Observed 1:35 PM EDT at KIAD

Difficult Run, VA weather

Partly cloudy and 63°17°, jacket by 7 PM.

Mostly agree

Now 63°17°

Partly sunny

Wind: 5 mph8 km/h; From the east. Up to 6 mph10 km/h through 1 AM
Dew point: 41°5°; Comfortable
UV index: 4Moderate; Moderate until 3 PM
Air quality: 37Good; PM2.5 (fine particles) · tomorrow moderate
Pressure: 30.53 inHg1034 hPa; Falling · −0.05 inHg−1.7 hPa in 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

About the same as this time yesterday (59°15° then, 60°16° now)

Good hours for

High 63°17° today at 3 PM
Below 50°10° tonight after 9 PM
Low 37°3° tomorrow at 6 AM
Above 50°10° tomorrow by 10 AM

This afternoonNear 61°16° · Clear
TonightDown to 38°3° by 4 AM · Clear
Tomorrow morningUp to 56°13° by 11 AM · Clear
Tomorrow afternoonUp to 66°19° by 3 PM · Clear
Tomorrow nightDown to 41°5° by 5 AM · Clear
Monday morningUp to 58°14° by 11 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 1p	Sunny	60°16° (likely 59°15° to 61°16°)	60°16°	0%	5 mph8 km/h from E, gusts 9 mph14 km/h	47%	14%	4
Sat 2p	Sunny	62°17° (likely 59°15° to 63°17°)	62°17°	0%	6 mph10 km/h from SE, gusts 9 mph14 km/h	44%	14%	3
Sat 3p	Sunny	63°17° (likely 60°16° to 63°17°)	63°17°	0%	5 mph8 km/h from SE, gusts 7 mph12 km/h	43%	14%	2
Sat 4p	Partly sunny	63°17° (likely 60°16° to 63°17°)	63°17°	0%	5 mph8 km/h from E, gusts 7 mph11 km/h	43%	23%	1
Sat 5p	Partly sunny	62°17° (likely 59°15° to 62°17°)	62°17°	0%	5 mph8 km/h from E, gusts 8 mph13 km/h	44%	23%	1
Sat 6p	Mostly clear	58°14° (likely 56°13° to 59°15°)	58°14°	0%	3 mph5 km/h from E, gusts 8 mph13 km/h	53%	22%	0
Sat 7p	Clear	53°12° (likely 52°11° to 55°13°)	53°12°	0%	3 mph5 km/h from E, gusts 8 mph13 km/h	64%	18%	0
Sat 8p	Clear	51°11° (likely 50°10° to 52°11°)	51°11°	0%	3 mph5 km/h from E, gusts 7 mph11 km/h	71%	12%	0
Sat 9p	Clear	48°9° (likely 48°9° to 50°10°)	48°9°	0%	2 mph3 km/h from E, gusts 6 mph10 km/h	80%	4%	0
Sat 10p	Clear	46°8° (likely 46°8° to 49°9°)	46°8°	0%	2 mph3 km/h from E, gusts 6 mph10 km/h	86%	15%	0
Sat 11p	Clear	43°6° (likely 43°6° to 48°9°)	43°6°	0%	1 mph2 km/h from E, gusts 6 mph9 km/h	93%	27%	0
Sun 12a	Partly cloudy	42°6° (likely 42°6° to 48°9°)	42°6°	0%	1 mph2 km/h from E, gusts 4 mph7 km/h	96%	42%	0
Sun 1a	Clear	42°6° (likely 42°6° to 47°8°)	42°6°	0%	1 mph2 km/h from E, gusts 5 mph8 km/h	96%	22%	0
Sun 2a	Clear	41°5° (likely 41°5° to 47°8°)	41°5°	0%	1 mph2 km/h from NE, gusts 6 mph9 km/h	100%	15%	0
Sun 3a	Clear	39°4° (likely 39°4° to 45°7°)	39°4°	0%	1 mph2 km/h from NE, gusts 5 mph8 km/h	100%	13%	0
Sun 4a	Clear	38°3° (likely 38°3° to 45°7°)	38°3°	0%	1 mph2 km/h from N, gusts 3 mph5 km/h	100%	10%	0
Sun 5a	Clear	38°3° (likely 38°3° to 44°7°)	38°3°	0%	1 mph2 km/h from N, gusts 3 mph4 km/h	100%	7%	0
Sun 6a	Clear	37°3° (likely 37°3° to 43°6°)	37°3°	0%	1 mph2 km/h from N, gusts 3 mph5 km/h	100%	1%	0
Sun 7a	Sunny	37°3° (likely 37°3° to 42°6°)	37°3°	0%	1 mph2 km/h from N, gusts 4 mph6 km/h	100%	6%	0
Sun 8a	Mostly sunny	37°3° (likely 37°3° to 42°6°)	37°3°	0%	2 mph3 km/h from N, gusts 3 mph5 km/h	100%	13%	0
Sun 9a	Sunny	43°6° (likely 43°6° to 47°8°)	43°6°	0%	1 mph2 km/h from N, gusts 4 mph6 km/h	96%	27%	1
Sun 10a	Sunny	50°10° (likely 50°10° to 53°12°)	50°10°	0%	1 mph2 km/h from N, gusts 7 mph11 km/h	77%	6%	2
Sun 11a	Sunny	56°13° (likely 56°13° to 58°14°)	56°13°	0%	1 mph2 km/h from N, gusts 6 mph9 km/h	64%	6%	3
Sun 12p	Mostly sunny	60°16° (likely 60°16° to 61°16°)	60°16°	0%	1 mph2 km/h from NE, gusts 6 mph10 km/h	55%	9%	4
Sun 1p	Mostly sunny	62°17° (likely 62°17° to 63°17°)	62°17°	0%	1 mph2 km/h from E, gusts 4 mph7 km/h	52%	15%	4
Sun 2p	Mostly sunny	65°18° (likely 63°17° to 65°18°)	65°18°	0%	1 mph2 km/h from SE, gusts 6 mph9 km/h	45%	12%	4
Sun 3p	Sunny	66°19° (likely 64°18° to 66°19°)	66°19°	0%	1 mph2 km/h from SE, gusts 6 mph9 km/h	43%	9%	4
Sun 4p	Sunny	66°19° (likely 63°17° to 66°19°)	66°19°	0%	1 mph2 km/h from SE, gusts 6 mph10 km/h	43%	14%	3
Sun 5p	Sunny	65°18° (likely 62°17° to 65°18°)	65°18°	0%	1 mph2 km/h from SE, gusts 6 mph10 km/h	45%	21%	1
Sun 6p	Clear	62°17° (likely 58°14° to 62°17°)	62°17°	0%	0 mph0 km/h, gusts 5 mph8 km/h	52%	2%	0
Sun 7p	Clear	56°13° (likely 55°13° to 56°13°)	56°13°	0%	1 mph2 km/h from SE, gusts 5 mph8 km/h	66%	1%	0
Sun 8p	Clear	53°12° (likely 52°11° to 55°13°)	53°12°	0%	1 mph2 km/h from SE, gusts 4 mph6 km/h	77%	0%	0
Sun 9p	Clear	51°11° (likely 50°10° to 53°12°)	51°11°	0%	1 mph2 km/h from SE, gusts 5 mph8 km/h	83%	0%	0
Sun 10p	Clear	48°9° (likely 48°9° to 50°10°)	48°9°	0%	1 mph2 km/h from S, gusts 5 mph9 km/h	89%	0%	0
Sun 11p	Clear	46°8° (likely 46°8° to 48°9°)	46°8°	0%	0 mph0 km/h, gusts 5 mph9 km/h	96%	1%	0
Mon 12a	Clear	45°7° (likely 45°7° to 47°8°)	45°7°	0%	0 mph0 km/h, gusts 5 mph9 km/h	96%	1%	0
Mon 1a	Clear	44°7° (likely 44°7° to 46°8°)	44°7°	0%	1 mph2 km/h from SW, gusts 4 mph7 km/h	100%	1%	0
Mon 2a	Clear	43°6° (likely 43°6° to 45°7°)	43°6°	0%	1 mph2 km/h from W, gusts 5 mph8 km/h	100%	5%	0
Mon 3a	Clear	42°6° (likely 42°6° to 44°7°)	42°6°	0%	1 mph2 km/h from W, gusts 6 mph9 km/h	100%	12%	0
Mon 4a	Clear	42°6° (likely 41°5° to 44°7°)	42°6°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	100%	13%	0
Mon 5a	Clear	41°5° (likely 41°5° to 44°7°)	41°5°	0%	2 mph3 km/h from W, gusts 7 mph11 km/h	100%	14%	0
Mon 6a	Clear	39°4° (likely 39°4° to 44°7°)	39°4°	0%	2 mph3 km/h from W, gusts 6 mph10 km/h	100%	15%	0
Mon 7a	Sunny	38°3° (likely 38°3° to 44°7°)	38°3°	0%	2 mph3 km/h from W, gusts 6 mph10 km/h	100%	22%	0
Mon 8a	Sunny	39°4° (likely 36°2° to 45°7°)	39°4°	0%	2 mph3 km/h from W, gusts 6 mph9 km/h	100%	22%	0
Mon 9a	Sunny	44°7° (likely 38°3° to 51°11°)	44°7°	0%	2 mph3 km/h from W, gusts 5 mph8 km/h	89%	27%	1
Mon 10a	Sunny	51°11° (likely 46°8° to 55°13°)	51°11°	0%	3 mph5 km/h from NW, gusts 7 mph11 km/h	77%	19%	2
Mon 11a	Sunny	58°14° (likely 54°12° to 59°15°)	58°14°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	64%	0%	3
Mon 12p	Sunny	63°17° (likely 59°15° to 63°17°)	63°17°	0%	3 mph5 km/h from NW, gusts 8 mph13 km/h	54%	1%	4

Days ahead

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

Today, Oct 24. Mostly sunny. High 63°17°, low 37°3°. Typical 65°18° / 42°6°. Dry. Mostly agree.
1. Afternoon
  noon–6 PM
  Sunny, 63°17°
  Dry
2. Evening
  6 PM–midnight
  Clear, 51°11°
  Dry
3. Overnight
  midnight–6 AM
  Clear, 38°3°
  Dry
Official NWS forecast
Today: Sunny, with a high near 63. Southeast wind around 6 mph.
Tonight: Patchy fog after midnight. Mostly clear, with a low around 37. East wind around 3 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
60°16°–63°17°
Low, likely
36°2°–39°4°
Typical high / low
65°18° / 42°6°
Wind
6 mph9 km/h, gusts 13 mph22 km/h
UV peak
4
Tomorrow, Oct 25. Sunny. High 66°19°, low 38°3°. Typical 64°18° / 42°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 37°3°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 53°12°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 41°5°
  Dry
Official NWS forecast
Day: Patchy frost and patchy fog before 10am. Sunny, with a high near 66. Northeast wind around 2 mph.
Night: Clear, with a low around 38. South wind around 2 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
63°17°–66°19°
Low, likely
38°3°–42°6°
Typical high / low
64°18° / 42°6°
Wind
6 mph9 km/h
UV peak
4
Monday, Oct 26. Sunny. High 69°21°, low 48°9°. Typical 64°18° / 41°5°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 39°4°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 67°20°
  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 69. Northwest wind around 5 mph.
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
64°18° / 41°5°
Wind
7 mph11 km/h, gusts 14 mph23 km/h
UV peak
4
Tuesday, Oct 27. Mostly sunny. High 67°19°, low 45°7°. Typical 64°18° / 41°5°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 66°19°
  Dry
3. Evening
  6 PM–midnight
  Clear, 56°13°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 47°8°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 67.
Night: Mostly clear, with a low around 45.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
65°18°–69°21°
Low, likely
44°7°–50°10°
Typical high / low
64°18° / 41°5°
Wind
8 mph13 km/h, gusts 19 mph30 km/h
UV peak
4
Wednesday, Oct 28. Cloudy. High 64°18°, low 47°8°. Typical 64°18° / 41°5°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 47°8°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 64°18°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 55°13°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 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
63°17°–66°19°
Low, likely
43°6°–48°9°
Typical high / low
64°18° / 41°5°
Wind
8 mph12 km/h, gusts 17 mph28 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 69°21°, low 49°9°. Typical 63°17° / 40°4°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Mostly sunny, 68°20°
  Dry
3. Evening
  6 PM–midnight
  Clear, 57°14°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 48°9°
  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 49.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
66°19°–69°21°
Low, likely
46°8°–49°9°
Typical high / low
63°17° / 40°4°
Wind
7 mph11 km/h, gusts 22 mph36 km/h
UV peak
4
Friday, Oct 30. Mostly sunny. High 72°22°, low 49°9°. Typical 63°17° / 40°4°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Sunny, 47°9°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 73°23°
  Dry
3. Evening
  6 PM–midnight
  Clear, 60°15°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 49°10°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Sunny, with a high near 72.
Night: Mostly clear, with a low around 49.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
72°22°–74°23°
Low, likely
44°7°–50°10°
Typical high / low
63°17° / 40°4°
Wind
7 mph10 km/h, gusts 26 mph41 km/h
UV peak
4
Saturday, Oct 31. Cloudy. High 71°22°, low 50°10°. Typical 62°17° / 40°4°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Mostly sunny, 49°9°
  Dry
2. Afternoon
  noon–6 PM
  Partly sunny, 73°23°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 61°16°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 54°12°
  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.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
69°21°–74°23°
Low, likely
43°6°–54°12°
Typical high / low
62°17° / 40°4°
Wind
6 mph10 km/h, gusts 27 mph44 km/h
UV peak
4
Sunday, Nov 1. Cloudy. High 69°21°, low 53°12°. Typical 62°17° / 40°4°. Rain 0.03 in0.8 mm, 20% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 54°12°
  Dry
2. Afternoon
  noon–6 PM
  Drizzle, 69°20°
  Dry
3. Evening
  6 PM–midnight
  Drizzle, 62°17°
  20% chance · 0.01 in0.3 mm
4. Overnight
  midnight–6 AM
  Drizzle, 59°15°
  20% chance · 0.06 in1.4 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
64°18°–72°22°
Low, likely
51°11°–55°13°
Typical high / low
62°17° / 40°4°
Wind
8 mph14 km/h, gusts 21 mph34 km/h
UV peak
2
Monday, Nov 2. Drizzle. High 70°21°, low 56°13°. Typical 62°17° / 39°4°. Rain 0.16 in4.1 mm, 30% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 61°16°
  Dry
2. Afternoon
  noon–6 PM
  Drizzle, 71°22°
  Dry
3. Evening
  6 PM–midnight
  Drizzle, 63°17°
  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
63°17°–75°24°
Low, likely
52°11°–59°15°
Typical high / low
62°17° / 39°4°
Wind
15 mph24 km/h

10 days15 days30 days

The outlook

Today
Dry, high 63°, low 37°.
Tomorrow
Dry, high 66°, low 38°, warming up.
Monday
Dry, high 69°, low 48°, warming up.
Rest of week
Mostly dry, highs 64–72°.

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

Horsepen Run above Oak Hill (West Ox Road Regional Pond)

3.2 mi

Level: 322 ft

Reading from Sat 6:45 AM · NWS gauge page

Unnamed Tributary near Fairfax Center

3.5 mi

Level: 383 ft

Reading from Sat 7:05 AM · NWS gauge page

Colvin Run at Lake Fairfax near Reston

4.3 mi

Level: 262 ft

Reading from Sat 11:15 AM · NWS gauge page

Difficult Run at Browns Mill Road / Wolf Trap

4.3 mi

Below flood stage

Level: 194 ft

Reading from Sat 8:05 AM · NWS gauge page

For your home

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

Heating this week

About 66% less heating than a typical week.

This week 30Typical 88

Heating degree days, base 65°F

Heat-pump hours, next 7 days

h below 47°F: 23
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 41°F).

Open the windows?

Today, 2:00 PM–5:00 PM

Good stretch to open the windows.

Is this typical?

Washington Dulles International Airport · official normals 1991–2020 · records 1960–2026

Oct 24, today vs a typical year

Today’s expected high is 2°1° colder than typical.

Last 7 days vs normal

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

−6°−3°SunOct 18
−3°−2°MonOct 19
+2°+1°TueOct 20
±0°WedOct 21
−2°−1°ThuOct 22
−1°FriOct 23
—SatOct 24

Difficult Run weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 50 min; Losing 2 min 21 s a day; shortest Dec 21, 1 h 24 min less
Golden hour: 5:41–6:35 PM; Morning 7:11–8:05 AM
Blue hour: 6:35–6:45 PM; Morning 7:00–7:11 AM; first light 7:00 AM

Stars tonight? Fair

Mostly clear 1–7:01 AM, but the moon is 99% lit and up.

Moon

Waxing gibbous

97% lit · growing

Today: sets 5:40 AM · rises 5:14 PM
Full moon: Oct 26
New moon: Nov 9

Looking west from Difficult Run. The highest point on the skyline is about 4,000 ft, 62 mi away.Skyline from USGS elevation data, heights drawn up to 6× taller. Sky, sun and moon as they are now.