Home / Aurora / 21 September 2017
Aurora
United States · 21 September 2017
← 20 September 201722 September 2017 →
Average
23.7°C
low 15.2°C · high 32.8°C
Rainfall
0mm
dry day
Wind
5.8m/s
daily average
Humidity
18.5%
daily average
Cloud
0%
cover
Pressure
1000hPa
daily average
The temperature ranged from 15.2°C around 04:00 to 32.8°C around 15:00. 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
93th percentile
Low temperature
87th percentile
Rainfall
67th percentile
Wind
99th 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 19°C, versus 23.7°C on this specific day.
Sun & daylight
Sunrise
06:45
Sunset
18:57
Day length
12h 11m
Hour by hour
Temperature (line) and hourly rainfall (bars), local time — America/Denver.
Cumulative rainfall through the day.
| Local time | UTC | Temp | Feels | Rain mm | Wind m/s | Dir | Humidity % | Pressure hPa |
|---|---|---|---|---|---|---|---|---|
| 00:00 | 06:00 | 16.2°C | 9.5°C | 0 | 6.7 | S | 33 | 1004 |
| 01:00 | 07:00 | 16°C | 9.7°C | 0 | 6.2 | S | 34 | 1004 |
| 02:00 | 08:00 | 16.3°C | 10.2°C | 0 | 5.8 | SSW | 32 | 1004 |
| 03:00 | 09:00 | 15.6°C | 9.8°C | 0 | 5.5 | SSW | 34 | 1003 |
| 04:00 | 10:00 | 15.2°C | 8.5°C | 0 | 6.8 | S | 35 | 1002 |
| 05:00 | 11:00 | 16°C | 9.3°C | 0 | 6.5 | S | 31 | 1002 |
| 06:00 | 12:00 | 16°C | 9.8°C | 0 | 5.8 | S | 31 | 1003 |
| 07:00 | 13:00 | 16.1°C | 10.1°C | 0 | 5.4 | SSW | 30 | 1003 |
| 08:00 | 14:00 | 18°C | 12°C | 0 | 5.4 | SSW | 27 | 1003 |
| 09:00 | 15:00 | 23°C | 16.9°C | 0 | 4.9 | SSW | 15 | 1003 |
| 10:00 | 16:00 | 26.4°C | 20.3°C | 0 | 5 | SSW | 12 | 1002 |
| 11:00 | 17:00 | 28.9°C | 22.5°C | 0 | 5 | SSW | 8 | 1001 |
| 12:00 | 18:00 | 29.9°C | 24.2°C | 0 | 4.2 | SSW | 8 | 999 |
| 13:00 | 19:00 | 30.3°C | 25.1°C | 0 | 3.6 | SSW | 9 | 999 |
| 14:00 | 20:00 | 31.5°C | 26.5°C | 0 | 3.3 | S | 8 | 998 |
| 15:00 | 21:00 | 32.8°C | 27.5°C | 0 | 3.5 | S | 7 | 996 |
| 16:00 | 22:00 | 32.2°C | 25.5°C | 0 | 5.6 | S | 8 | 995 |
| 17:00 | 23:00 | 32.1°C | 25°C | 0 | 6.1 | S | 8 | 994 |
| 18:00 | 00:00 | 31.4°C | 24.1°C | 0 | 6.4 | S | 7 | 995 |
| 19:00 | 01:00 | 29.2°C | 21°C | 0 | 7.6 | S | 8 | 996 |
| 20:00 | 02:00 | 26.3°C | 18°C | 0 | 8.1 | S | 12 | 996 |
| 21:00 | 03:00 | 23.6°C | 15.7°C | 0 | 7.7 | S | 16 | 997 |
| 22:00 | 04:00 | 23.4°C | 15.5°C | 0 | 7.6 | SSW | 15 | 997 |
| 23:00 | 05:00 | 23°C | 15.3°C | 0 | 7.3 | SSW | 15 | 998 |
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
- Aurora — 39.750°, -104.750°, ERA5 grid cell center, 7.4 km from requested point
- Time zone
- America/Denver
- What's shown here
- The hourly and daily record for 21 September 2017 specifically — not a monthly average. See the Aurora 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 (2026-07-20). Historical climate data for Aurora, United States (39.75°N, 104.75°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Aurora, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 20, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Aurora, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 20, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Aurora, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-20},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.