Home / Altadena / 25 December 2018
Altadena
United States · 25 December 2018
← 24 December 201826 December 2018 →
Average
11.3°C
low 8.6°C · high 15.9°C
Rainfall
3.6mm
rain recorded
Wind
2.2m/s
daily average
Humidity
67%
daily average
Cloud
28%
cover
Pressure
1010hPa
daily average
The temperature ranged from 8.6°C around 07:00 to 15.9°C around 13:00. Rain was recorded across 7 hours, from around 00:00 to 06:00 (3.6mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
42th percentile
Low temperature
70th percentile
Rainfall
79th percentile
Wind
61th 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 11.2°C, versus 11.3°C on this specific day.
Sun & daylight
Sunrise
06:56
Sunset
16:49
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 | 11.2°C | 10.2°C | 1.02 | 1.3 | SSE | 90 | 1011 |
| 01:00 | 09:00 | 10.7°C | 9.7°C | 0.94 | 1.2 | SSW | 90 | 1010 |
| 02:00 | 10:00 | 10.6°C | 10.1°C | 0.53 | 0.6 | NNW | 94 | 1011 |
| 03:00 | 11:00 | 10.3°C | 9.6°C | 0.18 | 0.7 | NNE | 91 | 1010 |
| 04:00 | 12:00 | 9.8°C | 9°C | 0.23 | 0.6 | NE | 91 | 1009 |
| 05:00 | 13:00 | 9.5°C | 8°C | 0.26 | 1.5 | NW | 91 | 1009 |
| 06:00 | 14:00 | 9.1°C | 7.8°C | 0.25 | 1.2 | NNE | 92 | 1009 |
| 07:00 | 15:00 | 8.6°C | 7°C | 0.08 | 1.2 | NE | 88 | 1009 |
| 08:00 | 16:00 | 9.5°C | 8°C | 0.04 | 1.3 | NNE | 87 | 1009 |
| 09:00 | 17:00 | 11.1°C | 9.8°C | 0.03 | 1 | N | 78 | 1009 |
| 10:00 | 18:00 | 12.2°C | 10°C | 0 | 2 | NNW | 68 | 1010 |
| 11:00 | 19:00 | 13.7°C | 10.6°C | 0.08 | 2.8 | NNW | 56 | 1009 |
| 12:00 | 20:00 | 14.7°C | 10.9°C | 0 | 3.7 | NNW | 51 | 1008 |
| 13:00 | 21:00 | 15.9°C | 11.5°C | 0 | 3.9 | NNW | 38 | 1007 |
| 14:00 | 22:00 | 15.1°C | 10.2°C | 0 | 4.4 | NNW | 38 | 1008 |
| 15:00 | 23:00 | 14.7°C | 9.9°C | 0 | 4.4 | NNW | 41 | 1008 |
| 16:00 | 00:00 | 13.7°C | 9.4°C | 0 | 3.6 | NNW | 43 | 1009 |
| 17:00 | 01:00 | 12.2°C | 8.3°C | 0 | 2.9 | NNW | 45 | 1009 |
| 18:00 | 02:00 | 11.2°C | 7.8°C | 0 | 2.1 | N | 49 | 1010 |
| 19:00 | 03:00 | 10°C | 6.9°C | 0 | 1.7 | N | 52 | 1011 |
| 20:00 | 04:00 | 9.4°C | 6.3°C | 0 | 1.9 | N | 56 | 1011 |
| 21:00 | 05:00 | 9.1°C | 5.6°C | 0 | 2.3 | N | 57 | 1012 |
| 22:00 | 06:00 | 9.5°C | 6°C | 0 | 2.7 | NNE | 60 | 1012 |
| 23:00 | 07:00 | 8.9°C | 5.1°C | 0 | 2.8 | NNE | 60 | 1013 |
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 25 December 2018 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.