Frost Advisory
Starts in 5 h 29 min
When
From 1 AM to 9 AM EDT Sunday.
Where
Portions of central, northeast, and northern Maryland and northern Virginia.
Issued for this forecast zone · National Weather Service Baltimore MD/Washington DC
What, impacts and precautionsHide details
What
Temperatures as low as 33 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: Frederick; Carroll; Northern Baltimore; Cecil; Northwest Montgomery; Northwest Howard; Northwest Harford; Southeast Harford; Rappahannock; Culpeper; Northern Fauquier; Southern Fauquier; Western Loudoun; Eastern Loudoun; Northwest Prince William; Central and Southeast Prince William/Manassas/Manassas Park
See it on weather.gov (opens in a new tab)

Observed 7:10 PM EDT at KGAI

Green Valley, MD weather

Clear and 52°11°.

Forecasts agree

Now 52°11°

Clear

Wind: Calm; Light through 7 AM
Dew point: 43°6°; Comfortable
UV tomorrow: 4Moderate; Moderate 11 AM–5 PM · peak 4
Air quality: 30Good; Ozone · tomorrow moderate
Pressure: 30.54 inHg1034 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

Good hours for

Low 37°3° tomorrow at 7 AM
Above 50°10° tomorrow by 10 AM
High 62°17° tomorrow at 2 PM
Below 50°10° tomorrow night after 9 PM

TonightDown to 38°3° by 5 AM · Clear
Tomorrow morningUp to 54°12° by 11 AM · Clear
Tomorrow afternoonUp to 62°17° by 2 PM · Clear
Tomorrow nightDown to 40°4° by 3 AM · Clear
Monday morningUp to 55°13° by 11 AM · Clear
Monday afternoonUp to 67°19° by 3 PM · 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 7p	Clear	53°12° (likely 51°11° to 54°12°)	53°12°	0%	5 mph8 km/h from E, gusts 7 mph11 km/h	61%	14%	0
Sat 8p	Clear	48°9° (likely 48°9° to 51°11°)	47°8°	0%	3 mph5 km/h from SE, gusts 7 mph12 km/h	74%	7%	0
Sat 9p	Clear	47°8° (likely 47°8° to 50°10°)	46°8°	0%	3 mph5 km/h from E, gusts 7 mph11 km/h	74%	0%	0
Sat 10p	Clear	45°7° (likely 45°7° to 49°9°)	44°7°	0%	3 mph5 km/h from SE, gusts 6 mph10 km/h	79%	0%	0
Sat 11p	Clear	44°7° (likely 44°7° to 49°9°)	42°6°	0%	3 mph5 km/h from SE, gusts 6 mph9 km/h	82%	0%	0
Sun 12a	Clear	43°6° (likely 43°6° to 48°9°)	41°5°	0%	3 mph5 km/h from SE, gusts 8 mph12 km/h	86%	2%	0
Sun 1a	Clear	43°6° (likely 43°6° to 48°9°)	41°5°	0%	3 mph5 km/h from SE, gusts 7 mph11 km/h	89%	12%	0
Sun 2a	Clear	40°4° (likely 40°4° to 47°8°)	40°4°	0%	2 mph3 km/h from SE, gusts 7 mph12 km/h	92%	11%	0
Sun 3a	Clear	39°4° (likely 39°4° to 46°8°)	39°4°	0%	2 mph3 km/h from SE, gusts 4 mph6 km/h	96%	8%	0
Sun 4a	Clear	39°4° (likely 39°4° to 45°7°)	39°4°	0%	2 mph3 km/h from SE, gusts 4 mph7 km/h	92%	0%	0
Sun 5a	Clear	38°3° (likely 38°3° to 45°7°)	38°3°	0%	2 mph3 km/h from SE, gusts 5 mph8 km/h	96%	1%	0
Sun 6a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	2 mph3 km/h from SE, gusts 5 mph7 km/h	96%	2%	0
Sun 7a	Sunny	37°3° (likely 37°3° to 43°6°)	37°3°	0%	1 mph2 km/h from SE, gusts 5 mph8 km/h	96%	1%	0
Sun 8a	Sunny	38°3° (likely 38°3° to 44°7°)	38°3°	0%	2 mph3 km/h from SE, gusts 6 mph10 km/h	96%	0%	0
Sun 9a	Sunny	43°6° (likely 42°6° to 49°9°)	43°6°	0%	1 mph2 km/h from SE, gusts 4 mph7 km/h	89%	1%	1
Sun 10a	Sunny	50°10° (likely 50°10° to 54°12°)	50°10°	0%	0 mph0 km/h, gusts 5 mph7 km/h	77%	2%	2
Sun 11a	Sunny	54°12° (likely 54°12° to 58°14°)	54°12°	0%	1 mph2 km/h from S, gusts 6 mph9 km/h	69%	4%	3
Sun 12p	Sunny	57°14° (likely 57°14° to 60°16°)	57°14°	0%	1 mph2 km/h from S, gusts 7 mph12 km/h	62%	11%	4
Sun 1p	Sunny	60°16° (likely 60°16° to 62°17°)	60°16°	0%	1 mph2 km/h from S, gusts 6 mph9 km/h	55%	8%	4
Sun 2p	Sunny	62°17° (likely 62°17° to 63°17°)	62°17°	0%	1 mph2 km/h from S, gusts 7 mph11 km/h	52%	9%	4
Sun 3p	Sunny	62°17° (likely 62°17° to 64°18°)	62°17°	0%	1 mph2 km/h from S, gusts 7 mph12 km/h	52%	5%	4
Sun 4p	Sunny	62°17° (likely 62°17° to 64°18°)	62°17°	0%	2 mph3 km/h from S, gusts 7 mph11 km/h	54%	5%	3
Sun 5p	Sunny	62°17° (likely 61°16° to 62°17°)	62°17°	0%	2 mph3 km/h from S, gusts 7 mph11 km/h	54%	1%	1
Sun 6p	Clear	59°15° (likely 57°14° to 59°15°)	59°15°	0%	1 mph2 km/h from S, gusts 5 mph8 km/h	57%	2%	0
Sun 7p	Clear	55°13° (likely 54°12° to 55°13°)	55°13°	0%	1 mph2 km/h from S, gusts 4 mph6 km/h	66%	1%	0
Sun 8p	Clear	51°11° (likely 51°11° to 53°12°)	51°11°	0%	1 mph2 km/h from S, gusts 3 mph5 km/h	77%	1%	0
Sun 9p	Clear	47°8° (likely 47°8° to 51°11°)	47°8°	0%	1 mph2 km/h from S, gusts 4 mph6 km/h	86%	0%	0
Sun 10p	Clear	45°7° (likely 45°7° to 50°10°)	45°7°	0%	1 mph2 km/h from S, gusts 5 mph8 km/h	93%	0%	0
Sun 11p	Clear	44°7° (likely 44°7° to 49°9°)	44°7°	0%	1 mph2 km/h from S, gusts 6 mph9 km/h	93%	0%	0
Mon 12a	Clear	43°6° (likely 43°6° to 48°9°)	43°6°	0%	1 mph2 km/h from S, gusts 6 mph10 km/h	96%	1%	0
Mon 1a	Clear	42°6° (likely 42°6° to 48°9°)	42°6°	0%	1 mph2 km/h from S, gusts 7 mph11 km/h	100%	3%	0
Mon 2a	Clear	41°5° (likely 41°5° to 47°8°)	41°5°	0%	1 mph2 km/h from S, gusts 7 mph11 km/h	100%	7%	0
Mon 3a	Clear	40°4° (likely 40°4° to 47°8°)	40°4°	0%	1 mph2 km/h from S, gusts 6 mph10 km/h	96%	1%	0
Mon 4a	Clear	40°4° (likely 40°4° to 45°7°)	40°4°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	96%	0%	0
Mon 5a	Clear	40°4° (likely 40°4° to 45°7°)	40°4°	0%	2 mph3 km/h from W, gusts 6 mph9 km/h	96%	0%	0
Mon 6a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	1 mph2 km/h from W, gusts 5 mph8 km/h	100%	13%	0
Mon 7a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	1 mph2 km/h from W, gusts 5 mph8 km/h	100%	12%	0
Mon 8a	Sunny	38°3° (likely 38°3° to 44°7°)	38°3°	0%	1 mph2 km/h from W, gusts 6 mph9 km/h	100%	20%	0
Mon 9a	Sunny	43°6° (likely 43°6° to 48°9°)	43°6°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	93%	16%	1
Mon 10a	Sunny	49°9° (likely 49°9° to 53°12°)	48°9°	0%	3 mph5 km/h from W, gusts 8 mph14 km/h	80%	7%	2
Mon 11a	Sunny	55°13° (likely 55°13° to 58°14°)	55°13°	0%	3 mph5 km/h from W, gusts 9 mph15 km/h	69%	0%	3
Mon 12p	Sunny	59°15° (likely 59°15° to 62°17°)	59°15°	0%	5 mph8 km/h from W, gusts 10 mph16 km/h	62%	0%	4
Mon 1p	Sunny	63°17° (likely 63°17° to 64°18°)	63°17°	0%	5 mph8 km/h from NW, gusts 9 mph15 km/h	56%	0%	4
Mon 2p	Sunny	65°18° (likely 65°18° to 66°19°)	65°18°	0%	6 mph10 km/h from NW, gusts 10 mph16 km/h	52%	0%	4
Mon 3p	Sunny	67°19° (likely 65°18° to 67°19°)	67°19°	0%	6 mph10 km/h from NW, gusts 11 mph18 km/h	49%	0%	4
Mon 4p	Sunny	67°19° (likely 64°18° to 67°19°)	67°19°	0%	5 mph8 km/h from NW, gusts 12 mph19 km/h	52%	0%	3
Mon 5p	Sunny	67°19° (likely 63°17° to 67°19°)	67°19°	0%	3 mph5 km/h from NW, gusts 11 mph17 km/h	52%	0%	1
Mon 6p	Clear	64°18° (likely 58°14° to 64°18°)	64°18°	0%	2 mph3 km/h from NW, gusts 6 mph9 km/h	58%	0%	0

Days ahead

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

Today, Oct 24. Sunny. High 61°16°, low 35°2°. Typical 62°17° / 44°7°. Dry. Forecasts agree.
1. Evening
  6 PM–midnight
  Clear, 48°9°
  Dry
2. Overnight
  midnight–6 AM
  Clear, 38°3°
  Dry
Official NWS forecast
Tonight: Clear, with a low around 35. Southeast wind around 5 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
60°16°–62°17°
Low, likely
35°2°–38°3°
Typical high / low
62°17° / 44°7°
Wind
8 mph13 km/h, gusts 14 mph22 km/h
UV peak
4
Tomorrow, Oct 25. Sunny. High 63°17°, low 37°3°. Typical 61°16° / 43°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 38°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Clear, 51°11°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 40°4°
  Dry
Official NWS forecast
Day: Patchy frost between 7am and 8am. Sunny, with a high near 63. South wind around 2 mph.
Night: Clear, with a low around 37. South wind around 2 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
63°17°–64°18°
Low, likely
37°3°–43°6°
Typical high / low
61°16° / 43°6°
Wind
7 mph12 km/h
UV peak
4
Monday, Oct 26. Mostly sunny. High 68°20°, low 47°8°. Typical 61°16° / 43°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 38°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 67°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 55°13°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 48°9°
  Dry
Official NWS forecast
Day: Sunny, with a high near 68. West wind 1 to 6 mph.
Night: Mostly clear, with a low around 47. Northwest wind 1 to 5 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
65°18°–68°20°
Low, likely
39°4°–47°8°
Typical high / low
61°16° / 43°6°
Wind
7 mph12 km/h, gusts 15 mph24 km/h
UV peak
4
Tuesday, Oct 27. Mostly sunny. High 66°19°, low 43°6°. Typical 60°16° / 42°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 64°18°
  Dry
3. Evening
  6 PM–midnight
  Clear, 53°12°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 45°7°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 66.
Night: Mostly clear, with a low around 43.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
63°17°–66°19°
Low, likely
43°6°–49°9°
Typical high / low
60°16° / 42°6°
Wind
11 mph17 km/h, gusts 21 mph33 km/h
UV peak
4
Wednesday, Oct 28. Cloudy. High 64°18°, low 47°8°. Typical 60°16° / 42°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Partly sunny, 45°7°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 62°17°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 53°12°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 48°9°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Partly sunny, with a high near 64.
Night: Mostly cloudy, with a low around 47.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
61°16°–64°18°
Low, likely
41°5°–48°9°
Typical high / low
60°16° / 42°6°
Wind
8 mph12 km/h, gusts 18 mph29 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 69°21°, low 48°9°. Typical 60°16° / 42°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 67°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 57°14°
  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 69.
Night: Mostly clear, with a low around 48.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
66°19°–69°21°
Low, likely
46°8°–48°9°
Typical high / low
60°16° / 42°6°
Wind
7 mph12 km/h, gusts 24 mph38 km/h
UV peak
4
Friday, Oct 30. Mostly sunny. High 73°23°, low 49°9°. Typical 60°16° / 41°5°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 49°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 73°23°
  Dry
3. Evening
  6 PM–midnight
  Clear, 61°16°
  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 73.
Night: Mostly clear, with a low around 49.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
73°23°
Low, likely
45°7°–51°11°
Typical high / low
60°16° / 41°5°
Wind
9 mph14 km/h, gusts 29 mph47 km/h
UV peak
4
Saturday, Oct 31. Partly sunny. High 70°21°, low 49°9°. Typical 59°15° / 41°5°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Partly sunny, 49°10°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 70°21°
  Dry
3. Evening
  6 PM–midnight
  Partly cloudy, 58°14°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 54°12°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 70.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
63°17°–71°22°
Low, likely
46°8°–53°12°
Typical high / low
59°15° / 41°5°
Wind
11 mph17 km/h, gusts 29 mph47 km/h
UV peak
3
Sunday, Nov 1. Drizzle. High 69°21°, low 52°11°. Typical 59°15° / 41°5°. Rain 0.02 in0.5 mm, 30% chance. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 54°12°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 68°20°
  30% chance
3. Evening
  6 PM–midnight
  Drizzle, 64°18°
  30% chance · 0.05 in1.3 mm
4. Overnight
  midnight–6 AM
  Drizzle, 60°16°
  30% chance · 0.15 in3.8 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
66°19°–70°21°
Low, likely
50°10°–56°13°
Typical high / low
59°15° / 41°5°
Wind
12 mph19 km/h, gusts 21 mph33 km/h
UV peak
3
Monday, Nov 2. Showers. High 71°22°, low 58°14°. Typical 58°14° / 40°4°. Rain 0.61 in15 mm, 30% chance. Mostly agree.
1. Morning
  6 AM–noon
  Drizzle, 61°16°
  30% chance · 0.08 in2.1 mm
2. Afternoon
  noon–6 PM
  Drizzle, 72°22°
  Dry
3. Evening
  6 PM–midnight
  Clear, 62°17°
  20% chance · 0.43 in11 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
70°21°–76°24°
Low, likely
55°13°–65°18°
Typical high / low
58°14° / 40°4°
Wind
18 mph28 km/h, gusts 37 mph60 km/h
UV peak
3

10 days15 days30 days

The outlook

Today
Dry, high 61°, low 35°.
Tomorrow
Dry, high 63°, low 37°.
Monday
Dry, high 68°, low 47°, warming up.
Rest of week
Mostly dry, highs 64–73°.

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

Monocacy River near Frederick at Interstate 70

7.9 mi

Below flood stage

Level: 1.7 ft
Flow: 173 cfs

Forecast peak 1.7 ft Sat 8 PM

Reading from Sat 5:30 PM · NWS gauge page

Soper Branch at Hyattstown, MD

5.7 mi

Below flood stage

Level: 0.4 ft
Flow: under 1 cfs

Reading from Sat 4:55 PM · NWS gauge page

LITTLE SENECA CREEK TRIBUTARY NEAR CLARKSBURG, MD

7.7 mi

Below flood stage

Level: 4.3 ft
Flow: under 1 cfs

Reading from Sat 5 PM · NWS gauge page

Little Seneca Creek Tributary at Brink, MD

8.2 mi

Below flood stage

Level: 4.7 ft
Flow: 1 cfs

Reading from Sat 4:55 PM · 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 31Typical 95

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

Comfort

Dry air outside (dew point 43°F).

Open the windows?

Sun, 1:00 PM–5:00 PM

Good stretch to open the windows.

Is this typical?

Damascus 3 Ssw · official normals 1991–2020 · records 1993–2026

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).

−8°−4°SunOct 18
−3°−2°MonOct 19
+1°TueOct 20
−1°WedOct 21
+1°ThuOct 22
±0°FriOct 23
—SatOct 24

Green Valley weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 49 min; Losing 2 min 25 s a day; shortest Dec 21, 1 h 25 min less
Golden hour: 5:40–6:34 PM; Morning 7:11–8:05 AM
Blue hour: 6:34–6:44 PM; Morning 7:00–7:11 AM; first light 7:00 AM

Stars tonight? Fair

Clear 7:31 PM–7:01 AM, but the moon is 99% lit and up.

Moon

Waxing gibbous

98% lit · growing

Today: sets 5:40 AM · rises 5:13 PM
Full moon: Oct 26
New moon: Nov 9

Looking northwest from Green Valley. The highest point on the skyline is about 2,500 ft, 27 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

Green Valley, MD weather

Next 2 hours

Next 48 hours

Days ahead

The outlook

Today

Tomorrow

Monday

Rest of week

What changed since yesterday

Radar

Rivers

Monocacy River near Frederick at Interstate 70

Soper Branch at Hyattstown, MD

LITTLE SENECA CREEK TRIBUTARY NEAR CLARKSBURG, MD

Little Seneca Creek Tributary at Brink, MD

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? Fair

Moon