Home / Keystone / 21 September 2017
Keystone
United States · 21 September 2017
← 20 September 201722 September 2017 →
Average
27.2°C
low 22.4°C · high 32°C
Rainfall
0.1mm
dry day
Wind
2.1m/s
daily average
Humidity
69.4%
daily average
Cloud
30%
cover
Pressure
1015hPa
daily average
The temperature ranged from 22.4°C around 06:00 to 32°C around 14:00. No measurable rain was recorded during the day.
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
57th percentile
Low temperature
22th percentile
Rainfall
20th percentile
Wind
52th 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 26.9°C, versus 27.2°C on this specific day.
Sun & daylight
Sunrise
07:18
Sunset
19:27
Day length
12h 9m
Hour by hour
Temperature (line) and hourly rainfall (bars), local time — America/New_York.
Cumulative rainfall through the day.
| Local time | UTC | Temp | Feels | Rain mm | Wind m/s | Dir | Humidity % | Pressure hPa |
|---|---|---|---|---|---|---|---|---|
| 00:00 | 04:00 | 25.6°C | 28.1°C | 0 | 2.4 | ESE | 76 | 1016 |
| 01:00 | 05:00 | 24.9°C | 27.5°C | 0 | 2.3 | E | 79 | 1016 |
| 02:00 | 06:00 | 24.6°C | 27.4°C | 0 | 1.9 | E | 80 | 1016 |
| 03:00 | 07:00 | 23.9°C | 26.7°C | 0 | 1.9 | E | 83 | 1015 |
| 04:00 | 08:00 | 23.3°C | 26.2°C | 0 | 1.8 | E | 87 | 1015 |
| 05:00 | 09:00 | 22.9°C | 25.6°C | 0 | 1.9 | E | 88 | 1015 |
| 06:00 | 10:00 | 22.4°C | 25.2°C | 0 | 1.6 | E | 90 | 1015 |
| 07:00 | 11:00 | 22.5°C | 25.5°C | 0 | 1.5 | E | 90 | 1015 |
| 08:00 | 12:00 | 22.5°C | 25.3°C | 0 | 1.8 | ENE | 90 | 1016 |
| 09:00 | 13:00 | 24.5°C | 28.3°C | 0 | 1.4 | ENE | 87 | 1016 |
| 10:00 | 14:00 | 26.9°C | 31.2°C | 0 | 1.4 | ENE | 80 | 1017 |
| 11:00 | 15:00 | 29.1°C | 32.1°C | 0 | 1.5 | NE | 61 | 1016 |
| 12:00 | 16:00 | 30.5°C | 33.4°C | 0 | 1.6 | NE | 56 | 1016 |
| 13:00 | 17:00 | 31.9°C | 34.1°C | 0.02 | 2.4 | NE | 51 | 1016 |
| 14:00 | 18:00 | 32°C | 34.1°C | 0.03 | 2.6 | NE | 51 | 1015 |
| 15:00 | 19:00 | 31.8°C | 33.7°C | 0 | 2.7 | NE | 51 | 1014 |
| 16:00 | 20:00 | 31.4°C | 32.9°C | 0 | 2.8 | NE | 49 | 1013 |
| 17:00 | 21:00 | 31.2°C | 32.7°C | 0 | 3 | NE | 51 | 1013 |
| 18:00 | 22:00 | 30.6°C | 32.7°C | 0.07 | 2.5 | NE | 55 | 1013 |
| 19:00 | 23:00 | 29.5°C | 31.8°C | 0 | 2.1 | NNE | 57 | 1013 |
| 20:00 | 00:00 | 28.6°C | 30.8°C | 0 | 2 | NE | 59 | 1013 |
| 21:00 | 01:00 | 27.9°C | 29.8°C | 0 | 2.4 | ENE | 61 | 1014 |
| 22:00 | 02:00 | 27.5°C | 29.2°C | 0 | 2.8 | ENE | 63 | 1015 |
| 23:00 | 03:00 | 26.6°C | 28.6°C | 0 | 2.9 | E | 70 | 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
- Keystone — 28.250°, -82.500°, ERA5 grid cell center, 15.8 km from requested point
- Time zone
- America/New_York
- What's shown here
- The hourly and daily record for 21 September 2017 specifically — not a monthly average. See the Keystone 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 (2026-07-21). Historical climate data for Keystone, United States (28.25°N, 82.50°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Keystone, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 21, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Keystone, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 21, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Keystone, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-21},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.