Cos Cob, CT Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Cos Cob, a community in Fairfield County, Connecticut.
This Afternoon
80°F
Sunny
Sunny. High near 80, with temperatures falling to around 78 in the afternoon. Northwest wind around 12 mph.
7-day forecast for Cos Cob
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 80°F | Sunny | 12 mph NW | 0% |
| Tonight | 53°F | Partly Cloudy | 6 to 9 mph N | 0% |
| Saturday | 70°F | Mostly Sunny | 5 to 8 mph NE | 0% |
| Saturday Night | 57°F | Partly Cloudy then Slight Chance Rain Showers | 6 mph SE | 16% |
| Sunday | 69°F | Rain Showers | 6 to 9 mph SE | 87% |
| Sunday Night | 59°F | Rain Showers | 7 to 10 mph NW | 87% |
| Monday | 68°F | Chance Rain Showers | 12 mph NE | 44% |
| Monday Night | 54°F | Chance Rain Showers | 9 to 14 mph NE | 48% |
| Tuesday | 64°F | Chance Rain Showers | 16 mph NE | 48% |
| Tuesday Night | 52°F | Chance Rain Showers | 17 mph NE | 37% |
| Wednesday | 65°F | Chance Rain Showers | 15 to 20 mph NE | 30% |
| Wednesday Night | 52°F | Chance Rain Showers | 15 to 20 mph NE | 35% |
| Thursday | 66°F | Chance Rain Showers | 16 mph NE | 35% |
| Thursday Night | 53°F | Chance Rain Showers | 10 to 15 mph NE | 35% |
Forecast source: National Weather Service (api.weather.gov) for Cos Cob (41.049, -73.592). Updated through the day.
Growing snapshot for Cos Cob
Last spring frost
Apr 17
First fall frost
Oct 23
Growing season
188 days
Hardiness zone
7a
More local growing data for Cos Cob: nearby ZIP 06807 weather · frost dates · planting calendar · Connecticut frost dates
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Climate data from the nearest NOAA station, Stamford 5 N, Ct (5.2 mi from Cos Cob). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 18, 2026.