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As of 02:02 EDT

Weather in Herndon, PA

55°Current weather

Herndon, Saturday, 17 October, 02:02

Light rain. Feels like 54°. High 56°, low 39°.

Pressure29.94 inHg
Wind15 mph N
Humidity67%
Visibility6.2 mi
Dew point44°
Sun, 1858° / 35°0Clear
58 °Clear

Herndon, Sunday, 18 October

Clear. High 58°, low 35°.

Pressure30.59 inHg
Wind1.4 mph SW
Humidity54%
Visibility6.2 mi
Dew point37°
Mon, 1964° / 39°0Clear
64 °Clear

Herndon, Monday, 19 October

Clear. High 64°, low 39°.

Pressure30.47 inHg
Wind4 mph N
Humidity53%
Visibility6.2 mi
Dew point41°
Tue, 2064° / 48°0Clear
64 °Clear

Herndon, Tuesday, 20 October

Clear. High 64°, low 48°.

Pressure30.30 inHg
Wind10.5 mph N
Humidity58%
Visibility6.2 mi
Dew point45°
Wed, 2162° / 44°0Clear
62 °Clear

Herndon, Wednesday, 21 October

Clear. High 62°, low 44°.

Pressure30.33 inHg
Wind7.3 mph N
Humidity63%
Visibility—
Dew point40°
Thu, 2260° / 40°0Clear
60 °Clear

Herndon, Thursday, 22 October

Clear. High 60°, low 40°.

Pressure30.21 inHg
Wind7.4 mph N
Humidity65%
Visibility—
Dew point39°
Fri, 2364° / 40°0Mostly clear
64 °Mostly clear

Herndon, Friday, 23 October

Mostly clear. High 64°, low 40°.

Pressure30.27 inHg
Wind9.9 mph N
Humidity53%
Visibility—
Dew point37°
Sat, 2459° / 38°0Clear
59 °Clear

Herndon, Saturday, 24 October

Clear. High 59°, low 38°.

Pressure30.39 inHg
Wind5.3 mph NE
Humidity55%
Visibility—
Dew point35°
Sun, 2565° / 39°0Clear
65 °Clear

Herndon, Sunday, 25 October

Clear. High 65°, low 39°.

Pressure30.18 inHg
Wind11.8 mph NW
Humidity48%
Visibility—
Dew point33°
Mon, 2655° / 39°0Partly cloudy
55 °Partly cloudy

Herndon, Monday, 26 October

Partly cloudy. High 55°, low 39°.

Pressure30.36 inHg
Wind13.6 mph N
Humidity49%
Visibility—
Dew point28°
Tue, 2761° / 40°0Overcast
61 °Overcast

Herndon, Tuesday, 27 October

Overcast. High 61°, low 40°.

Pressure30.33 inHg
Wind3.6 mph W
Humidity43%
Visibility—
Dew point30°
Wed, 2862° / 50°0.17Light rain
62 °Light rain

Herndon, Wednesday, 28 October

Light rain. High 62°, low 50°.

Pressure30.03 inHg
Wind7.8 mph W
Humidity80%
Visibility—
Dew point49°
Thu, 2960° / 43°0Clear
60 °Clear

Herndon, Thursday, 29 October

Clear. High 60°, low 43°.

Pressure30.12 inHg
Wind7.4 mph N
Humidity74%
Visibility—
Dew point45°
Fri, 3053° / 43°0.01Light rain
53 °Light rain

Herndon, Friday, 30 October

Light rain. High 53°, low 43°.

Pressure30.00 inHg
Wind10.1 mph S
Humidity76%
Visibility—
Dew point44°
Sat, 3156° / 50°0.12Light rain
56 °Light rain

Herndon, Saturday, 31 October

Light rain. High 56°, low 50°.

Pressure29.62 inHg
Wind9.8 mph NW
Humidity96%
Visibility—
Dew point52°
Sun, 0151° / 48°0.17Light rain
51 °Light rain

Herndon, Sunday, 1 November

Light rain. High 51°, low 48°.

Pressure29.77 inHg
Wind17.6 mph N
Humidity89%
Visibility—
Dew point45°

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.