Potomac
United States · 10 July 2017
Average
25.7°C
low 19.8° · high 32.2°
Rainfall
0.1mm
dry day
Wind
2.3m/s
daily average
Humidity
65.7%
daily average
Cloud
42%
cover
Pressure
1017hPa
daily average
The temperature ranged from 19.8°C around 06:00 to 32.2°C around 17:00. Rain was recorded for one hour, around 12:00 (0.1mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
50th percentile
Low temperature
15th percentile
Rainfall
36th percentile
Wind
63th 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 26.8°C, versus 25.7°C on this specific day.
Sun & daylight
Sunrise
05:52
Sunset
20:36
Day length
14h 44m
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 | 21.1 | 21.3 | 0 | 2.1 | E | 70 | 1018 |
| 01:00 | 05:00 | 20.6 | 21 | 0 | 2.2 | ESE | 74 | 1018 |
| 02:00 | 06:00 | 20.6 | 21.2 | 0 | 2 | ESE | 76 | 1018 |
| 03:00 | 07:00 | 20.5 | 21.6 | 0 | 1.7 | ESE | 79 | 1018 |
| 04:00 | 08:00 | 20.2 | 21.4 | 0 | 1.8 | ESE | 82 | 1018 |
| 05:00 | 09:00 | 19.9 | 21.1 | 0 | 2.1 | SE | 87 | 1017 |
| 06:00 | 10:00 | 19.8 | 21.6 | 0 | 1.2 | S | 89 | 1017 |
| 07:00 | 11:00 | 20.3 | 21.9 | 0 | 2 | S | 89 | 1017 |
| 08:00 | 12:00 | 22 | 24.3 | 0 | 1.6 | SW | 86 | 1018 |
| 09:00 | 13:00 | 23.9 | 26.9 | 0 | 1.7 | WSW | 85 | 1018 |
| 10:00 | 14:00 | 25.3 | 28.7 | 0 | 1.5 | WSW | 79 | 1018 |
| 11:00 | 15:00 | 28.1 | 30.3 | 0.04 | 1.4 | SW | 57 | 1018 |
| 12:00 | 16:00 | 28.5 | 30 | 0.1 | 2 | SW | 54 | 1018 |
| 13:00 | 17:00 | 29.8 | 30.8 | 0 | 2.6 | SSW | 50 | 1017 |
| 14:00 | 18:00 | 30.5 | 31 | 0 | 3 | SW | 46 | 1016 |
| 15:00 | 19:00 | 31.4 | 31.6 | 0 | 3.1 | SW | 42 | 1016 |
| 16:00 | 20:00 | 31.9 | 32.1 | 0 | 3 | SW | 41 | 1015 |
| 17:00 | 21:00 | 32.2 | 33.5 | 0 | 2.6 | SW | 44 | 1015 |
| 18:00 | 22:00 | 31.9 | 33.2 | 0 | 2.5 | SW | 45 | 1014 |
| 19:00 | 23:00 | 30.1 | 32.1 | 0 | 1.9 | S | 52 | 1014 |
| 20:00 | 00:00 | 28.6 | 29.9 | 0 | 2.6 | SSE | 55 | 1014 |
| 21:00 | 01:00 | 27.6 | 28.7 | 0 | 2.9 | SSE | 58 | 1014 |
| 22:00 | 02:00 | 27.1 | 28.2 | 0 | 3.2 | S | 62 | 1015 |
| 23:00 | 03:00 | 25.5 | 27.3 | 0 | 3.3 | SSW | 75 | 1015 |
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 10 July 2017 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.