Home / Cornwall / 4 September 2021
Cornwall
United States · 4 September 2021
← 3 September 20215 September 2021 →
Average
19.4°C
low 13.6°C · high 25.7°C
Rainfall
0mm
dry day
Wind
1.4m/s
daily average
Humidity
70.1%
daily average
Cloud
42%
cover
Pressure
1017hPa
daily average
The temperature ranged from 13.6°C around 04:00 to 25.7°C around 17:00. 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
33th percentile
Low temperature
19th percentile
Rainfall
52th percentile
Wind
5th 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 22°C, versus 19.4°C on this specific day.
Sun & daylight
Sunrise
06:36
Sunset
19:32
Day length
12h 56m
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 | 15.6°C | 15.9°C | 0 | 0.8 | NNW | 84 | 1019 |
| 01:00 | 05:00 | 14.7°C | 14.7°C | 0 | 1 | N | 85 | 1019 |
| 02:00 | 06:00 | 14.1°C | 14°C | 0 | 1 | NNE | 88 | 1018 |
| 03:00 | 07:00 | 13.7°C | 13.7°C | 0 | 0.8 | N | 89 | 1018 |
| 04:00 | 08:00 | 13.6°C | 13.6°C | 0 | 0.9 | NNW | 90 | 1018 |
| 05:00 | 09:00 | 14.1°C | 14.2°C | 0 | 1 | NNW | 89 | 1018 |
| 06:00 | 10:00 | 14.2°C | 14.1°C | 0 | 1.2 | NNE | 90 | 1019 |
| 07:00 | 11:00 | 14.1°C | 14.2°C | 0 | 1 | N | 90 | 1019 |
| 08:00 | 12:00 | 15.7°C | 16.1°C | 0 | 1 | N | 86 | 1019 |
| 09:00 | 13:00 | 17.2°C | 18.2°C | 0 | 0.2 | NNW | 78 | 1019 |
| 10:00 | 14:00 | 18.8°C | 19.8°C | 0 | 0.3 | WNW | 72 | 1019 |
| 11:00 | 15:00 | 21.9°C | 22.7°C | 0 | 0.6 | W | 60 | 1019 |
| 12:00 | 16:00 | 23.1°C | 23.5°C | 0 | 1.1 | W | 55 | 1018 |
| 13:00 | 17:00 | 23.6°C | 23.6°C | 0 | 1.3 | W | 51 | 1017 |
| 14:00 | 18:00 | 24.3°C | 24.1°C | 0 | 1.4 | WSW | 48 | 1016 |
| 15:00 | 19:00 | 24.8°C | 24.6°C | 0 | 1.6 | SW | 47 | 1015 |
| 16:00 | 20:00 | 25.4°C | 25.1°C | 0 | 1.8 | SW | 46 | 1015 |
| 17:00 | 21:00 | 25.7°C | 25.3°C | 0 | 1.9 | SSW | 46 | 1014 |
| 18:00 | 22:00 | 24.8°C | 24.8°C | 0 | 1.6 | SSW | 51 | 1014 |
| 19:00 | 23:00 | 23.5°C | 24°C | 0 | 1.3 | SSE | 58 | 1014 |
| 20:00 | 00:00 | 21.8°C | 21.8°C | 0 | 1.9 | SSE | 62 | 1014 |
| 21:00 | 01:00 | 20.9°C | 20.4°C | 0 | 2.7 | SSE | 67 | 1014 |
| 22:00 | 02:00 | 20.2°C | 19.7°C | 0 | 3 | SSE | 71 | 1014 |
| 23:00 | 03:00 | 19.2°C | 18.6°C | 0 | 3.1 | S | 77 | 1014 |
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
- Cornwall — 40.250°, -76.500°, ERA5 grid cell center, 8.4 km from requested point
- Time zone
- America/New_York
- What's shown here
- The hourly and daily record for 4 September 2021 specifically — not a monthly average. See the Cornwall 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 (2026-07-19). Historical climate data for Cornwall, United States (40.25°N, 76.50°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Cornwall, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 19, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Cornwall, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 19, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Cornwall, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-19},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.