Frost Advisory
Ends in 5 h 34 min
When
From midnight tonight to 9 AM EDT Saturday.
Where
Portions of central, northern, and southern New Jersey and southeast Pennsylvania.
Issued for this forecast zone · National Weather Service Mount Holly NJ
What, impacts and precautionsHide details
What
Temperatures as low as 33 degrees 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: Middlesex; Western Monmouth; Mercer; Salem; Gloucester; Camden; Northwestern Burlington; Ocean; Cumberland; Atlantic; Southeastern Burlington; Delaware; Philadelphia; Eastern Chester; Eastern Montgomery; Lower Bucks
See it on weather.gov (opens in a new tab)

Observed 3:00 AM EDT at KPHL

Merion Station, PA weather

Clear and 45°7°.

Mostly agree

Now 45°7°

Clear

Wind: 5 mph7 km/h; From the north-northwest. Up to 5 mph8 km/h through 3 PM
Dew point: 37°3°; Comfortable
UV index: 0Low; Moderate 11 AM–4 PM · peak 4
Air quality: 63Moderate; Main pollutant: PM2.5 (fine particles)
Pressure: 30.49 inHg1033 hPa; Steady over the last 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

12°7° cooler than this time yesterday (55°13° then, 43°6° now)

Good hours for

Low 36°2° today at 6 AM
Above 50°10° today by 10 AM
High 63°17° today at 4 PM
Below 50°10° tonight after 9 PM

TonightNear 38°3° · Clear
This morningUp to 55°13° by 11 AM · Clear
This afternoonUp to 63°17° by 4 PM · Clear
TonightDown to 36°2° by 4 AM · Clear
Tomorrow morningUp to 56°13° by 11 AM · Clear
Tomorrow afternoonUp to 65°18° by 4 PM · Clear
Tomorrow nightDown to 43°6° by 2 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 3a	Clear	38°3° (likely 38°3° to 42°6°)	38°3°	0%	0 mph0 km/h, gusts 3 mph6 km/h	89%	2%	0
Sat 4a	Clear	38°3° (likely 38°3° to 41°5°)	38°3°	0%	5 mph8 km/h from N, gusts 5 mph7 km/h	92%	5%	0
Sat 5a	Clear	38°3° (likely 37°3° to 40°4°)	36°2°	0%	5 mph8 km/h from N, gusts 5 mph8 km/h	89%	8%	0
Sat 6a	Mostly clear	36°2° (likely 36°2° to 39°4°)	33°1°	0%	5 mph8 km/h from N, gusts 6 mph10 km/h	96%	22%	0
Sat 7a	Mostly sunny	37°3° (likely 36°2° to 38°3°)	34°1°	0%	5 mph8 km/h from N, gusts 7 mph11 km/h	92%	25%	0
Sat 8a	Sunny	39°4° (likely 37°3° to 39°4°)	36°2°	0%	5 mph8 km/h from N, gusts 7 mph12 km/h	85%	22%	0
Sat 9a	Sunny	44°7° (likely 41°5° to 44°7°)	42°6°	0%	5 mph8 km/h from N, gusts 8 mph12 km/h	73%	19%	1
Sat 10a	Sunny	51°11° (likely 46°8° to 51°11°)	51°11°	0%	5 mph8 km/h from N, gusts 7 mph11 km/h	59%	19%	2
Sat 11a	Sunny	55°13° (likely 51°11° to 56°13°)	55°13°	0%	5 mph8 km/h from NE, gusts 5 mph8 km/h	53%	10%	3
Sat 12p	Sunny	58°14° (likely 55°13° to 60°16°)	58°14°	0%	0 mph0 km/h, gusts 4 mph6 km/h	45%	4%	4
Sat 1p	Sunny	61°16° (likely 58°14° to 61°16°)	61°16°	0%	0 mph0 km/h, gusts 4 mph6 km/h	39%	7%	4
Sat 2p	Sunny	62°17° (likely 59°15° to 62°17°)	62°17°	0%	0 mph0 km/h, gusts 3 mph5 km/h	36%	10%	4
Sat 3p	Sunny	62°17° (likely 60°16° to 63°17°)	62°17°	0%	0 mph0 km/h, gusts 2 mph4 km/h	35%	8%	3
Sat 4p	Sunny	63°17° (likely 60°16° to 63°17°)	63°17°	0%	0 mph0 km/h, gusts 2 mph3 km/h	34%	4%	2
Sat 5p	Sunny	62°17° (likely 59°15° to 62°17°)	62°17°	0%	0 mph0 km/h, gusts 2 mph4 km/h	36%	1%	1
Sat 6p	Clear	60°16° (likely 55°13° to 60°16°)	60°16°	0%	0 mph0 km/h, gusts 4 mph6 km/h	41%	0%	0
Sat 7p	Clear	57°14° (likely 51°11° to 57°14°)	57°14°	0%	0 mph0 km/h, gusts 4 mph7 km/h	45%	0%	0
Sat 8p	Clear	50°10° (likely 50°10° to 53°12°)	50°10°	0%	0 mph0 km/h, gusts 3 mph5 km/h	61%	0%	0
Sat 9p	Clear	47°8° (likely 47°8° to 51°11°)	47°8°	0%	0 mph0 km/h, gusts 4 mph6 km/h	74%	0%	0
Sat 10p	Clear	45°7° (likely 45°7° to 49°9°)	45°7°	0%	0 mph0 km/h, gusts 5 mph9 km/h	79%	0%	0
Sat 11p	Clear	43°6° (likely 43°6° to 47°8°)	43°6°	0%	0 mph0 km/h, gusts 5 mph8 km/h	86%	0%	0
Sun 12a	Clear	40°4° (likely 40°4° to 46°8°)	40°4°	0%	0 mph0 km/h, gusts 5 mph8 km/h	96%	0%	0
Sun 1a	Clear	39°4° (likely 39°4° to 45°7°)	39°4°	0%	0 mph0 km/h, gusts 5 mph9 km/h	100%	0%	0
Sun 2a	Clear	38°3° (likely 38°3° to 45°7°)	38°3°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	0%	0
Sun 3a	Clear	37°3° (likely 36°2° to 44°7°)	37°3°	0%	0 mph0 km/h, gusts 4 mph6 km/h	100%	0%	0
Sun 4a	Clear	36°2° (likely 35°2° to 43°6°)	36°2°	0%	0 mph0 km/h, gusts 4 mph7 km/h	100%	0%	0
Sun 5a	Clear	36°2° (likely 35°2° to 42°6°)	36°2°	0%	0 mph0 km/h, gusts 5 mph7 km/h	100%	0%	0
Sun 6a	Clear	35°2° (likely 35°2° to 41°5°)	35°2°	0%	0 mph0 km/h, gusts 5 mph8 km/h	100%	0%	0
Sun 7a	Sunny	35°2° (likely 35°2° to 40°4°)	35°2°	0%	0 mph0 km/h, gusts 6 mph10 km/h	100%	1%	0
Sun 8a	Sunny	37°3° (likely 36°2° to 41°5°)	34°1°	0%	5 mph8 km/h from NW, gusts 6 mph10 km/h	100%	1%	0
Sun 9a	Sunny	42°6° (likely 42°6° to 47°8°)	42°6°	0%	0 mph0 km/h, gusts 6 mph9 km/h	89%	0%	1
Sun 10a	Sunny	49°9° (likely 49°9° to 52°11°)	49°9°	0%	0 mph0 km/h, gusts 5 mph8 km/h	68%	2%	2
Sun 11a	Sunny	56°13° (likely 56°13° to 58°14°)	56°13°	0%	0 mph0 km/h, gusts 6 mph9 km/h	57%	4%	3
Sun 12p	Sunny	60°16° (likely 59°15° to 62°17°)	60°16°	0%	0 mph0 km/h, gusts 6 mph9 km/h	47%	6%	4
Sun 1p	Sunny	62°17° (likely 60°16° to 64°18°)	62°17°	0%	0 mph0 km/h, gusts 5 mph8 km/h	44%	4%	4
Sun 2p	Sunny	63°17° (likely 62°17° to 65°18°)	63°17°	0%	0 mph0 km/h, gusts 5 mph8 km/h	41%	3%	4
Sun 3p	Sunny	64°18° (likely 62°17° to 66°19°)	64°18°	0%	0 mph0 km/h, gusts 6 mph10 km/h	40%	3%	3
Sun 4p	Sunny	65°18° (likely 62°17° to 66°19°)	65°18°	0%	0 mph0 km/h, gusts 5 mph9 km/h	38%	2%	2
Sun 5p	Sunny	63°17° (likely 61°16° to 65°18°)	63°17°	0%	0 mph0 km/h, gusts 5 mph8 km/h	41%	0%	1
Sun 6p	Clear	60°16° (likely 57°14° to 60°16°)	60°16°	0%	0 mph0 km/h, gusts 4 mph7 km/h	47%	0%	0
Sun 7p	Clear	55°13° (likely 53°12° to 56°13°)	55°13°	0%	0 mph0 km/h, gusts 4 mph7 km/h	59%	1%	0
Sun 8p	Clear	51°11° (likely 50°10° to 55°13°)	51°11°	0%	0 mph0 km/h, gusts 4 mph7 km/h	71%	0%	0
Sun 9p	Clear	49°9° (likely 45°7° to 56°13°)	49°9°	0%	0 mph0 km/h, gusts 2 mph4 km/h	80%	0%	0
Sun 10p	Clear	47°8° (likely 43°6° to 56°13°)	47°8°	0%	0 mph0 km/h, gusts 3 mph5 km/h	86%	0%	0
Sun 11p	Clear	46°8° (likely 40°4° to 54°12°)	46°8°	0%	0 mph0 km/h, gusts 4 mph7 km/h	89%	0%	0
Mon 12a	Clear	45°7° (likely 38°3° to 53°12°)	45°7°	0%	0 mph0 km/h, gusts 5 mph8 km/h	93%	0%	0
Mon 1a	Clear	44°7° (likely 37°3° to 52°11°)	44°7°	0%	0 mph0 km/h, gusts 6 mph9 km/h	96%	0%	0
Mon 2a	Clear	43°6° (likely 37°3° to 52°11°)	43°6°	0%	0 mph0 km/h, gusts 6 mph10 km/h	96%	0%	0

Days ahead

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

Today, Oct 24. Mostly sunny. High 63°17°, low 36°2°. Typical 64°18° / 46°8°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 39°4°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 63°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 50°10°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 36°2°
  Dry
Official NWS forecast
Today: Areas of frost before 10am. Sunny, with a high near 63. Northeast wind 0 to 5 mph.
Tonight: Areas of frost. Partly cloudy, with a low around 36. North wind 0 to 5 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
60°16°–63°17°
Low, likely
36°2°–38°3°
Typical high / low
64°18° / 46°8°
Wind
6 mph10 km/h
UV peak
4
Tomorrow, Oct 25. Sunny. High 65°18°, low 40°4°. Typical 64°18° / 46°8°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 37°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 65°18°
  Dry
3. Evening
  6 PM–midnight
  Clear, 51°11°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 42°6°
  Dry
Official NWS forecast
Day: Patchy frost before 9am. Sunny, with a high near 65. Northwest wind 0 to 5 mph.
Night: Clear, with a low around 40. Northwest wind 0 to 5 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–66°19°
Low, likely
34°1°–40°4°
Typical high / low
64°18° / 46°8°
Wind
6 mph10 km/h
UV peak
4
Monday, Oct 26. Mostly sunny. High 68°20°, low 48°9°. Typical 63°17° / 45°7°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 42°6°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 68°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 57°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 51°11°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 68.
Night: Clear, with a low around 48.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
67°19°–69°21°
Low, likely
36°2°–48°9°
Typical high / low
63°17° / 45°7°
Wind
8 mph13 km/h, gusts 17 mph27 km/h
UV peak
4
Tuesday, Oct 27. Partly sunny. High 65°18°, low 44°7°. Typical 63°17° / 45°7°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 50°10°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 63°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 52°11°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 42°6°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 65.
Night: Partly cloudy, with a low around 44.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
61°16°–66°19°
Low, likely
44°7°–50°10°
Typical high / low
63°17° / 45°7°
Wind
10 mph15 km/h, gusts 24 mph39 km/h
UV peak
4
Wednesday, Oct 28. Partly sunny. High 62°17°, low 47°8°. Typical 63°17° / 45°7°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 41°5°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 61°16°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 53°12°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 45°7°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 62.
Night: Mostly cloudy, with a low around 47.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
60°16°–64°18°
Low, likely
38°3°–47°8°
Typical high / low
63°17° / 45°7°
Wind
8 mph13 km/h, gusts 15 mph24 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 68°20°, low 50°10°. Typical 62°17° / 44°7°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 45°7°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 65°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 56°13°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 49°9°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 68.
Night: Partly cloudy, with a low around 50.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–68°20°
Low, likely
41°5°–50°10°
Typical high / low
62°17° / 44°7°
Wind
8 mph13 km/h, gusts 29 mph47 km/h
UV peak
4
Friday, Oct 30. Sunny. High 69°21°, low 47°8°. Typical 62°17° / 44°7°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 70°21°
  Dry
3. Evening
  6 PM–midnight
  Clear, 58°14°
  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 69.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
66°19°–73°23°
Low, likely
43°6°–50°10°
Typical high / low
62°17° / 44°7°
Wind
10 mph15 km/h, gusts 24 mph38 km/h
UV peak
4
Saturday, Oct 31. Cloudy. High 69°21°, low 47°8°. Typical 62°17° / 44°7°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 46°8°
  Dry
2. Afternoon
  noon–6 PM
  Partly sunny, 68°20°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 58°14°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 49°10°
  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
63°17°–74°23°
Low, likely
42°6°–52°11°
Typical high / low
62°17° / 44°7°
Wind
9 mph15 km/h, gusts 24 mph38 km/h
UV peak
3
Sunday, Nov 1. Cloudy. High 66°19°, low 50°10°. Typical 61°16° / 43°6°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 49°9°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 65°18°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 58°15°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 56°13°
  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
60°16°–71°22°
Low, likely
46°8°–54°12°
Typical high / low
61°16° / 43°6°
Wind
8 mph13 km/h, gusts 18 mph28 km/h
UV peak
2
Monday, Nov 2. Cloudy. High 69°21°, low 57°14°. Typical 61°16° / 43°6°. Rain 0.18 in4.6 mm, 20% chance. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 59°15°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 70°21°
  20% chance · 0.07 in1.9 mm
3. Evening
  6 PM–midnight
  Mostly clear, 62°16°
  20% chance · 0.06 in1.5 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
67°19°–70°21°
Low, likely
56°13°–59°15°
Typical high / low
61°16° / 43°6°
Wind
15 mph24 km/h, gusts 41 mph66 km/h
UV peak
3

10 days15 days30 days

The outlook

Today
Dry, high 63°, low 36°.
Tomorrow
Dry, high 65°, low 40°.
Monday
Dry, high 68°, low 48°, warming up.
Rest of week
Mostly dry, highs 62–69°.

Want the meteorologists’ reasoning? Read the NWS forecast discussion (PHI) (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

Schuylkill River at Philadelphia

4.1 mi

Below flood stage

Level: 6.1 ft
Flow: 1,060 cfs

Forecast peak 6.0 ft Sat 8 AM

Reading from Sat 1 AM · NWS gauge page

Schuylkill River near Philadelphia near 30th Street

4.9 mi

Below flood stage

Level: 3.6 ft

Forecast peak 4.8 ft Sat 1 PM

Reading from Sat 1:45 AM · NWS gauge page

Delaware River at USCG Station Washington Street (IN MLLW)

7.5 mi

Below flood stage

Level: 7.0 ft

Forecast peak 8.0 ft Sat 1 PM

Reading from Sat 2 AM · NWS gauge page

Schuylkill River at Norristown

9.0 mi

Below flood stage

Level: 8.1 ft
Flow: 1,330 cfs

Forecast peak 8.1 ft Sat 8 AM

Reading from Sat 1:30 AM · NWS gauge page

For your home

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

Heating this week

About 59% less heating than a typical week.

This week 31Typical 77

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 15 hours are near freezing and damp, when outdoor units defrost more often.

Comfort

Dry air outside (dew point 37°F).

Open the windows?

Today, 1:00 PM–6:00 PM

Good stretch to open the windows.

Is this typical?

Philadelphia International Airport · official normals 1991–2020 · records 1873–2026

Oct 24, today vs a typical year

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

Last 7 days vs normal

On average 1°0° colder than normal (daily mean temperature).

−6°−3°SunOct 18
−2°−1°MonOct 19
+3°+1°TueOct 20
+2°+1°WedOct 21
+2°+1°ThuOct 22
—FriOct 23
—SatOct 24

Merion Station weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 47 min; Losing 2 min 25 s a day; shortest Dec 21, 1 h 28 min less
Golden hour: 5:31–6:25 PM; Morning 7:04–7:58 AM
Blue hour: 6:25–6:36 PM; Morning 6:53–7:04 AM; first light 6:53 AM

Stars tonight? Good

Clear 3:26–6:53 AM; moon 96% lit, sets 5:32 AM.

Moon

Waxing gibbous

96% lit · growing

Today: sets 5:32 AM · rises 5:05 PM
Full moon: Oct 26
New moon: Nov 9

Looking southwest from Merion Station. The highest point on the skyline is about 3,400 ft, 55 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

Merion Station, PA weather

Next 2 hours

Next 48 hours

Days ahead

The outlook

Today

Tomorrow

Monday

Rest of week

What changed since yesterday

Radar

Rivers

Schuylkill River at Philadelphia

Schuylkill River near Philadelphia near 30th Street

Delaware River at USCG Station Washington Street (IN MLLW)

Schuylkill River at Norristown

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