EN
English Español

As of 18:03 EDT

Weather in Herndon, PA

84°Current weather

Herndon, Saturday, 8 August, 18:03

Partly cloudy. Feels like 93°. High 84°, low 70°.

Pressure29.94 inHg
Wind2 mph W
Humidity77%
Visibility6.2 mi
Dew point75°
Sun, 0986° / 70°0.06Light rain
86 °Light rain

Herndon, Sunday, 9 August

Light rain. High 86°, low 70°.

Pressure30.00 inHg
Wind6.6 mph NW
Humidity45%
Visibility6.2 mi
Dew point63°
Mon, 1089° / 68°0.11Rain
89 °Rain

Herndon, Monday, 10 August

Rain. High 89°, low 68°.

Pressure30.03 inHg
Wind5.3 mph SW
Humidity77%
Visibility6.2 mi
Dew point68°
Tue, 1189° / 68°0.6Heavy rain
89 °Heavy rain

Herndon, Tuesday, 11 August

Heavy rain. High 89°, low 68°.

Pressure29.94 inHg
Wind5.7 mph W
Humidity63%
Visibility6.2 mi
Dew point66°
Wed, 1283° / 66°0.06Light rain
83 °Light rain

Herndon, Wednesday, 12 August

Light rain. High 83°, low 66°.

Pressure29.80 inHg
Wind10 mph W
Humidity68%
Visibility6.2 mi
Dew point65°
Thu, 1381° / 63°0.04Light rain
81 °Light rain

Herndon, Thursday, 13 August

Light rain. High 81°, low 63°.

Pressure29.80 inHg
Wind13.4 mph NW
Humidity55%
Visibility—
Dew point62°
Fri, 1477° / 56°0Clear
77 °Clear

Herndon, Friday, 14 August

Clear. High 77°, low 56°.

Pressure29.97 inHg
Wind9.9 mph N
Humidity36%
Visibility—
Dew point45°
Sat, 1575° / 51°0Clear
75 °Clear

Herndon, Saturday, 15 August

Clear. High 75°, low 51°.

Pressure30.18 inHg
Wind12.3 mph NE
Humidity36%
Visibility—
Dew point44°
Sun, 1678° / 50°0Clear
78 °Clear

Herndon, Sunday, 16 August

Clear. High 78°, low 50°.

Pressure30.30 inHg
Wind4.8 mph N
Humidity33%
Visibility—
Dew point44°
Mon, 1785° / 56°0Overcast
85 °Overcast

Herndon, Monday, 17 August

Overcast. High 85°, low 56°.

Pressure30.12 inHg
Wind8.5 mph S
Humidity46%
Visibility—
Dew point57°
Tue, 1880° / 66°0.06Light rain
80 °Light rain

Herndon, Tuesday, 18 August

Light rain. High 80°, low 66°.

Pressure29.94 inHg
Wind7.5 mph S
Humidity65%
Visibility—
Dew point64°
Wed, 1978° / 61°0Partly cloudy
78 °Partly cloudy

Herndon, Wednesday, 19 August

Partly cloudy. High 78°, low 61°.

Pressure29.94 inHg
Wind12.3 mph N
Humidity56%
Visibility—
Dew point58°
Thu, 2067° / 56°0Overcast
67 °Overcast

Herndon, Thursday, 20 August

Overcast. High 67°, low 56°.

Pressure30.00 inHg
Wind3.5 mph NE
Humidity72%
Visibility—
Dew point55°
Fri, 2169° / 61°0.1Light rain
69 °Light rain

Herndon, Friday, 21 August

Light rain. High 69°, low 61°.

Pressure29.88 inHg
Wind2.6 mph NE
Humidity92%
Visibility—
Dew point64°
Sat, 2284° / 65°0Mostly clear
84 °Mostly clear

Herndon, Saturday, 22 August

Mostly clear. High 84°, low 65°.

Pressure29.77 inHg
Wind10.6 mph N
Humidity39%
Visibility—
Dew point54°
Sun, 2372° / 53°0Clear
72 °Clear

Herndon, Sunday, 23 August

Clear. High 72°, low 53°.

Pressure30.03 inHg
Wind13.6 mph N
Humidity35%
Visibility—
Dew point41°

About the monthly outlook

How accurate is a 30-day forecast?

The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for Herndon, PA are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.

What does "above normal" mean?

We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.

Where do the 66-year records come from?

They are real temperature extremes recorded in Herndon, PA since 1960: the highest and lowest reading for each calendar date, with the year it happened.

How often is it updated?

The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.