No extremes in Old Greenwich: its weather tracks the middle of U.S. towns
Midsummer highs settle at about 85°. It is a wet place: more rain and snow fall here than on 71% of U.S. towns. Compared with 1901–2000, the average now sits 2.2° higher. Central heating does most of its work from November to March, in months below 50° on average.
A year in Old Greenwich at a glance
Each month’s typical high and low, and what it brings.
What stands out about Old Greenwich’s climate
Compared with towns across the U.S., with Old Greenwich’s place in Connecticut beside it.
What a year in Old Greenwich feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 200 frost-free days a year
In half of years the last 32° night comes by April 12 and the first by October 31. Frost and day counts come from NOAA’s station at Westchester Co Airport, 8 miles from the town’s center, 370 ft higher.
The 2023 USDA map puts Old Greenwich’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 6°. 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 34 inches of snow a winter
Snow, measured at Stamford 5 N, CT, falls mostly in February. Precipitation (rain plus melted snow) adds up to 47 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 124 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Old Greenwich
87% of the work is heating, so the furnace matters far more than the air conditioner. 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 Westchester Co Airport.
Living with Old Greenwich’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
200 frost-free days in zone 7b. The last frost comes by Apr 12 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 31.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 5.9 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Old Greenwich from natural hazards, river flooding is the largest share (40%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Old Greenwich and its neighbors
Greenwich has the coldest January nights next door (23°, 2° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Old Greenwich’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 |
|---|---|---|---|---|
| Old Greenwich, CT | 25° | 85° | 47" | 34" |
| Mount Airy, MD | 24° | 85° | 46" | 31" |
| New Martinsville, WV | 22° | 85° | 46" | 27" |
| New Freedom, PA | 21° | 84° | 48" | 29" |
| Erlanger, KY | 23° | 85° | 47" | 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 Old Greenwich averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.7°).
A bigger shift than in 97% 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 Old Greenwich compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Old Greenwich’s place among Connecticut’s.
Old Greenwich weather by month
Highs, lows and precipitation from NOAA’s grid at Old Greenwich’s center; snow, wet days and snow on the ground from Stamford 5 N, CT. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 40° | 25° | 3.4" | 9.1" | 11 | 24° – 39° |
| February | 42° | 26° | 2.9" | 11.9" | 8 | 21° – 40° |
| March | 49° | 32° | 4.1" | 5.9" | 10 | 35° – 49° |
| April | 61° | 42° | 4.0" | 0.5" | 12 | 47° – 56° |
| May | 70° | 51° | 3.9" | 0.0" | 12 | 57° – 65° |
| June | 79° | 61° | 4.3" | 0.0" | 12 | 67° – 73° |
| July | 85° | 67° | 4.2" | 0.0" | 9 | 71° – 79° |
| August | 83° | 66° | 4.1" | 0.0" | 9 | 70° – 78° |
| September | 76° | 59° | 4.5" | 0.0" | 9 | 65° – 72° |
| October | 65° | 47° | 4.4" | 0.0" | 10 | 52° – 64° |
| November | 54° | 38° | 3.5" | 0.8" | 10 | 41° – 51° |
| December | 45° | 30° | 4.0" | 5.8" | 11 | 30° – 49° |
| Year | 62° | 45° | 47.1" | 34.0" | 124 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 21° to 40°. June is the most reliable, staying within 6°.
Where Old Greenwich’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 Old Greenwich’s center.
- Snow: Stamford 5 N, CT.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Westchester Co Airport, 8 miles from the town’s center, 370 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 Old Greenwich’s climate
What is the weather like in Old Greenwich?
A typical July afternoon reaches 85°, a January night drops to 25°, and about 34 inches of snow falls in a normal winter. Milder January nights than 62% of U.S. towns; cooler July afternoons than 52% of U.S. towns.
How cold does it get in Old Greenwich in winter?
January nights average 25°. About 105 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.
How much snow does Old Greenwich get?
About 34 inches in a normal winter at Stamford 5 N, CT, most of it in February.
How hot does it get in Old Greenwich?
July, with a typical high of 85° and a low of 67°. About 10 days a year reach 90° (Westchester Co Airport).
When is the first and last frost in Old Greenwich?
In half of years the last spring frost (32°) comes by April 12 and the first fall frost by October 31, about 200 frost-free days, at Westchester Co Airport.
What growing zone is Old Greenwich in?
Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 6°.
What is the best time of year to visit Old Greenwich?
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 Old Greenwich getting warmer?
Yes: 1991–2020 averaged 2.2° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 97% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Old Greenwich.
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.