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Old Lyme, CT Weather Forecast

Lower Connecticut River Valley Planning Region, Connecticut

7-day view
Conditions now · Sun, 11:15 PM EDT
70°FDewpoint 70°FRain likely

Measured at KSNC · Chester Arpt, CT · airport · 11 mi away · 22 minutes ago

Old Lyme, CT at Sun, 11:15 PM EDT: 70°F and rain likely, measured at KSNC (Chester Arpt, CT) 11 mi away, 22 minutes ago. Rest of today: high 75°F, low 69°F, 100% chance of rain. 1 active National Weather Service alert: Special Weather Statement.

Current radarNational Weather Service radar · alerts refresh every minuteOpen live map →
Rain: light → heavyRadar mosaic © Iowa Environmental Mesonet / NWS · Basemap © OpenStreetMap contributors, © Protomaps
Hour by hourTemperatureChance of rain
12 PMRain likely73°F100%
1 PMRain likely73°F89%
2 PMRain likely73°F78%
3 PMScattered rain74°F47%
4 PMMostly cloudy74°F16%
5 PMMostly cloudy75°F8%
6 PMPartly cloudy74°F4%
7 PMPartly cloudy72°F2%
8 PMPartly cloudy71°F0%
9 PMMostly sunny70°F0%
10 PMMostly sunny69°F0%
11 PMPartly cloudy69°F0%

Seven-day outlook

52–76°F across the week
TodaySep 13Rain likely · 100% chance of rain69°F / 75°F
MonSep 14Scattered rain · 31% chance of rain58°F / 72°F
TueSep 15Clear · 0% chance of rain52°F / 69°F
WedSep 16Mostly sunny · 0% chance of rain56°F / 72°F
ThuSep 17Partly cloudy · 4% chance of rain62°F / 76°F
FriSep 18Partly cloudy · 16% chance of rain63°F / 75°F
SatSep 19Partly cloudy · 16% chance of rain59°F / 72°F
SunSep 20Scattered rain · 33% chance of rain60°F / 69°F

Forecasts come from the National Weather Service's own computer models, and current conditions from the nearest reporting weather station. Both are served through the weather API. A forecast is guidance, not a warning, and anything the Weather Service has actually issued is on the live map.

About the Old Lyme forecast

Old Lyme sits at 41.3123°N, 72.3057°W in Lower Connecticut River Valley Planning Region, Connecticut. The forecast above is drawn for that point from the National Weather Service's own computer models: a seven-day outlook, and a finer-grained one covering the next eighteen hours where it reaches, and the radar and alert panels show what the Weather Service has out over the area right now.

County
Lower Connecticut River Valley Planning Region
Coordinates
41.3123°N, 72.3057°W
Population
7,696 · 2023 estimate
Land area
23.014 sq mi

Place data from the US Census Bureau. Coordinates are the Census internal point for Old Lyme, and the forecast is for that location, not for every address inside the city limits, and a large city can have real weather differences from one side to the other.

How well can the network see Old Lyme?

The nearest Doppler radar is KOKX (New York City, NY), 42 miles to the SW. A WSR-88D's lowest routine scan sits half a degree above horizontal, and the earth curves away beneath it, so by the time that beam reaches Old Lyme its centre is about 2,900 ft above ground. That is comfortably inside the useful range. The lowest scan passes low enough over Old Lyme to show rotation in the part of a storm where tornadoes actually form. Old Lyme is closer to its radar than 52% of US cities.

The closest instrument actually measuring the air is KSNC · Chester Arpt on the ASOS/AWOS network, 11 miles away. Near enough to be representative on most days, though a summer thunderstorm can soak one and miss the other entirely.

Beam height is the standard 4/3-earth approximation for the 0.5° scan and assumes normal refraction; it is where the centre of the beam is, not its edges, and unusual temperature profiles bend it. Radar siting from the NWS WSR-88D network, station positions from the Connecticut observing network as of this build.

Forecasts near Old Lyme

Elsewhere in Connecticut

Bridgeport · Stamford · New Haven · Hartford · Waterbury · Norwalk · All Connecticut forecasts →