As of 18:32 EDT

Weather in Herndon, PA

67°

Herndon, Monday, 12 October, 18:32

Partly cloudy. Feels like 67°. High 70°, low 56°.

Pressure29.88 inHg

Wind0 mph N

Humidity82%

Visibility6.2 mi

Dew point61°

See detailed hourly forecast

Tue, 1379° / 56°

79 °

Herndon, Tuesday, 13 October

Mostly clear. High 79°, low 56°.

Pressure29.91 inHg

Wind8.4 mph S

Humidity71%

Visibility6.2 mi

Dew point63°

Wed, 1475° / 61°

75 °

Herndon, Wednesday, 14 October

Light rain. High 75°, low 61°.

Pressure29.94 inHg

Wind4.8 mph W

Humidity81%

Visibility6.2 mi

Dew point65°

Thu, 1562° / 53°

62 °

Herndon, Thursday, 15 October

Partly cloudy. High 62°, low 53°.

Pressure30.24 inHg

Wind4.9 mph NE

Humidity62%

Visibility6.2 mi

Dew point47°

Fri, 1671° / 52°

0.39

71 °

Herndon, Friday, 16 October

Rain. High 71°, low 52°.

Pressure29.56 inHg

Wind8.7 mph SW

Humidity88%

Visibility5.9 mi

Dew point65°

Sat, 1750° / 41°

50 °

Herndon, Saturday, 17 October

Clear. High 50°, low 41°.

Pressure30.27 inHg

Wind19.1 mph NW

Humidity54%

Visibility—

Dew point30°

Sun, 1855° / 37°

55 °

Herndon, Sunday, 18 October

Clear. High 55°, low 37°.

Pressure30.53 inHg

Wind7.9 mph SW

Humidity53%

Visibility—

Dew point32°

Mon, 1959° / 34°

59 °

Herndon, Monday, 19 October

Clear. High 59°, low 34°.

Pressure30.62 inHg

Wind11.1 mph S

Humidity53%

Visibility—

Dew point32°

Tue, 2063° / 43°

63 °

Herndon, Tuesday, 20 October

Overcast. High 63°, low 43°.

Pressure30.45 inHg

Wind2.6 mph SW

Humidity71%

Visibility—

Dew point45°

Wed, 2166° / 45°

66 °

Herndon, Wednesday, 21 October

Clear. High 66°, low 45°.

Pressure30.30 inHg

Wind4 mph N

Humidity64%

Visibility—

Dew point45°

Thu, 2266° / 46°

66 °

Herndon, Thursday, 22 October

Partly cloudy. High 66°, low 46°.

Pressure30.30 inHg

Wind4.1 mph N

Humidity65%

Visibility—

Dew point46°

Fri, 2368° / 49°

68 °

Herndon, Friday, 23 October

Overcast. High 68°, low 49°.

Pressure30.27 inHg

Wind7.9 mph SW

Humidity66%

Visibility—

Dew point47°

Sat, 2474° / 51°

74 °

Herndon, Saturday, 24 October

Overcast. High 74°, low 51°.

Pressure30.00 inHg

Wind11.1 mph SW

Humidity62%

Visibility—

Dew point49°

Sun, 2563° / 48°

0.03

63 °

Herndon, Sunday, 25 October

Light rain. High 63°, low 48°.

Pressure29.80 inHg

Wind14.8 mph NW

Humidity60%

Visibility—

Dew point47°

Mon, 2660° / 46°

60 °

Herndon, Monday, 26 October

Clear. High 60°, low 46°.

Pressure30.21 inHg

Wind7.3 mph N

Humidity66%

Visibility—

Dew point44°

Tue, 2760° / 42°

60 °

Herndon, Tuesday, 27 October

Overcast. High 60°, low 42°.

Pressure30.27 inHg

Wind7 mph S

Humidity65%

Visibility—

Dew point42°

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.