Home / Altadena / 24 December 2017
Altadena
United States · 24 December 2017
← 23 December 201725 December 2017 →
Average
13.3°C
low 7.6°C · high 21.5°C
Rainfall
0mm
dry day
Wind
1.8m/s
daily average
Humidity
20.3%
daily average
Cloud
77%
cover
Pressure
1020hPa
daily average
The temperature ranged from 7.6°C around 01:00 to 21.5°C around 13:00. 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
89th percentile
Low temperature
56th percentile
Rainfall
62th percentile
Wind
44th 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 13.3°C on this specific day.
Sun & daylight
Sunrise
06:56
Sunset
16:48
Day length
9h 52m
Hour by hour
Temperature (line) and hourly rainfall (bars), local time — America/Los_Angeles.
Cumulative rainfall through the day.
| Local time | UTC | Temp | Feels | Rain mm | Wind m/s | Dir | Humidity % | Pressure hPa |
|---|---|---|---|---|---|---|---|---|
| 00:00 | 08:00 | 8°C | 2.9°C | 0 | 2.7 | NNE | 23 | 1021 |
| 01:00 | 09:00 | 7.6°C | 2.6°C | 0 | 2.7 | NNE | 27 | 1021 |
| 02:00 | 10:00 | 9°C | 3.7°C | 0 | 3 | NNE | 22 | 1021 |
| 03:00 | 11:00 | 8.8°C | 3.6°C | 0 | 3 | NNE | 23 | 1021 |
| 04:00 | 12:00 | 8.1°C | 2.9°C | 0 | 3 | NNE | 26 | 1021 |
| 05:00 | 13:00 | 8.1°C | 2.9°C | 0 | 3.1 | NNE | 25 | 1020 |
| 06:00 | 14:00 | 8.3°C | 3°C | 0 | 3.1 | NNE | 24 | 1020 |
| 07:00 | 15:00 | 8.3°C | 2.9°C | 0 | 3.1 | NNE | 20 | 1021 |
| 08:00 | 16:00 | 10.4°C | 5°C | 0 | 3.3 | NNE | 20 | 1021 |
| 09:00 | 17:00 | 13.7°C | 8.5°C | 0 | 2.9 | NNE | 18 | 1021 |
| 10:00 | 18:00 | 16.7°C | 12.1°C | 0 | 2 | NNE | 13 | 1021 |
| 11:00 | 19:00 | 18.5°C | 14.2°C | 0 | 1.3 | NE | 9 | 1021 |
| 12:00 | 20:00 | 20.3°C | 16.5°C | 0 | 0.5 | NE | 7 | 1020 |
| 13:00 | 21:00 | 21.5°C | 17.8°C | 0 | 0.2 | SW | 4 | 1019 |
| 14:00 | 22:00 | 21.3°C | 17.7°C | 0 | 0.7 | SSW | 12 | 1018 |
| 15:00 | 23:00 | 21.3°C | 17.5°C | 0 | 1.2 | SSW | 13 | 1018 |
| 16:00 | 00:00 | 19.7°C | 16.1°C | 0 | 1 | SSW | 15 | 1018 |
| 17:00 | 01:00 | 16.4°C | 13.1°C | 0 | 1.1 | SSW | 24 | 1018 |
| 18:00 | 02:00 | 16.7°C | 13.7°C | 0 | 0.2 | SSE | 18 | 1018 |
| 19:00 | 03:00 | 13.2°C | 10°C | 0 | 1 | ENE | 30 | 1018 |
| 20:00 | 04:00 | 11.7°C | 8.1°C | 0 | 1.6 | ENE | 32 | 1018 |
| 21:00 | 05:00 | 11.4°C | 7.7°C | 0 | 1.4 | NE | 30 | 1019 |
| 22:00 | 06:00 | 11.1°C | 7.5°C | 0 | 1.1 | NE | 28 | 1019 |
| 23:00 | 07:00 | 10.2°C | 6.6°C | 0 | 1 | NE | 25 | 1020 |
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
- Altadena — 34.250°, -118.250°, ERA5 grid cell center, 12.8 km from requested point
- Time zone
- America/Los_Angeles
- What's shown here
- The hourly and daily record for 24 December 2017 specifically — not a monthly average. See the Altadena 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 Altadena, United States (34.25°N, 118.25°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Altadena, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 21, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Altadena, 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 Altadena, 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.