Boulder
United States · 19 May 2023
Average
9.5°C
low 8.4°C · high 11.6°C
Rainfall
8mm
rain recorded
Wind
1.9m/s
daily average
Humidity
87.3%
daily average
Cloud
98%
cover
Pressure
1024hPa
daily average
The temperature ranged from 8.4°C around 10:00 to 11.6°C around 14:00. Rain was recorded across 17 hours, from around 00:00 to 18:00 (8mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
13th percentile
Low temperature
99th percentile
Rainfall
85th 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 10.7°C, versus 9.5°C on this specific day.
Sun & daylight
Sunrise
05:42
Sunset
20:13
Day length
14h 31m
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 | 8.6°C | 7.4°C | 0.79 | 0.7 | SSW | 91 | 1022 |
| 01:00 | 07:00 | 8.8°C | 7.8°C | 0.56 | 0.5 | WSW | 90 | 1022 |
| 02:00 | 08:00 | 8.6°C | 7.6°C | 0.66 | 0.6 | WSW | 92 | 1022 |
| 03:00 | 09:00 | 8.4°C | 7.3°C | 0.5 | 0.7 | WSW | 92 | 1022 |
| 04:00 | 10:00 | 8.9°C | 7.4°C | 0.42 | 1.4 | W | 92 | 1022 |
| 05:00 | 11:00 | 9.1°C | 7.6°C | 0.35 | 1.2 | NW | 90 | 1022 |
| 06:00 | 12:00 | 8.9°C | 6.8°C | 0.18 | 2 | NNW | 89 | 1023 |
| 07:00 | 13:00 | 8.9°C | 6.8°C | 0.08 | 2.1 | N | 90 | 1024 |
| 08:00 | 14:00 | 9°C | 6.6°C | 0.08 | 2.6 | NNE | 88 | 1025 |
| 09:00 | 15:00 | 9.1°C | 6.3°C | 0.16 | 3.1 | NNE | 88 | 1026 |
| 10:00 | 16:00 | 8.4°C | 5.2°C | 0.29 | 3.4 | NE | 90 | 1026 |
| 11:00 | 17:00 | 9.5°C | 6.7°C | 0.34 | 3.2 | ENE | 88 | 1027 |
| 12:00 | 18:00 | 10.8°C | 8.4°C | 0.34 | 3 | ENE | 87 | 1026 |
| 13:00 | 19:00 | 10.7°C | 8.3°C | 0.77 | 2.6 | ENE | 82 | 1026 |
| 14:00 | 20:00 | 11.6°C | 9.2°C | 0.7 | 2.8 | ENE | 80 | 1026 |
| 15:00 | 21:00 | 11.5°C | 9.1°C | 0.5 | 2.7 | ENE | 77 | 1026 |
| 16:00 | 22:00 | 11.4°C | 9.5°C | 0.5 | 2 | ESE | 80 | 1025 |
| 17:00 | 23:00 | 11.4°C | 9.5°C | 0.37 | 2.1 | E | 81 | 1025 |
| 18:00 | 00:00 | 10.4°C | 8.5°C | 0.24 | 1.8 | ESE | 82 | 1025 |
| 19:00 | 01:00 | 10.1°C | 8.2°C | 0.06 | 1.8 | SE | 82 | 1026 |
| 20:00 | 02:00 | 9.3°C | 7.8°C | 0.05 | 1.3 | SE | 88 | 1026 |
| 21:00 | 03:00 | 8.4°C | 7°C | 0.01 | 1 | S | 92 | 1025 |
| 22:00 | 04:00 | 8.5°C | 7°C | 0.01 | 1.3 | SW | 92 | 1026 |
| 23:00 | 05:00 | 8.5°C | 7.4°C | 0.02 | 0.7 | W | 92 | 1025 |
Nearby cities
Need this verified for an official or legal purpose? Request a weather verification report.
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 19 May 2023 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.