Home / Altadena / 26 December 2017
Altadena
United States · 26 December 2017
← 25 December 201727 December 2017 →
Average
12.5°C
low 6.5° · high 20.6°
Rainfall
0mm
dry day
Wind
1.3m/s
daily average
Humidity
38%
daily average
Cloud
53%
cover
Pressure
1019hPa
daily average
The temperature ranged from 6.5°C around 04:00 to 20.6°C around 15:00. 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
86th percentile
Low temperature
40th percentile
Rainfall
62th percentile
Wind
18th 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 12.5°C on this specific day.
Sun & daylight
Sunrise
06:57
Sunset
16:50
Day length
9h 53m
Hour by hour
Temperature (line) and hourly rainfall (bars), local time — America/Los_Angeles.
Cumulative rainfall through the day.
| Local time | UTC | Temp °C | Feels °C | Rain mm | Wind m/s | Dir | Humidity % | Pressure hPa |
|---|---|---|---|---|---|---|---|---|
| 00:00 | 08:00 | 10.3 | 7.3 | 0 | 1.2 | NNE | 43 | 1019 |
| 01:00 | 09:00 | 9.3 | 6 | 0 | 1.3 | NNE | 42 | 1018 |
| 02:00 | 10:00 | 7.7 | 4.2 | 0 | 1.8 | NNE | 51 | 1019 |
| 03:00 | 11:00 | 7.4 | 4 | 0 | 1.6 | NNE | 52 | 1019 |
| 04:00 | 12:00 | 6.5 | 2.9 | 0 | 1.7 | NNE | 50 | 1019 |
| 05:00 | 13:00 | 6.5 | 2.8 | 0 | 1.9 | NNE | 49 | 1019 |
| 06:00 | 14:00 | 6.5 | 2.7 | 0 | 2.2 | NNE | 53 | 1019 |
| 07:00 | 15:00 | 6.6 | 2.6 | 0 | 2.3 | NNE | 52 | 1019 |
| 08:00 | 16:00 | 8.4 | 4.3 | 0 | 2.5 | NNE | 45 | 1020 |
| 09:00 | 17:00 | 12.2 | 8.2 | 0 | 2 | NNE | 31 | 1020 |
| 10:00 | 18:00 | 15.3 | 12.1 | 0 | 1 | NNE | 26 | 1021 |
| 11:00 | 19:00 | 16.9 | 14.2 | 0 | 0.4 | N | 25 | 1020 |
| 12:00 | 20:00 | 17.8 | 15.2 | 0 | 0.2 | WNW | 24 | 1019 |
| 13:00 | 21:00 | 19.4 | 16.7 | 0 | 0.4 | W | 21 | 1018 |
| 14:00 | 22:00 | 20.5 | 18.1 | 0 | 0.5 | ESE | 25 | 1018 |
| 15:00 | 23:00 | 20.6 | 18.3 | 0 | 0.6 | SSE | 26 | 1018 |
| 16:00 | 00:00 | 20.1 | 17.6 | 0 | 0.6 | SSE | 25 | 1018 |
| 17:00 | 01:00 | 18.3 | 15.9 | 0 | 0.6 | S | 29 | 1019 |
| 18:00 | 02:00 | 16.4 | 14.2 | 0 | 0.6 | NNE | 34 | 1019 |
| 19:00 | 03:00 | 12.5 | 9.6 | 0 | 1.5 | NNE | 46 | 1020 |
| 20:00 | 04:00 | 11.8 | 8.8 | 0 | 1.5 | NNE | 44 | 1020 |
| 21:00 | 05:00 | 10.8 | 7.5 | 0 | 1.6 | NNE | 42 | 1020 |
| 22:00 | 06:00 | 9.6 | 5.9 | 0 | 1.9 | NNE | 40 | 1020 |
| 23:00 | 07:00 | 9.1 | 5.1 | 0 | 2 | NNE | 37 | 1021 |
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 26 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 (2026-07-17). 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 17, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Altadena, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 17, 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 2026-07-17},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.