Potomac
United States · 7 July 2019
Average
26.6°C
low 23.7° · high 31°
Rainfall
4.7mm
rain recorded
Wind
1.6m/s
daily average
Humidity
79.5%
daily average
Cloud
92%
cover
Pressure
1012hPa
daily average
The temperature ranged from 23.7°C around 06:00 to 31°C around 17:00. Rain was recorded across 8 hours, from around 11:00 to 21:00 (4.7mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
32th percentile
Low temperature
80th percentile
Rainfall
76th percentile
Wind
14th percentile
A percentile of 100 means this was the hottest/wettest/windiest of the comparable days on file; 50 is right in the middle. This window's average temperature was 26.5°C, versus 26.6°C on this specific day.
Sun & daylight
Sunrise
05:50
Sunset
20:37
Day length
14h 47m
Hour by hour
Temperature (line) and hourly rainfall (bars), local time — America/New_York.
Cumulative rainfall through the day.
| Local time | UTC | Temp °C | Feels °C | Rain mm | Wind m/s | Dir | Humidity % | Pressure hPa |
|---|---|---|---|---|---|---|---|---|
| 00:00 | 04:00 | 24.9 | 28.9 | 0 | 1.3 | NW | 86 | 1013 |
| 01:00 | 05:00 | 24.5 | 28.2 | 0 | 1.6 | NW | 87 | 1012 |
| 02:00 | 06:00 | 24.4 | 28.1 | 0 | 1.7 | WNW | 89 | 1012 |
| 03:00 | 07:00 | 24.1 | 27.6 | 0 | 2 | NW | 89 | 1012 |
| 04:00 | 08:00 | 24.2 | 27.6 | 0 | 2 | NNW | 89 | 1012 |
| 05:00 | 09:00 | 24 | 27.5 | 0 | 2.1 | NNW | 91 | 1012 |
| 06:00 | 10:00 | 23.7 | 26.9 | 0 | 1.8 | N | 87 | 1012 |
| 07:00 | 11:00 | 24.1 | 27.2 | 0 | 2.1 | NNE | 87 | 1013 |
| 08:00 | 12:00 | 25.2 | 28.2 | 0 | 2.5 | NNE | 84 | 1013 |
| 09:00 | 13:00 | 26.5 | 29.6 | 0.05 | 2.8 | NNE | 79 | 1014 |
| 10:00 | 14:00 | 27.3 | 30.7 | 0.06 | 2.1 | NNE | 74 | 1013 |
| 11:00 | 15:00 | 27.9 | 31.6 | 0.13 | 1.1 | NE | 68 | 1013 |
| 12:00 | 16:00 | 28.1 | 32.5 | 0.16 | 0.5 | NNE | 70 | 1013 |
| 13:00 | 17:00 | 28.1 | 32.9 | 0.45 | 0.1 | NNE | 72 | 1013 |
| 14:00 | 18:00 | 28.4 | 33.9 | 0.91 | 0.2 | SW | 76 | 1013 |
| 15:00 | 19:00 | 29.8 | 35.6 | 0.03 | 0.5 | ESE | 73 | 1012 |
| 16:00 | 20:00 | 30.7 | 35.3 | 0.01 | 1.1 | E | 65 | 1011 |
| 17:00 | 21:00 | 31 | 36.2 | 0.06 | 1.5 | SE | 70 | 1011 |
| 18:00 | 22:00 | 28.4 | 32.9 | 1.86 | 1.5 | ESE | 75 | 1011 |
| 19:00 | 23:00 | 27.9 | 32.2 | 0.29 | 1.9 | E | 78 | 1011 |
| 20:00 | 00:00 | 27.5 | 31.4 | 0.2 | 1.8 | E | 76 | 1012 |
| 21:00 | 01:00 | 26.4 | 29.6 | 0.47 | 2.1 | ESE | 77 | 1012 |
| 22:00 | 02:00 | 25.8 | 29.1 | 0.03 | 2 | ESE | 79 | 1012 |
| 23:00 | 03:00 | 25 | 28.5 | 0 | 2.4 | ESE | 87 | 1012 |
Nearby cities
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Data source & coverage — ERA5 reanalysis, 2016–2025 (10 years)details
- Source
- ERA5 reanalysis, accessed via the Copernicus Climate Change Service (C3S) Climate Data Store
- Data type
- Reanalysis — a physically consistent reconstruction combining a forecast model with historical observations, not a live station reading or a forecast
- Coverage
- 2016–2025 (10 years) for United States
- Location
- Potomac — 39.000°, -77.250°, ERA5 grid cell center, 4.1 km from requested point
- Time zone
- America/New_York
- What's shown here
- The hourly and daily record for 7 July 2019 specifically — not a monthly average. See the Potomac climate overview for typical conditions.
- Spatial resolution
- 0.25° (~25 km) distributed grid — ERA5's native model resolution is finer; this is the publicly distributed regridded product
- Version / refreshed
- Methodology v2026.07 · data last refreshed December 31, 2025
- Limitations
- A model reconstruction, not a station observation — hyper-local extremes (a single storm cell, an urban heat pocket) can differ from a nearby gauge. See the full methodology.
- Attribution
- Generated using Copernicus Climate Change Service information
Cite this data
PastClimate (2026-07-17). Historical climate data for Potomac, United States (39.00°N, 77.25°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Potomac, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 17, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Potomac, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 17, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Potomac, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-17},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.