Herndon weather in July
In July, Herndon sees average daytime highs of 88°F and overnight lows near 69°F, with 3.9 in of rain across 11.8 wet days and about 14.5 hours of daylight. It is the 1st-warmest and 2nd-wettest month of the year here.
Day-to-day highs hold fairly steady near 88°F through the month. The sky is clear or mostly clear about 28% of the time in July, and the air most often feels muggy.
Daylight stretches from about 14 h 42 min at the start of July to 14 h 06 min by month's end. Set against the rest of the year, July is Herndon's 5th-clearest and 11th-windiest month. For the whole year in context, see Herndon's year-round climate.
- Daytime high
- 88°
- 1st warmest
- Overnight low
- 69°
- 12th coldest
- Rainfall
- 3.9 in
- 11.8 wet days
- Daylight
- 14 h 30 min
- 5:01 AM – 7:30 PM
- Cloud cover
- 59%
- 5th clearest
- Wind
- 5 mph
- 11th windiest
- Solar energy
- 5.99 kWh/m²
- Travel score
- 4.4
- out of 10
Herndon is town in Virginia, United States.
- Density
- 2,216/km²
- people per km²
- Founded
- 1858
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in July
Day-to-day highs hold fairly steady near 88°F through the month.
A typical July day in Herndon reaches about 88°F in the afternoon and slips back to 69°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 80°F and 95°F. Set against its neighbours, July runs about 4°F warmer than June and about 2°F warmer than August.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 87 | 87 | 87 | 87 | 87 | 87 | 87 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 88 | 87 | 87 | 87 | 87 | 87 | 87 |
| Avg low (°F) | 68 | 68 | 69 | 69 | 69 | 69 | 69 | 69 | 69 | 69 | 69 | 69 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 | 70 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 87 | 68 |
| 2 | 87 | 68 |
| 3 | 87 | 69 |
| 4 | 87 | 69 |
| 5 | 87 | 69 |
| 6 | 87 | 69 |
| 7 | 87 | 69 |
| 8 | 88 | 69 |
| 9 | 88 | 69 |
| 10 | 88 | 69 |
| 11 | 88 | 69 |
| 12 | 88 | 69 |
| 13 | 88 | 70 |
| 14 | 88 | 70 |
| 15 | 88 | 70 |
| 16 | 88 | 70 |
| 17 | 88 | 70 |
| 18 | 88 | 70 |
| 19 | 88 | 70 |
| 20 | 88 | 70 |
| 21 | 88 | 70 |
| 22 | 88 | 70 |
| 23 | 88 | 70 |
| 24 | 88 | 70 |
| 25 | 88 | 70 |
| 26 | 87 | 70 |
| 27 | 87 | 70 |
| 28 | 87 | 70 |
| 29 | 87 | 70 |
| 30 | 87 | 70 |
| 31 | 87 | 70 |
How July really feels in Herndon
Once humidity and wind are folded in, July averages 8 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.
The story in July is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Herndon weather by month
How July compares with the rest of the year at a glance. July is the 1st-warmest and 2nd-wettest month here — the current month is highlighted below.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 42° / 28° | 3.0 | 8.6 | 3 | 9.6 | 0.3 |
| Feb | 45° / 29° | 2.8 | 8.1 | 3 | 10.5 | 1.1 |
| Mar | 54° / 36° | 3.8 | 10 | 2 | 11.7 | 3.3 |
| Apr | 66° / 46° | 3.4 | 10.3 | 0.1 | 13 | 5.8 |
| May | 74° / 56° | 3.8 | 11.3 | 0 | 14.1 | 6.5 |
| Jun | 83° / 65° | 3.4 | 11.2 | 0 | 14.7 | 5.5 |
| Jul | 88° / 69° | 3.9 | 11.8 | 0 | 14.5 | 4.4 |
| Aug | 85° / 68° | 3.3 | 10.4 | 0 | 13.5 | 5.1 |
| Sep | 78° / 60° | 4.4 | 9.5 | 0 | 12.3 | 6.7 |
| Oct | 67° / 49° | 3.4 | 7.8 | 0 | 11 | 6.5 |
| Nov | 55° / 38° | 3.0 | 7.6 | 0.3 | 9.9 | 3.9 |
| Dec | 46° / 32° | 3.5 | 9.1 | 2.1 | 9.3 | 1.3 |
Cloud cover in July
The sky is clear or mostly clear about 28% of the time in July.
Beyond those clear spells, partly cloudy skies cover about 22% of July, with mostly cloudy or overcast conditions the remaining 50%.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 50 | 50 | 51 | 50 | 50 | 51 | 51 | 51 | 52 | 52 | 53 | 53 | 53 | 53 | 53 | 51 | 51 | 51 | 50 | 50 | 49 | 49 | 48 | 48 | 48 | 48 | 49 | 48 | 48 | 48 | 48 |
| Cloudier (%) | 50 | 50 | 49 | 50 | 50 | 49 | 49 | 49 | 48 | 48 | 47 | 47 | 47 | 47 | 47 | 49 | 49 | 49 | 50 | 50 | 51 | 51 | 52 | 52 | 52 | 52 | 51 | 52 | 52 | 52 | 52 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 50 | 50 |
| 2 | 50 | 50 |
| 3 | 51 | 49 |
| 4 | 50 | 50 |
| 5 | 50 | 50 |
| 6 | 51 | 49 |
| 7 | 51 | 49 |
| 8 | 51 | 49 |
| 9 | 52 | 48 |
| 10 | 52 | 48 |
| 11 | 53 | 47 |
| 12 | 53 | 47 |
| 13 | 53 | 47 |
| 14 | 53 | 47 |
| 15 | 53 | 47 |
| 16 | 51 | 49 |
| 17 | 51 | 49 |
| 18 | 51 | 49 |
| 19 | 50 | 50 |
| 20 | 50 | 50 |
| 21 | 49 | 51 |
| 22 | 49 | 51 |
| 23 | 48 | 52 |
| 24 | 48 | 52 |
| 25 | 48 | 52 |
| 26 | 48 | 52 |
| 27 | 49 | 51 |
| 28 | 48 | 52 |
| 29 | 48 | 52 |
| 30 | 48 | 52 |
| 31 | 48 | 52 |
Chance of precipitation in July
Herndon gets around 3.9 in of rain over 11.8 wet days in July. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 38% and peaks near 41% on the wettest days.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 38 | 38 | 38 | 37 | 37 | 37 | 36 | 36 | 36 | 35 | 35 | 35 | 35 | 35 | 36 | 36 | 37 | 37 | 38 | 39 | 39 | 39 | 40 | 40 | 40 | 41 | 41 | 41 | 40 | 40 | 39 |
| Rain chance (%) | |
|---|---|
| 1 | 38 |
| 2 | 38 |
| 3 | 38 |
| 4 | 37 |
| 5 | 37 |
| 6 | 37 |
| 7 | 36 |
| 8 | 36 |
| 9 | 36 |
| 10 | 35 |
| 11 | 35 |
| 12 | 35 |
| 13 | 35 |
| 14 | 35 |
| 15 | 36 |
| 16 | 36 |
| 17 | 37 |
| 18 | 37 |
| 19 | 38 |
| 20 | 39 |
| 21 | 39 |
| 22 | 39 |
| 23 | 40 |
| 24 | 40 |
| 25 | 40 |
| 26 | 41 |
| 27 | 41 |
| 28 | 41 |
| 29 | 40 |
| 30 | 40 |
| 31 | 39 |
Humidity in July
Most of July feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, July lands in the muggy band about 36% of days. Sticky, muggy-or-worse air turns up on roughly 53% of them.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 13 | 13 | 13 | 13 | 13 | 13 | 12 | 12 | 12 | 11 | 11 | 10 | 10 | 9 | 9 | 8 | 8 | 8 | 7 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 7 | 7 | 7 |
| Comfortable (%) | 17 | 16 | 15 | 15 | 14 | 14 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Humid (%) | 23 | 23 | 23 | 23 | 24 | 24 | 24 | 25 | 25 | 25 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 26 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| Muggy (%) | 33 | 33 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 34 | 35 | 35 | 35 | 35 | 35 | 36 | 36 | 36 | 36 | 36 | 37 | 37 | 37 | 37 | 38 | 38 | 38 | 38 | 37 | 37 |
| Oppressive (%) | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 17 | 18 | 18 | 19 | 19 | 20 | 20 | 20 | 21 | 21 | 21 | 21 | 20 | 20 | 20 | 19 | 19 | 19 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | |
|---|---|---|---|---|---|
| 1 | 13 | 17 | 23 | 33 | 14 |
| 2 | 13 | 16 | 23 | 33 | 14 |
| 3 | 13 | 15 | 23 | 34 | 15 |
| 4 | 13 | 15 | 23 | 34 | 15 |
| 5 | 13 | 14 | 24 | 34 | 15 |
| 6 | 13 | 14 | 24 | 34 | 16 |
| 7 | 12 | 13 | 24 | 34 | 16 |
| 8 | 12 | 13 | 25 | 34 | 16 |
| 9 | 12 | 13 | 25 | 34 | 16 |
| 10 | 11 | 12 | 25 | 34 | 17 |
| 11 | 11 | 12 | 26 | 34 | 17 |
| 12 | 10 | 12 | 26 | 35 | 17 |
| 13 | 10 | 12 | 26 | 35 | 17 |
| 14 | 9 | 12 | 26 | 35 | 17 |
| 15 | 9 | 12 | 26 | 35 | 18 |
| 16 | 8 | 12 | 26 | 35 | 18 |
| 17 | 8 | 11 | 26 | 36 | 19 |
| 18 | 8 | 11 | 26 | 36 | 19 |
| 19 | 7 | 11 | 26 | 36 | 20 |
| 20 | 7 | 11 | 26 | 36 | 20 |
| 21 | 6 | 11 | 26 | 36 | 20 |
| 22 | 6 | 11 | 26 | 37 | 21 |
| 23 | 6 | 11 | 25 | 37 | 21 |
| 24 | 6 | 11 | 25 | 37 | 21 |
| 25 | 6 | 11 | 25 | 37 | 21 |
| 26 | 6 | 11 | 25 | 38 | 20 |
| 27 | 6 | 11 | 25 | 38 | 20 |
| 28 | 6 | 11 | 25 | 38 | 20 |
| 29 | 7 | 11 | 25 | 38 | 19 |
| 30 | 7 | 11 | 25 | 37 | 19 |
| 31 | 7 | 11 | 25 | 37 | 19 |
Wind in July
Winds average 5 mph in July.
Across July, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 5 | calm |
| 2 | 5 | calm |
| 3 | 5 | calm |
| 4 | 5 | calm |
| 5 | 5 | calm |
| 6 | 5 | calm |
| 7 | 5 | calm |
| 8 | 5 | calm |
| 9 | 5 | calm |
| 10 | 5 | calm |
| 11 | 5 | calm |
| 12 | 5 | calm |
| 13 | 5 | calm |
| 14 | 5 | calm |
| 15 | 5 | calm |
| 16 | 5 | calm |
| 17 | 5 | calm |
| 18 | 5 | calm |
| 19 | 5 | calm |
| 20 | 5 | calm |
| 21 | 5 | calm |
| 22 | 5 | calm |
| 23 | 5 | calm |
| 24 | 5 | calm |
| 25 | 5 | calm |
| 26 | 5 | calm |
| 27 | 5 | calm |
| 28 | 5 | calm |
| 29 | 5 | calm |
| 30 | 5 | calm |
| 31 | 5 | calm |
Sunrise & sunset in July
Daylight runs from about 14 h 42 min at the start of July to 14 h 06 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 36 minutes over July. Sunrise moves from 4:52 AM to 5:13 AM, and sunset from 7:34 PM to 7:18 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 14.7 | 14.7 | 14.7 | 14.7 | 14.7 | 14.7 | 14.6 | 14.6 | 14.6 | 14.6 | 14.6 | 14.6 | 14.5 | 14.5 | 14.5 | 14.5 | 14.5 | 14.4 | 14.4 | 14.4 | 14.4 | 14.3 | 14.3 | 14.3 | 14.3 | 14.2 | 14.2 | 14.2 | 14.2 | 14.1 | 14.1 |
| Sunrise (AM) | 4:52 | 4:52 | 4:53 | 4:53 | 4:54 | 4:54 | 4:55 | 4:55 | 4:56 | 4:57 | 4:57 | 4:58 | 4:59 | 4:59 | 5:00 | 5:01 | 5:01 | 5:02 | 5:03 | 5:04 | 5:04 | 5:05 | 5:06 | 5:07 | 5:08 | 5:09 | 5:09 | 5:10 | 5:11 | 5:12 | 5:13 |
| Sunset (PM) | 7:34 | 7:34 | 7:34 | 7:34 | 7:34 | 7:33 | 7:33 | 7:33 | 7:33 | 7:32 | 7:32 | 7:32 | 7:31 | 7:31 | 7:30 | 7:30 | 7:29 | 7:29 | 7:28 | 7:27 | 7:27 | 7:26 | 7:25 | 7:24 | 7:24 | 7:23 | 7:22 | 7:21 | 7:20 | 7:19 | 7:18 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 14.7 | 4:52 | 7:34 |
| 2 | 14.7 | 4:52 | 7:34 |
| 3 | 14.7 | 4:53 | 7:34 |
| 4 | 14.7 | 4:53 | 7:34 |
| 5 | 14.7 | 4:54 | 7:34 |
| 6 | 14.7 | 4:54 | 7:33 |
| 7 | 14.6 | 4:55 | 7:33 |
| 8 | 14.6 | 4:55 | 7:33 |
| 9 | 14.6 | 4:56 | 7:33 |
| 10 | 14.6 | 4:57 | 7:32 |
| 11 | 14.6 | 4:57 | 7:32 |
| 12 | 14.6 | 4:58 | 7:32 |
| 13 | 14.5 | 4:59 | 7:31 |
| 14 | 14.5 | 4:59 | 7:31 |
| 15 | 14.5 | 5:00 | 7:30 |
| 16 | 14.5 | 5:01 | 7:30 |
| 17 | 14.5 | 5:01 | 7:29 |
| 18 | 14.4 | 5:02 | 7:29 |
| 19 | 14.4 | 5:03 | 7:28 |
| 20 | 14.4 | 5:04 | 7:27 |
| 21 | 14.4 | 5:04 | 7:27 |
| 22 | 14.3 | 5:05 | 7:26 |
| 23 | 14.3 | 5:06 | 7:25 |
| 24 | 14.3 | 5:07 | 7:24 |
| 25 | 14.3 | 5:08 | 7:24 |
| 26 | 14.2 | 5:09 | 7:23 |
| 27 | 14.2 | 5:09 | 7:22 |
| 28 | 14.2 | 5:10 | 7:21 |
| 29 | 14.2 | 5:11 | 7:20 |
| 30 | 14.1 | 5:12 | 7:19 |
| 31 | 14.1 | 5:13 | 7:18 |
Solar energy in July
Average shortwave solar energy reaching the ground each day in July, about 5.99 kWh/m².
For context, solar energy here swings from a low near 1.95 kWh/m² to a high of 6.15 kWh/m² in June across the year — July's 5.99 kWh/m² sits near the top of that range.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 6.3 | 6.3 | 6.3 | 6.3 | 6.3 | 6.2 | 6.2 | 6.2 | 6.2 | 6.2 | 6.2 | 6.2 | 6.2 | 6.1 | 6.1 | 6.1 | 6.0 | 6.0 | 6.0 | 6.0 | 5.9 | 5.9 | 5.8 | 5.8 | 5.8 | 5.8 | 5.7 | 5.7 | 5.7 | 5.7 | 5.6 |
| Level | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 6.3 | Intense |
| 2 | 6.3 | Intense |
| 3 | 6.3 | Intense |
| 4 | 6.3 | Intense |
| 5 | 6.3 | Intense |
| 6 | 6.2 | Intense |
| 7 | 6.2 | Intense |
| 8 | 6.2 | Intense |
| 9 | 6.2 | Intense |
| 10 | 6.2 | Intense |
| 11 | 6.2 | Intense |
| 12 | 6.2 | Intense |
| 13 | 6.2 | Intense |
| 14 | 6.1 | Intense |
| 15 | 6.1 | Intense |
| 16 | 6.1 | Intense |
| 17 | 6.0 | Intense |
| 18 | 6.0 | Intense |
| 19 | 6.0 | Bright |
| 20 | 6.0 | Bright |
| 21 | 5.9 | Bright |
| 22 | 5.9 | Bright |
| 23 | 5.8 | Bright |
| 24 | 5.8 | Bright |
| 25 | 5.8 | Bright |
| 26 | 5.8 | Bright |
| 27 | 5.7 | Bright |
| 28 | 5.7 | Bright |
| 29 | 5.7 | Bright |
| 30 | 5.7 | Bright |
| 31 | 5.6 | Bright |
Is July a good time to visit Herndon?
Our two travel scores rate July for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
July is a reasonable time to visit Herndon for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Herndon in July
From July's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In July, Herndon sees daytime highs around 88°F and nights near 69°F. Pack light clothes. Worth having: rain gear and sun protection. About 12 days see rain.
UV index in Herndon in July
Clear-sky midday UV in July peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Herndon peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 5 | 6 | 8 | 9 | 9 | 7 | 6 | 4 | 3 | 2 |
| Level | Moderate | Moderate | High | High | Very high | Very high | Very high | High | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Moderate |
| Feb | 3 | Moderate |
| Mar | 5 | High |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 7 | High |
| Sep | 6 | High |
| Oct | 4 | Moderate |
| Nov | 3 | Moderate |
| Dec | 2 | Low |
Air quality in Herndon in July
Average fine-particle pollution (PM2.5) through the year — so you can see where July falls, not just the annual average.
Air quality in Herndon is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 9 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 11 | 12 | 13 | 13 | 15 | 16 | 17 | 15 | 12 | 9 | 9 | 10 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 12 | Moderate |
| Mar | 13 | Moderate |
| Apr | 13 | Moderate |
| May | 15 | Moderate |
| Jun | 16 | Moderate |
| Jul | 17 | Moderate |
| Aug | 15 | Moderate |
| Sep | 12 | Moderate |
| Oct | 9 | Good |
| Nov | 9 | Good |
| Dec | 10 | Good |
Where is Herndon?
Herndon sits at 39.0°N, 77.4°W, 361 ft above sea level, in United States. The nearest listed city is Reston, 2.5 mi away.
Topography around Herndon
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Herndon.
Within 2 miles, the terrain around Herndon has only modest variations in elevation — a maximum elevation change of 505 ft around an average of 377 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 558 ft; within 50 miles, large variations in elevation — a maximum elevation change of 3,615 ft.
The land around Herndon is covered by trees (57%) and artificial surfaces (35%) within 2 miles, trees (67%) within 10 miles, and trees (65%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Herndon (38.9695°, -77.3861°, elevation 361 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).