# Daily Forecast

**Location**  
Herndon, 20170, Virginia, United States  
As of 9:26 p.m. EDT

## Day Conditions

| Day       | Conditions          | Temperature | Low | High | Wind      |
|-----------|---------------------|-------------|-----|------|-----------|
| Tonight   | Partly Cloudy Night | 69°         | 69° | 84°  | 5 mph NNW |
| Sat 15   | Partly Cloudy Day   | 73°         | 73° | 87°  | 5 mph ENE |
| Sun 16   | Thunderstorms       | 74°         | 74° | 81°  | 11 mph S  |
| Mon 17   | Partly Cloudy Day   | 68°         | 68° | 90°  | 11 mph NW |
| Tue 18   | Mostly Clear Day     | 65°         | 65° | 85°  | 7 mph NNW |
| Wed 19   | Mostly Clear Day     | 72°         | 72° | 88°  | 8 mph SW  |
| Thu 20   | Scattered Thunderstorms| 65°        | 65° | 87°  | 8 mph WNW |
| Fri 21   | Partly Cloudy Day   | 66°         | 66° | 81°  | 7 mph N   |
| Sat 22   | Showers             | 65°         | 65° | 77°  | 8 mph NE  |
| Sun 23   | Scattered Showers Day| 66°        | 66° | 78°  | 7 mph NNE |
| Mon 24   | Partly Cloudy Day   | 67°         | 67° | 85°  | 6 mph W   |
| Tue 25   | Partly Cloudy Day   | 69°         | 69° | 88°  | 7 mph W   |
| Wed 26   | Partly Cloudy Day   | 70°         | 70° | 88°  | 7 mph W   |
| Thu 27   | Partly Cloudy Day   | 67°         | 67° | 86°  | 7 mph WNW |
| Fri 28   | Partly Cloudy Day   | 66°         | 66° | 84°  | 7 mph NW  |

## Air Quality Index

**61**  
**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-CA/forecast/air-quality/l/38.97,-77.386)

## Health & Activities

- **Grass**  
  Seasonal Allergies and Pollen Count Forecast  
  Grass pollen is moderate in your area  
  [More info](/content/en-CA/forecast/allergy/l/5c8860db8e32112f6e30d296f4b629e2b5f377a5fb3ac887649b02aec9b79084/index.html)

- **Flu**  
  Cold & Flu Forecast  
  Flu risk is very low in your area  
  [More info](/content/en-CA/forecast/cold-flu/l/5c8860db8e32112f6e30d296f4b629e2b5f377a5fb3ac887649b02aec9b79084/index.html)