# Herndon Weather

**Location**  
Herndon, 20170, Virginia, United States  
·  
As of 9:22 pm GMT-4

[Now79°78°77°\  
\  
Mostly Cloudy Night\  
\  
Mostly Cloudy\  
\  
Feels Like\  
\  
77°\  
\  
HHigh\  
\  
83°\  
\  
LLow\  
\  
68°\  
\  
Chance of Rain\  
\  
7%\  
\  
0 in](/content/en-BS/us/virginia/herndon/postcode/20170/hourbyhour/index.html)

## Today's outlook

Tonight's low temperature will be a little cooler than last night's.

#### Hourly Forecast

| Time  | Condition              | Temp  |
|-------|------------------------|-------|
| 00:00 | Cloudy                 | 77°   |
| 01:00 | Mostly Cloudy Night    | 77°   |
| 02:00 | Mostly Cloudy Night    | 76°   |
| 03:00 | Mostly Cloudy Night    | 76°   |
| 04:00 | Mostly Cloudy Night    | 77°   |
| 05:00 | Mostly Cloudy Night    | 76°   |
| 06:00 | Mostly Cloudy Night    | 75°   |
| 07:00 | Cloudy                 | 74°   |
| 08:00 | Partly Cloudy Day      | 76°   |
| 09:00 | Mostly Cloudy Day      | 77°   |
| 10:00 | Mostly Cloudy Day      | 77°   |
| 11:00 | Cloudy                 | 79°   |
| 12:00 | Cloudy                 | 78°   |
| 13:00 | Cloudy                 | 77°   |
| 14:00 | Mostly Cloudy Day      | 76°   |
| 15:00 | Mostly Cloudy Day      | 78°   |
| 16:00 | Partly Cloudy Day      | 82°   |
| 17:00 | Mostly Cloudy Day      | 82°   |
| 18:00 | Mostly Cloudy Day      | 82°   |
| 19:00 | Mostly Cloudy Day      | 80°   |
| 20:00 | Cloudy                 | 78°   |
| 21:00 | Cloudy                 | 77°   |

#### Wind

- **Wind:** 4 mph N  
- **Humidity:** 81%  
- **Air Quality:** 63 - Moderate  
- **Dew Point:** 71°  
- **Pressure:** 30.05 in  
- **UV Index:** 0 of 11  
- **Visibility:** 10 mi  
  
### Daily Forecast

| Date    | Condition              | Rain Chance | Low  | High |
|---------|------------------------|-------------|------|------|
| Tonight | Partly Cloudy Night    | 8%          | 68°  | 83°  |
| Sat 15  | Mostly Clear Day       | 7%          | 73°  | 87°  |
| Sun 16  | Thunderstorms          | 81%         | 73°  | 78°  |
| Mon 17  | Partly Cloudy Day      | 23%         | 68°  | 89°  |
| Tue 18  | Mostly Clear Day       | 5%          | 65°  | 85°  |
| Wed 19  | Mostly Clear Day       | 7%          | 71°  | 88°  |
| Thu 20  | Scattered Thunderstorms | 52%         | 66°  | 87°  |

## Air Quality Index

63  
**Moderate**  
Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.  
[See details](/content/en-BS/forecast/air-quality/l/38.97,-77.386)

## Health & Activities

- **Grass Pollen:** Seasonal Allergies and Pollen Count Forecast - Grass pollen is moderate in your area  
- **Flu Risk:** Very low in your area