Frost Advisory
Ends in 4 h 17 min
When
Until 9 AM EDT Saturday.
Where
In Connecticut, Southern Fairfield, Southern Middlesex, Southern New Haven, and Southern New London Counties. In New York, Southern Westchester County.
Issued for this forecast zone · National Weather Service Upton NY
What, impacts and precautionsHide details
What
Temperatures as low as the mid 30s will result in frost formation.
Impacts
Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered.
Precautionary actions
Take steps now to protect tender plants from the cold.
Areas: Southern Fairfield; Southern New Haven; Southern Middlesex; Southern New London; Southern Westchester
See it on weather.gov (opens in a new tab)

Observed 4:30 AM EDT at KHPN

New Canaan, CT weather

Clear and 41°5°.

Mostly agree

Now 41°5°

Clear · Feels like 37°3°

Wind: 6 mph9 km/h; From the west-northwest. 35–6 mph9 km/h through 4 PM
Dew point: 30°−1°; Dry, static shocks likely
UV index: 0Low; Moderate 11 AM–4 PM · peak 4
Air today: 50Good; EPA forecast · PM2.5 (fine particles)
Pressure: 30.48 inHg1032 hPa; Rising slowly · +0.03 inHg+0.9 hPa in 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

Good hours for

Low 36°2° today at 6 AM
Above 50°10° today by 11 AM
High 60°16° today at 2 PM
Below 50°10° tonight after 8 PM

TonightNear 38°3° · Clear
This morningUp to 54°12° by 11 AM · Mostly cloudy
This afternoonNear 58°14° · Mostly cloudy
TonightDown to 38°3° by 5 AM · Clear
Tomorrow morningUp to 57°14° by 11 AM · Clear
Tomorrow afternoonUp to 64°18° by 4 PM · Clear
Tomorrow nightDown to 41°5° by 3 AM · Clear

Hourly forecast, next 48 hours, in the place's local time
Hour	Conditions	Temperature	Feels like	Precipitation	Wind	Humidity	Cloud cover	UV index
Sat 4a	Mostly clear	38°3° (likely 38°3° to 42°6°)	38°3°	0%	3 mph5 km/h from N, gusts 9 mph15 km/h	85%	20%	0
Sat 5a	Partly cloudy	37°3° (likely 37°3° to 42°6°)	37°3°	0%	3 mph5 km/h from N, gusts 10 mph17 km/h	89%	28%	0
Sat 6a	Clear	36°2° (likely 36°2° to 41°5°)	36°2°	0%	3 mph5 km/h from N, gusts 10 mph16 km/h	92%	38%	0
Sat 7a	Sunny	36°2° (likely 36°2° to 41°5°)	36°2°	0%	3 mph5 km/h from N, gusts 10 mph16 km/h	92%	41%	0
Sat 8a	Cloudy	38°3° (likely 38°3° to 42°6°)	34°1°	0%	5 mph8 km/h from N, gusts 9 mph14 km/h	89%	71%	0
Sat 9a	Cloudy	42°6° (likely 42°6° to 46°8°)	42°6°	0%	3 mph5 km/h from N, gusts 6 mph10 km/h	82%	79%	1
Sat 10a	Cloudy	48°9° (likely 48°9° to 52°11°)	48°9°	0%	3 mph5 km/h from N, gusts 5 mph8 km/h	68%	81%	2
Sat 11a	Cloudy	54°12° (likely 52°11° to 56°13°)	54°12°	0%	3 mph5 km/h from N, gusts 6 mph10 km/h	54%	80%	3
Sat 12p	Cloudy	57°14° (likely 55°13° to 59°15°)	57°14°	0%	3 mph5 km/h from NW, gusts 7 mph11 km/h	47%	80%	3
Sat 1p	Cloudy	59°15° (likely 56°13° to 60°16°)	59°15°	0%	5 mph8 km/h from W, gusts 6 mph10 km/h	44%	80%	4
Sat 2p	Cloudy	60°16° (likely 57°14° to 61°16°)	60°16°	0%	5 mph8 km/h from W, gusts 7 mph11 km/h	42%	70%	4
Sat 3p	Cloudy	60°16° (likely 58°14° to 62°17°)	60°16°	0%	5 mph8 km/h from W, gusts 7 mph11 km/h	41%	65%	3
Sat 4p	Cloudy	60°16° (likely 58°14° to 62°17°)	60°16°	0%	3 mph5 km/h from W, gusts 7 mph11 km/h	42%	67%	2
Sat 5p	Mostly sunny	59°15° (likely 56°13° to 61°16°)	59°15°	0%	3 mph5 km/h from W, gusts 7 mph11 km/h	47%	65%	1
Sat 6p	Mostly clear	55°13° (likely 52°11° to 57°14°)	55°13°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	57%	56%	0
Sat 7p	Mostly clear	51°11° (likely 48°9° to 53°12°)	51°11°	0%	2 mph3 km/h from W, gusts 5 mph9 km/h	63%	46%	0
Sat 8p	Clear	48°9° (likely 46°8° to 52°11°)	48°9°	0%	1 mph2 km/h from NW, gusts 4 mph7 km/h	71%	40%	0
Sat 9p	Clear	46°8° (likely 45°7° to 51°11°)	46°8°	0%	1 mph2 km/h from NW, gusts 4 mph6 km/h	73%	32%	0
Sat 10p	Clear	44°7° (likely 44°7° to 50°10°)	44°7°	0%	1 mph2 km/h from NW, gusts 4 mph7 km/h	76%	0%	0
Sat 11p	Clear	42°6° (likely 42°6° to 49°9°)	42°6°	0%	1 mph2 km/h from NW, gusts 5 mph8 km/h	82%	0%	0
Sun 12a	Clear	41°5° (likely 41°5° to 47°8°)	41°5°	0%	1 mph2 km/h from NW, gusts 5 mph8 km/h	85%	0%	0
Sun 1a	Clear	41°5° (likely 41°5° to 45°7°)	41°5°	0%	2 mph3 km/h from NW, gusts 6 mph9 km/h	82%	0%	0
Sun 2a	Clear	40°4° (likely 40°4° to 44°7°)	40°4°	0%	2 mph3 km/h from NW, gusts 6 mph9 km/h	85%	5%	0
Sun 3a	Clear	39°4° (likely 39°4° to 43°6°)	39°4°	0%	2 mph3 km/h from NW, gusts 6 mph10 km/h	89%	9%	0
Sun 4a	Clear	39°4° (likely 39°4° to 43°6°)	39°4°	0%	3 mph5 km/h from NW, gusts 7 mph12 km/h	89%	10%	0
Sun 5a	Clear	38°3° (likely 38°3° to 43°6°)	38°3°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	89%	11%	0
Sun 6a	Clear	38°3° (likely 38°3° to 42°6°)	38°3°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	85%	10%	0
Sun 7a	Sunny	39°4° (likely 39°4° to 41°5°)	39°4°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	79%	9%	0
Sun 8a	Sunny	39°4° (likely 39°4° to 42°6°)	39°4°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	85%	9%	0
Sun 9a	Sunny	44°7° (likely 44°7° to 48°9°)	44°7°	0%	3 mph5 km/h from NW, gusts 7 mph12 km/h	76%	0%	1
Sun 10a	Sunny	52°11° (likely 52°11° to 55°13°)	52°11°	0%	2 mph3 km/h from NW, gusts 5 mph8 km/h	61%	0%	2
Sun 11a	Sunny	57°14° (likely 57°14° to 61°16°)	57°14°	0%	2 mph3 km/h from NW, gusts 4 mph7 km/h	53%	0%	3
Sun 12p	Sunny	59°15° (likely 59°15° to 63°17°)	59°15°	0%	3 mph5 km/h from W, gusts 5 mph9 km/h	47%	0%	4
Sun 1p	Sunny	62°17° (likely 62°17° to 65°18°)	62°17°	0%	3 mph5 km/h from W, gusts 4 mph7 km/h	43%	0%	4
Sun 2p	Sunny	63°17° (likely 63°17° to 66°19°)	63°17°	0%	3 mph5 km/h from W, gusts 5 mph8 km/h	41%	0%	4
Sun 3p	Sunny	63°17° (likely 62°17° to 66°19°)	63°17°	0%	3 mph5 km/h from W, gusts 6 mph10 km/h	41%	0%	3
Sun 4p	Sunny	64°18° (likely 62°17° to 66°19°)	64°18°	0%	3 mph5 km/h from SW, gusts 6 mph10 km/h	40%	0%	2
Sun 5p	Sunny	62°17° (likely 60°16° to 64°18°)	62°17°	0%	2 mph3 km/h from SW, gusts 7 mph11 km/h	44%	0%	1
Sun 6p	Clear	59°15° (likely 54°12° to 59°15°)	59°15°	0%	2 mph3 km/h from SW, gusts 7 mph11 km/h	49%	0%	0
Sun 7p	Clear	54°12° (likely 52°11° to 55°13°)	54°12°	0%	1 mph2 km/h from SW, gusts 8 mph13 km/h	61%	0%	0
Sun 8p	Clear	50°10° (likely 48°9° to 54°12°)	50°10°	0%	1 mph2 km/h from W, gusts 6 mph10 km/h	71%	0%	0
Sun 9p	Clear	48°9° (likely 45°7° to 52°11°)	48°9°	0%	1 mph2 km/h from W, gusts 8 mph13 km/h	77%	0%	0
Sun 10p	Clear	46°8° (likely 44°7° to 50°10°)	46°8°	0%	1 mph2 km/h from W, gusts 7 mph12 km/h	83%	0%	0
Sun 11p	Clear	45°7° (likely 43°6° to 49°9°)	45°7°	0%	2 mph3 km/h from W, gusts 7 mph12 km/h	82%	0%	0
Mon 12a	Clear	44°7° (likely 42°6° to 48°9°)	44°7°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	82%	0%	0
Mon 1a	Clear	43°6° (likely 41°5° to 48°9°)	43°6°	0%	3 mph5 km/h from W, gusts 7 mph11 km/h	86%	0%	0
Mon 2a	Clear	42°6° (likely 41°5° to 47°8°)	42°6°	0%	3 mph5 km/h from W, gusts 6 mph10 km/h	86%	0%	0
Mon 3a	Clear	41°5° (likely 39°4° to 46°8°)	41°5°	0%	3 mph5 km/h from W, gusts 5 mph7 km/h	89%	0%	0

Days ahead

Shaded: typical range for these dates (1991–2020)

Today, Oct 24. Cloudy. High 60°16°, low 36°2°. Typical 60°16° / 43°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 38°3°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 60°16°
  Dry
3. Evening
  6 PM–midnight
  Clear, 48°9°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 38°3°
  Dry
Official NWS forecast
Today: Areas of frost before 9am. Partly sunny, with a high near 60. Northwest wind around 5 mph.
Tonight: Areas of frost. Partly cloudy, with a low around 36. North wind around 3 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
58°14°–62°17°
Low, likely
36°2°–41°5°
Typical high / low
60°16° / 43°6°
Wind
7 mph11 km/h, gusts 15 mph23 km/h
UV peak
4
Tomorrow, Oct 25. Sunny. High 64°18°, low 39°4°. Typical 60°16° / 42°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 39°4°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 64°18°
  Dry
3. Evening
  6 PM–midnight
  Clear, 50°10°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 41°5°
  Dry
Official NWS forecast
Day: Areas of frost before 9am. Sunny. High near 64, with temperatures falling to around 62 in the afternoon. West wind around 3 mph.
Night: Clear. Low around 39, with temperatures rising to around 41 overnight. West wind around 3 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–66°19°
Low, likely
39°4°–41°5°
Typical high / low
60°16° / 42°6°
Wind
7 mph11 km/h, gusts 12 mph19 km/h
UV peak
4
Monday, Oct 26. Sunny. High 67°19°, low 44°7°. Typical 59°15° / 42°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 43°6°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 56°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 49°9°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Patchy frost before 8am. Sunny. High near 67, with temperatures falling to around 65 in the afternoon.
Night: Mostly clear, with a low around 44.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
66°19°–68°20°
Low, likely
40°4°–44°7°
Typical high / low
59°15° / 42°6°
Wind
8 mph13 km/h, gusts 15 mph23 km/h
UV peak
4
Tuesday, Oct 27. Sunny. High 57°14°, low 35°2°. Typical 59°15° / 42°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 57°14°
  Dry
3. Evening
  6 PM–midnight
  Clear, 46°8°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 40°4°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 57.
Night: Mostly clear, with a low around 35.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
56°13°–58°14°
Low, likely
35°2°–45°7°
Typical high / low
59°15° / 42°6°
Wind
11 mph18 km/h, gusts 29 mph47 km/h
UV peak
4
Wednesday, Oct 28. Partly sunny. High 57°14°, low 44°7°. Typical 59°15° / 42°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 39°4°
  Dry
2. Afternoon
  noon–6 PM
  Partly sunny, 55°13°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 48°9°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 45°7°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 57.
Night: Partly cloudy, with a low around 44.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
53°12°–58°14°
Low, likely
35°2°–44°7°
Typical high / low
59°15° / 42°6°
Wind
7 mph11 km/h, gusts 17 mph28 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 64°18°, low 49°9°. Typical 58°14° / 41°5°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 46°8°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 55°13°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 50°10°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 64.
Night: Partly cloudy, with a low around 49.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
59°15°–65°18°
Low, likely
41°5°–49°9°
Typical high / low
58°14° / 41°5°
Wind
11 mph18 km/h, gusts 30 mph49 km/h
UV peak
4
Friday, Oct 30. Partly sunny. High 66°19°, low 47°8°. Typical 58°14° / 41°5°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 56°13°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 47°8°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 66.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
63°17°–70°21°
Low, likely
45°7°–49°9°
Typical high / low
58°14° / 41°5°
Wind
11 mph17 km/h, gusts 30 mph48 km/h
UV peak
4
Saturday, Oct 31. Partly sunny. High 65°18°, low 46°8°. Typical 58°14° / 41°5°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 46°8°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 65°18°
  Dry
3. Evening
  6 PM–midnight
  Partly cloudy, 54°12°
  Dry
4. Overnight
  midnight–6 AM
  Partly cloudy, 48°9°
  Dry
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
59°15°–70°21°
Low, likely
44°7°–49°9°
Typical high / low
58°14° / 41°5°
Wind
8 mph13 km/h, gusts 26 mph42 km/h
UV peak
3
Sunday, Nov 1. Cloudy. High 63°17°, low 48°9°. Typical 57°14° / 40°4°. Rain 0.01 in0.3 mm, 20% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Drizzle, 56°13°
  20% chance
4. Overnight
  midnight–6 AM
  Drizzle, 55°13°
  20% chance
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
56°13°–67°19°
Low, likely
40°4°–54°12°
Typical high / low
57°14° / 40°4°
Wind
7 mph12 km/h, gusts 20 mph32 km/h
UV peak
3
Monday, Nov 2. Drizzle. High 66°19°, low 54°12°. Typical 57°14° / 40°4°. Rain 0.2 in5.1 mm, 30% chance. Mostly agree.
1. Morning
  6 AM–noon
  Drizzle, 58°14°
  30% chance · 0.02 in0.5 mm
2. Afternoon
  noon–6 PM
  Cloudy, 67°19°
  20% chance · 0.1 in2.4 mm
3. Evening
  6 PM–midnight
  Mostly clear, 57°14°
  20% chance · 0.12 in3.1 mm
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–67°19°
Low, likely
52°11°–57°14°
Typical high / low
57°14° / 40°4°
Wind
18 mph29 km/h, gusts 43 mph69 km/h
UV peak
2

10 days15 days30 days

The outlook

Today
Dry, high 60°, low 36°.
Tomorrow
Dry, high 64°, low 39°, warming up.
Monday
Dry, high 67°, low 44°, warming up.
Rest of week
Mostly dry, highs 57–66°.

Want the meteorologists’ reasoning? Read the NWS forecast discussion (OKX) (opens in a new tab)

What changed since yesterday

No meaningful changes from yesterday’s forecast.

Radar

Radar data: NOAA MRMS, rendered by forecast.blue

Radar loads when scrolled into view

Full-screen radar

Rivers

NOAA river gauges within 25 mi

Long Island Sound near Bridgeport Harbor (IN MLLW)

16 mi

Below flood stage

Level: 2.0 ft

Forecast peak 8.5 ft Sat 10 AM

Reading from Sat 3:06 AM · NWS gauge page

Housatonic River at Stevenson

24 mi

Below flood stage

Level: 2.6 ft
Flow: 506 cfs

Forecast peak 6.7 ft Sat 8 PM

Reading from Sat 2:30 AM · NWS gauge page

Rippowam River at Stamford

6.1 mi

Below flood stage

Level: 1.5 ft

Reading from Sat 2:45 AM · NWS gauge page

Long Island Sound at Stamford (IN MLLW)

7.7 mi

Below flood stage

Level: 2.1 ft

Reading from Sat 3 AM · NWS gauge page

For your home

What this week’s weather means for heating, cooling, pipes and fresh air.

Heating this week

About 69% less heating than a typical week.

This week 32Typical 102

Heating degree days, base 65°F

Heat-pump hours, next 7 days

h below 47°F: 24
h below 17°F: 0
h below 5°F: 0

47, 17 and 5°F are the test points heat pumps are rated at. About 16 hours are near freezing and damp, when outdoor units defrost more often.

Comfort

Dry air outside (dew point 30°F).

Open the windows?

Today, 2:00 PM–4:00 PM

Good stretch to open the windows.

Is this typical?

WESTCHESTER CO AP · official normals 1991–2020 · records 1948–2026

Oct 24, today vs a typical year

Today’s expected high is about typical for the date.

Last 7 days vs normal

On average 2°1° colder than normal (daily mean temperature).

−7°−4°SunOct 18
−2°−1°MonOct 19
—TueOct 20
±0°WedOct 21
+1°ThuOct 22
—FriOct 23
—SatOct 24

New Canaan weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 44 min; Losing 2 min 35 s a day; shortest Dec 21, 1 h 32 min less
Golden hour: 5:21–6:17 PM; Morning 6:58–7:54 AM
Blue hour: 6:17–6:28 PM; Morning 6:47–6:58 AM; first light 6:47 AM

Stars tonight? Poor

Clouds most of the night (about 29% cover).

Moon

Waxing gibbous

96% lit · growing

Today: sets 5:26 AM · rises 4:56 PM
Full moon: Oct 26
New moon: Nov 9

Looking north from New Canaan. The highest point on the skyline is about 9,400 ft, 66 mi away.Skyline from USGS elevation data, heights drawn up to 6× taller. Sky, sun and moon as they are now.

1 active weather alert

Frost Advisory

New Canaan, CT weather

Next 2 hours

Next 48 hours

Days ahead

The outlook

Today

Tomorrow

Monday

Rest of week

What changed since yesterday

Radar

Rivers

Long Island Sound near Bridgeport Harbor (IN MLLW)

Housatonic River at Stevenson

Rippowam River at Stamford

Long Island Sound at Stamford (IN MLLW)

For your home

Heating this week

Heat-pump hours, next 7 days

Comfort

Open the windows?

Is this typical?

Oct 24, today vs a typical year

Last 7 days vs normal

Sun & moon

Sun

Stars tonight? Poor

Moon