Frost Advisory
Ends in 4 h 21 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 4:15 AM EDT at KGON

Old Mystic, CT weather

Clear and 36°2°.

Mostly agree

Now 36°2°

Clear · Feels like 31°−1°

Wind: 6 mph9 km/h; From the north. Up to 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 quality: 38Good; Main pollutant: PM2.5 (fine particles)
Pressure: 30.49 inHg1033 hPa; Rising slowly · +0.02 inHg+0.8 hPa in 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

11°6° cooler than this time yesterday (46°8° then, 35°2° now)

Good hours for

Low 34°1° today at 7 AM
Above 50°10° today by 10 AM
High 60°16° today at 2 PM
Below 50°10° tonight after 8 PM

TonightNear 36°2° · Clear
This morningUp to 56°13° by 11 AM · Partly cloudy
This afternoonNear 59°15° · Partly cloudy
TonightDown to 35°2° by 4 AM · Clear
Tomorrow morningUp to 56°13° by 11 AM · Clear
Tomorrow afternoonNear 59°15° · Clear
Tomorrow nightDown to 42°6° 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	Clear	36°2° (likely 31°−1° to 37°3°)	36°2°	0%	2 mph3 km/h from N, gusts 7 mph11 km/h	92%	0%	0
Sat 5a	Clear	36°2° (likely 31°−1° to 36°2°)	36°2°	0%	3 mph5 km/h from N, gusts 8 mph13 km/h	89%	3%	0
Sat 6a	Partly cloudy	35°2° (likely 30°−1° to 35°2°)	35°2°	0%	3 mph5 km/h from N, gusts 8 mph13 km/h	89%	22%	0
Sat 7a	Partly sunny	34°1° (likely 30°−1° to 35°2°)	34°1°	0%	3 mph5 km/h from N, gusts 8 mph13 km/h	92%	33%	0
Sat 8a	Sunny	36°2° (likely 32°0° to 36°2°)	36°2°	0%	3 mph5 km/h from N, gusts 8 mph13 km/h	92%	39%	0
Sat 9a	Sunny	42°6° (likely 39°4° to 42°6°)	42°6°	0%	2 mph3 km/h from N, gusts 7 mph11 km/h	82%	39%	1
Sat 10a	Partly sunny	50°10° (likely 45°7° to 50°10°)	50°10°	0%	2 mph3 km/h from N, gusts 6 mph10 km/h	63%	22%	2
Sat 11a	Partly sunny	56°13° (likely 50°10° to 56°13°)	56°13°	0%	3 mph5 km/h from NW, gusts 7 mph11 km/h	49%	48%	3
Sat 12p	Partly sunny	59°15° (likely 54°12° to 59°15°)	59°15°	0%	3 mph5 km/h from NW, gusts 11 mph17 km/h	42%	50%	4
Sat 1p	Partly sunny	59°15° (likely 57°14° to 60°16°)	59°15°	0%	5 mph8 km/h from NW, gusts 11 mph17 km/h	42%	50%	4
Sat 2p	Partly sunny	60°16° (likely 59°15° to 62°17°)	60°16°	0%	5 mph8 km/h from W, gusts 10 mph16 km/h	42%	50%	4
Sat 3p	Mostly sunny	60°16° (likely 60°16° to 62°17°)	60°16°	0%	5 mph8 km/h from W, gusts 9 mph15 km/h	44%	47%	3
Sat 4p	Mostly sunny	59°15° (likely 59°15° to 61°16°)	59°15°	0%	5 mph8 km/h from W, gusts 8 mph13 km/h	45%	23%	2
Sat 5p	Mostly sunny	58°14° (likely 57°14° to 60°16°)	58°14°	0%	3 mph5 km/h from W, gusts 6 mph10 km/h	51%	18%	1
Sat 6p	Clear	54°12° (likely 51°11° to 54°12°)	54°12°	0%	2 mph3 km/h from W, gusts 6 mph10 km/h	59%	14%	0
Sat 7p	Clear	50°10° (likely 47°8° to 50°10°)	50°10°	0%	1 mph2 km/h from W, gusts 6 mph9 km/h	66%	2%	0
Sat 8p	Clear	47°8° (likely 45°7° to 47°8°)	47°8°	0%	1 mph2 km/h from NW, gusts 5 mph8 km/h	74%	2%	0
Sat 9p	Clear	45°7° (likely 43°6° to 45°7°)	45°7°	0%	0 mph0 km/h, gusts 5 mph8 km/h	76%	0%	0
Sat 10p	Clear	42°6° (likely 42°6° to 44°7°)	42°6°	0%	0 mph0 km/h, gusts 6 mph10 km/h	86%	0%	0
Sat 11p	Clear	41°5° (likely 41°5° to 43°6°)	41°5°	0%	0 mph0 km/h, gusts 5 mph8 km/h	85%	0%	0
Sun 12a	Clear	40°4° (likely 40°4° to 42°6°)	40°4°	0%	1 mph2 km/h from NW, gusts 5 mph8 km/h	89%	0%	0
Sun 1a	Clear	39°4° (likely 39°4° to 41°5°)	39°4°	0%	1 mph2 km/h from N, gusts 5 mph8 km/h	92%	0%	0
Sun 2a	Clear	37°3° (likely 37°3° to 40°4°)	37°3°	0%	1 mph2 km/h from N, gusts 6 mph10 km/h	96%	0%	0
Sun 3a	Clear	36°2° (likely 36°2° to 40°4°)	36°2°	0%	1 mph2 km/h from N, gusts 7 mph11 km/h	100%	0%	0
Sun 4a	Clear	35°2° (likely 35°2° to 39°4°)	35°2°	0%	2 mph3 km/h from N, gusts 6 mph10 km/h	100%	0%	0
Sun 5a	Clear	35°2° (likely 35°2° to 38°3°)	35°2°	0%	2 mph3 km/h from N, gusts 7 mph11 km/h	100%	0%	0
Sun 6a	Clear	35°2° (likely 35°2° to 37°3°)	35°2°	0%	2 mph3 km/h from N, gusts 7 mph11 km/h	92%	0%	0
Sun 7a	Sunny	35°2° (likely 35°2° to 36°2°)	35°2°	0%	2 mph3 km/h from N, gusts 7 mph12 km/h	92%	0%	0
Sun 8a	Sunny	36°2° (likely 36°2° to 38°3°)	36°2°	0%	2 mph3 km/h from N, gusts 7 mph11 km/h	92%	0%	0
Sun 9a	Sunny	42°6° (likely 42°6° to 46°8°)	42°6°	0%	2 mph3 km/h from N, gusts 6 mph10 km/h	82%	0%	1
Sun 10a	Sunny	51°11° (likely 51°11° to 52°11°)	51°11°	0%	2 mph3 km/h from NW, gusts 5 mph8 km/h	61%	0%	2
Sun 11a	Sunny	56°13° (likely 56°13° to 58°14°)	56°13°	0%	1 mph2 km/h from NW, gusts 4 mph7 km/h	53%	0%	3
Sun 12p	Sunny	60°16° (likely 60°16° to 62°17°)	60°16°	0%	2 mph3 km/h from W, gusts 6 mph9 km/h	46%	0%	4
Sun 1p	Sunny	61°16° (likely 61°16° to 64°18°)	61°16°	0%	3 mph5 km/h from SW, gusts 7 mph11 km/h	46%	0%	4
Sun 2p	Sunny	61°16° (likely 61°16° to 65°18°)	61°16°	0%	5 mph8 km/h from SW, gusts 5 mph8 km/h	48%	0%	4
Sun 3p	Sunny	62°17° (likely 62°17° to 64°18°)	62°17°	0%	5 mph8 km/h from SW, gusts 8 mph14 km/h	46%	0%	3
Sun 4p	Sunny	60°16° (likely 60°16° to 62°17°)	60°16°	0%	5 mph8 km/h from SW, gusts 8 mph14 km/h	49%	0%	2
Sun 5p	Sunny	58°14° (likely 58°14° to 59°15°)	58°14°	0%	3 mph5 km/h from SW, gusts 9 mph15 km/h	55%	0%	1
Sun 6p	Clear	55°13° (likely 52°11° to 55°13°)	55°13°	0%	2 mph3 km/h from SW, gusts 10 mph16 km/h	61%	0%	0
Sun 7p	Clear	50°10° (likely 49°9° to 50°10°)	50°10°	0%	2 mph3 km/h from SW, gusts 10 mph15 km/h	77%	0%	0
Sun 8p	Clear	48°9° (likely 47°8° to 49°9°)	48°9°	0%	1 mph2 km/h from SW, gusts 9 mph15 km/h	83%	0%	0
Sun 9p	Clear	46°8° (likely 45°7° to 48°9°)	46°8°	0%	1 mph2 km/h from SW, gusts 9 mph15 km/h	89%	0%	0
Sun 10p	Clear	45°7° (likely 44°7° to 48°9°)	45°7°	0%	1 mph2 km/h from SW, gusts 9 mph15 km/h	89%	0%	0
Sun 11p	Clear	44°7° (likely 43°6° to 48°9°)	44°7°	0%	1 mph2 km/h from SW, gusts 9 mph15 km/h	93%	0%	0
Mon 12a	Clear	44°7° (likely 43°6° to 47°8°)	44°7°	0%	1 mph2 km/h from W, gusts 9 mph14 km/h	89%	0%	0
Mon 1a	Clear	43°6° (likely 42°6° to 46°8°)	43°6°	0%	2 mph3 km/h from W, gusts 9 mph14 km/h	89%	0%	0
Mon 2a	Clear	43°6° (likely 42°6° to 46°8°)	43°6°	0%	2 mph3 km/h from W, gusts 8 mph14 km/h	89%	0%	0
Mon 3a	Clear	42°6° (likely 42°6° to 46°8°)	42°6°	0%	2 mph3 km/h from W, gusts 4 mph7 km/h	89%	0%	0

Days ahead

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

Today, Oct 24. Cloudy. High 61°16°, low 34°1°. Typical 61°16° / 41°5°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 36°2°
  Dry
2. Afternoon
  noon–6 PM
  Mostly sunny, 60°16°
  Dry
3. Evening
  6 PM–midnight
  Clear, 47°8°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 35°2°
  Dry
Official NWS forecast
Today: Areas of frost before 9am. Mostly sunny. High near 61, with temperatures falling to around 58 in the afternoon. Northwest wind around 5 mph.
Tonight: Areas of frost. Mostly clear. Low around 34, with temperatures rising to around 36 overnight. North wind around 3 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
60°16°–62°17°
Low, likely
30°−1°–35°2°
Typical high / low
61°16° / 41°5°
Wind
6 mph10 km/h, gusts 12 mph19 km/h
UV peak
4
Tomorrow, Oct 25. Sunny. High 63°17°, low 36°2°. Typical 61°16° / 40°4°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 36°2°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 48°9°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 42°6°
  Dry
Official NWS forecast
Day: Areas of frost before 9am. Sunny. High near 63, with temperatures falling to around 58 in the afternoon. Northwest wind 1 to 5 mph.
Night: Clear. Low around 36, with temperatures rising to around 41 overnight. West wind around 3 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
63°17°–65°18°
Low, likely
35°2°–36°2°
Typical high / low
61°16° / 40°4°
Wind
7 mph10 km/h, gusts 15 mph24 km/h
UV peak
4
Monday, Oct 26. Sunny. High 67°19°, low 43°6°. Typical 60°16° / 40°4°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 43°6°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 67°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 54°12°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 48°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 64 in the afternoon.
Night: Clear, with a low around 43.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
65°18°–68°20°
Low, likely
40°4°–43°6°
Typical high / low
60°16° / 40°4°
Wind
8 mph13 km/h, gusts 23 mph36 km/h
UV peak
4
Tuesday, Oct 27. Sunny. High 57°14°, low 32°0°. Typical 60°16° / 40°4°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 45°7°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 55°13°
  Dry
3. Evening
  6 PM–midnight
  Clear, 43°6°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 34°1°
  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 32.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
54°12°–57°14°
Low, likely
32°0°–43°6°
Typical high / low
60°16° / 40°4°
Wind
9 mph15 km/h, gusts 27 mph43 km/h
UV peak
4
Wednesday, Oct 28. Mostly sunny. High 56°13°, low 41°5°. Typical 60°16° / 39°4°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 34°1°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 54°12°
  Dry
3. Evening
  6 PM–midnight
  Mostly clear, 43°6°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 42°6°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 56.
Night: Partly cloudy, with a low around 41.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
53°12°–56°13°
Low, likely
28°−2°–41°5°
Typical high / low
60°16° / 39°4°
Wind
7 mph11 km/h, gusts 15 mph24 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 63°17°, low 49°9°. Typical 59°15° / 39°4°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 44°7°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 60°16°
  Dry
3. Evening
  6 PM–midnight
  Clear, 52°11°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 49°10°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 63.
Night: Partly cloudy, with a low around 49.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
58°14°–63°17°
Low, likely
38°3°–49°9°
Typical high / low
59°15° / 39°4°
Wind
11 mph17 km/h, gusts 32 mph52 km/h
UV peak
4
Friday, Oct 30. Partly sunny. High 66°19°, low 48°9°. Typical 59°15° / 39°4°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 49°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 55°13°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 46°8°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 66.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
64°18°–69°21°
Low, likely
46°8°–50°10°
Typical high / low
59°15° / 39°4°
Wind
9 mph15 km/h, gusts 29 mph47 km/h
UV peak
4
Saturday, Oct 31. Partly sunny. High 64°18°, low 44°7°. Typical 58°14° / 38°3°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 45°7°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 64°18°
  Dry
3. Evening
  6 PM–midnight
  Partly cloudy, 50°10°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 46°8°
  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
58°14°–69°21°
Low, likely
38°3°–48°9°
Typical high / low
58°14° / 38°3°
Wind
11 mph17 km/h, gusts 27 mph44 km/h
UV peak
4
Sunday, Nov 1. Cloudy. High 62°17°, low 47°8°. Typical 58°14° / 38°3°. Rain, 20% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Partly sunny, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 61°16°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 54°12°
  20% chance
4. Overnight
  midnight–6 AM
  Cloudy, 55°13°
  30% 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
54°12°–65°18°
Low, likely
35°2°–54°12°
Typical high / low
58°14° / 38°3°
Wind
8 mph13 km/h, gusts 21 mph34 km/h
UV peak
3
Monday, Nov 2. Cloudy. High 64°18°, low 55°13°. Typical 58°14° / 38°3°. Rain 0.06 in1.5 mm, 30% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 58°15°
  30% chance
2. Afternoon
  noon–6 PM
  Cloudy, 65°18°
  30% chance · 0.01 in0.4 mm
3. Evening
  6 PM–midnight
  Mostly clear, 57°14°
  30% chance · 0.2 in5.1 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.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
58°14°–69°21°
Low, likely
51°11°–57°14°
Typical high / low
58°14° / 38°3°
Wind
15 mph24 km/h, gusts 33 mph54 km/h
UV peak
2

10 days15 days30 days

The outlook

Today
Dry, high 61°, low 34°.
Tomorrow
Dry, high 63°, low 36°.
Monday
Dry, high 67°, low 43°, warming up.
Rest of week
Mostly dry, highs 56–66°.

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 New London Harbor (IN MLLW)

5.9 mi

Below flood stage

Level: 1.5 ft

Forecast peak 4.3 ft Sat 9 AM

Reading from Sat 3 AM · NWS gauge page

Pawcatuck at Westerly

8.0 mi

Below flood stage

Level: 4.4 ft
Flow: 417 cfs

Forecast peak 4.4 ft Sat 8 AM

Reading from Sat 2 AM · NWS gauge page

Atlantic Coast at Watch Hill Cove (IN MLLW)

8.3 mi

Below flood stage

Level: 1.2 ft

Forecast peak 3.9 ft Sat 8 AM

Reading from Sat 2 AM · NWS gauge page

Yantic River at Yantic

14 mi

Below flood stage

Level: 2.0 ft
Flow: 90 cfs

Forecast peak 2.0 ft Sat 8 AM

Reading from Sat 2:45 AM · NWS gauge page

For your home

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

Heating this week

About 67% less heating than a typical week.

This week 35Typical 106

Heating degree days, base 65°F

Heat-pump hours, next 7 days

h below 47°F: 26
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 18 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–3:00 PM

Good stretch to open the windows.

Is this typical?

NORWICH PUBLIC UTILITY PLANT · official normals 1991–2020 · records 1956–2026

Oct 24, today vs a typical year

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

Last 7 days vs normal

On average 3°2° colder than normal (daily mean temperature).

−12°−7°SunOct 18
−7°−4°MonOct 19
−2°−1°TueOct 20
+2°+1°WedOct 21
—ThuOct 22
+4°+2°FriOct 23
—SatOct 24

Old Mystic weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 43 min; Losing 2 min 35 s a day; shortest Dec 21, 1 h 33 min less
Golden hour: 5:15–6:10 PM; Morning 6:52–7:48 AM
Blue hour: 6:10–6:21 PM; Morning 6:41–6:52 AM; first light 6:41 AM

Stars tonight? Good

Clear 4:39–6:41 AM; moon 96% lit, sets 5:20 AM.

Moon

Waxing gibbous

96% lit · growing

Today: sets 5:20 AM · rises 4:50 PM
Full moon: Oct 26
New moon: Nov 9

Looking south from Old Mystic. The highest point on the skyline is about 1,000 ft, 21 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

Old Mystic, 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 New London Harbor (IN MLLW)

Pawcatuck at Westerly

Atlantic Coast at Watch Hill Cove (IN MLLW)

Yantic River at Yantic

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? Good

Moon