Boulder
United States · 20 May 2022
Average
0.6°C
low -2.9°C · high 5.2°C
Rainfall
21.3mm
rain recorded
Wind
1.8m/s
daily average
Humidity
92.5%
daily average
Cloud
88%
cover
Pressure
1013hPa
daily average
The temperature ranged from -2.9°C around 23:00 to 5.2°C around 00:00. Rain was recorded across 18 hours, from around 06:00 to 23:00 (21.3mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
4th percentile
Low temperature
1th percentile
Rainfall
99th percentile
Wind
37th 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 11.1°C, versus 0.6°C on this specific day.
Sun & daylight
Sunrise
05:41
Sunset
20:14
Day length
14h 33m
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 | 5.2°C | 1.6°C | 0 | 2.5 | ESE | 72 | 1003 |
| 01:00 | 07:00 | 3.6°C | 0.2°C | 0 | 2.3 | ESE | 81 | 1004 |
| 02:00 | 08:00 | 3.7°C | 0.1°C | 0.01 | 2.5 | SE | 82 | 1003 |
| 03:00 | 09:00 | 3.3°C | -0.3°C | 0 | 2.3 | SE | 79 | 1003 |
| 04:00 | 10:00 | 2.5°C | -0.8°C | 0 | 1.9 | ENE | 83 | 1006 |
| 05:00 | 11:00 | 2.2°C | -1.3°C | 0.07 | 2.1 | ESE | 85 | 1007 |
| 06:00 | 12:00 | 2.1°C | -1.1°C | 0.21 | 1.9 | SE | 87 | 1009 |
| 07:00 | 13:00 | 2°C | -1.1°C | 0.42 | 1.8 | SSE | 91 | 1009 |
| 08:00 | 14:00 | 1.4°C | -1.5°C | 0.59 | 1.5 | SSE | 95 | 1010 |
| 09:00 | 15:00 | 1.6°C | -1.1°C | 0.77 | 1.2 | SE | 94 | 1009 |
| 10:00 | 16:00 | 1.2°C | -1.6°C | 0.93 | 1.3 | ESE | 95 | 1010 |
| 11:00 | 17:00 | 0.7°C | -2.5°C | 1.06 | 1.6 | E | 94 | 1011 |
| 12:00 | 18:00 | 0.7°C | -2.5°C | 1.15 | 1.6 | ENE | 94 | 1013 |
| 13:00 | 19:00 | -0.4°C | -3.8°C | 2.24 | 1.9 | ENE | 96 | 1013 |
| 14:00 | 20:00 | -1.4°C | -4.9°C | 1.83 | 1.8 | E | 99 | 1014 |
| 15:00 | 21:00 | -1°C | -4.7°C | 1.41 | 2.1 | E | 100 | 1015 |
| 16:00 | 22:00 | -0.4°C | -3.5°C | 1.2 | 1.3 | ENE | 94 | 1017 |
| 17:00 | 23:00 | -1.2°C | -4.9°C | 1.3 | 2.2 | E | 99 | 1018 |
| 18:00 | 00:00 | -1.1°C | -5°C | 1.21 | 2.4 | E | 100 | 1019 |
| 19:00 | 01:00 | -1.4°C | -5°C | 1.2 | 2 | ESE | 100 | 1020 |
| 20:00 | 02:00 | -1.7°C | -4.8°C | 1.35 | 1.3 | ESE | 100 | 1021 |
| 21:00 | 03:00 | -2.3°C | -5.6°C | 1.52 | 1.3 | SE | 100 | 1022 |
| 22:00 | 04:00 | -2.4°C | -5.7°C | 1.49 | 1.4 | SSE | 100 | 1023 |
| 23:00 | 05:00 | -2.9°C | -6.2°C | 1.3 | 1.4 | S | 100 | 1024 |
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
- Boulder — 40.000°, -105.250°, ERA5 grid cell center, 2.4 km from requested point
- Time zone
- America/Denver
- What's shown here
- The hourly and daily record for 20 May 2022 specifically — not a monthly average. See the Boulder 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 Boulder, United States (40.00°N, 105.25°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Boulder, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 21, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Boulder, 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 Boulder, 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.