Boulder
United States · 20 May 2019
Average
1.6°C
low -1.1°C · high 3.8°C
Rainfall
19.8mm
rain recorded
Wind
1.7m/s
daily average
Humidity
94.2%
daily average
Cloud
99%
cover
Pressure
1012hPa
daily average
The temperature ranged from -1.1°C around 23:00 to 3.8°C around 01:00. Rain was recorded across 24 hours, from around 00:00 to 23:00 (19.8mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
2th percentile
Low temperature
6th percentile
Rainfall
97th percentile
Wind
26th 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 11.3°C, versus 1.6°C on this specific day.
Sun & daylight
Sunrise
05:41
Sunset
20:13
Day length
14h 32m
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 | 3.7°C | 1.6°C | 0.47 | 0.8 | N | 91 | 1015 |
| 01:00 | 07:00 | 3.8°C | 1.7°C | 0.77 | 0.6 | N | 90 | 1015 |
| 02:00 | 08:00 | 3°C | 0.9°C | 0.69 | 0.5 | N | 93 | 1014 |
| 03:00 | 09:00 | 2.3°C | -0.1°C | 0.58 | 0.8 | N | 91 | 1014 |
| 04:00 | 10:00 | 1.2°C | -1.6°C | 0.64 | 1.2 | N | 94 | 1015 |
| 05:00 | 11:00 | 0.9°C | -2.8°C | 0.67 | 2.6 | NE | 95 | 1014 |
| 06:00 | 12:00 | 0.9°C | -2.6°C | 0.47 | 2.2 | NE | 94 | 1015 |
| 07:00 | 13:00 | 0.7°C | -3.1°C | 0.34 | 2.7 | ENE | 96 | 1015 |
| 08:00 | 14:00 | 0.8°C | -2.2°C | 0.52 | 1.6 | ENE | 96 | 1016 |
| 09:00 | 15:00 | 1.6°C | -0.8°C | 0.66 | 0.8 | NNE | 94 | 1015 |
| 10:00 | 16:00 | 2.1°C | -0.9°C | 0.59 | 1.8 | ENE | 94 | 1013 |
| 11:00 | 17:00 | 1.5°C | -2.1°C | 0.8 | 2.5 | E | 97 | 1012 |
| 12:00 | 18:00 | 2°C | -1.6°C | 0.78 | 2.7 | E | 98 | 1012 |
| 13:00 | 19:00 | 2.3°C | -1.4°C | 0.54 | 2.7 | ENE | 94 | 1011 |
| 14:00 | 20:00 | 2.8°C | -0.6°C | 0.79 | 2.4 | ENE | 91 | 1010 |
| 15:00 | 21:00 | 3.1°C | -0.6°C | 0.8 | 2.8 | ENE | 89 | 1009 |
| 16:00 | 22:00 | 1.5°C | -1°C | 0.73 | 0.9 | NE | 92 | 1010 |
| 17:00 | 23:00 | 2.3°C | -1.1°C | 0.31 | 2.1 | NE | 88 | 1009 |
| 18:00 | 00:00 | 1.9°C | -1.7°C | 0.65 | 2.5 | ENE | 94 | 1010 |
| 19:00 | 01:00 | 1.4°C | -1.9°C | 0.96 | 1.9 | ENE | 96 | 1010 |
| 20:00 | 02:00 | 1°C | -2.3°C | 1.52 | 2 | ENE | 97 | 1011 |
| 21:00 | 03:00 | -0.5°C | -4°C | 1.68 | 2.1 | ENE | 100 | 1012 |
| 22:00 | 04:00 | -0.8°C | -3.6°C | 2.07 | 0.9 | NNW | 98 | 1011 |
| 23:00 | 05:00 | -1.1°C | -3.5°C | 1.81 | 0.4 | N | 98 | 1010 |
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 2019 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 (2026-07-19). 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 19, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Boulder, 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 Boulder, 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.