°) and Southport the hottest July afternoons (84°). Tap a town to see its climate.
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.
How Mill Plain compares
Against every U.S. town on TownTapestry, each counted once, with its place in Connecticut.
Mill Plain weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 40° | 24° | 3.6" | 8.5" | 11 | 11 | 23° – 38° |
| February | 41° | 25° | 3.1" | 10.7" | 10 | 12 | 20° – 39° |
| March | 49° | 31° | 4.3" | 7.0" | 11 | 6 | 34° – 48° |
| April | 60° | 41° | 4.3" | 0.9" | 11 | 0 | 46° – 55° |
| May | 70° | 50° | 3.9" | 0 | 12 | 0 | 56° – 64° |
| June | 79° | 60° | 4.4" | 0 | 11 | 0 | 66° – 72° |
| July | 84° | 66° | 3.9" | 0 | 9 | 0 | 71° – 78° |
| August | 83° | 65° | 4.0" | 0 | 9 | 0 | 70° – 78° |
| September | 76° | 58° | 4.6" | 0 | 8 | 0 | 64° – 71° |
| October | 65° | 47° | 4.5" | 0.1" | 10 | 0 | 52° – 62° |
| November | 54° | 37° | 3.8" | 0.9" | 9 | 0 | 41° – 50° |
| December | 44° | 29° | 4.5" | 5.5" | 12 | 5 | 30° – 48° |
| Year | 62° | 44° | 48.8" | 33.6" | 125 | 34 |
Heating and cooling a home in Mill Plain
84% of the work is heating, so the furnace matters far more than the air conditioner.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 20° to 39°. June is the most reliable, staying within 6°.
Common questions about Mill Plain’s climate
What is the coldest month in Mill Plain?
January, with a typical high of 40° and a low of 24°.
What is the hottest month in Mill Plain?
July, with a typical high of 84° and a low of 66°. About 9 days a year reach 90°.
How much snow does Mill Plain get?
About 34 inches in a normal winter, most of it in February.
When is the first frost in Mill Plain?
In half of years the first 32° night comes by November 6, and the last spring frost by April 5.
What is the rainiest month in Mill Plain?
September, with 4.6 inches of rain and melted snow. The year totals 49 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Mill Plain.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mill Plain itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Bridgeport Sikorsky Mem Airport, CT (7 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Today’s forecast: National Weather Service.