Home / Altadena / 31 December 2016
Altadena
United States · 31 December 2016
← 30 December 20161 January 2017 →
Average
9.4°C
low 5.6°C · high 11.2°C
Rainfall
10.3mm
rain recorded
Wind
1.7m/s
daily average
Humidity
95.3%
daily average
Cloud
89%
cover
Pressure
1013hPa
daily average
The temperature ranged from 5.6°C around 23:00 to 11.2°C around 10:00. Rain was recorded across 20 hours, from around 00:00 to 20:00 (10.3mm total).
How unusual was this day?
Compared against the same 135 calendar days (±7 days) across the other 9 years on file.
High temperature
8th percentile
Low temperature
30th percentile
Rainfall
89th percentile
Wind
38th 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°C, versus 9.4°C on this specific day.
Sun & daylight
Sunrise
06:58
Sunset
16:53
Day length
9h 55m
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 | 10.7°C | 9.9°C | 0.65 | 1.3 | SSW | 97 | 1014 |
| 01:00 | 09:00 | 10.5°C | 9.8°C | 0.38 | 1.1 | SSW | 98 | 1014 |
| 02:00 | 10:00 | 10.6°C | 9.7°C | 0.32 | 1.6 | S | 99 | 1014 |
| 03:00 | 11:00 | 10.8°C | 9.8°C | 0.29 | 1.7 | S | 98 | 1014 |
| 04:00 | 12:00 | 10.8°C | 9.9°C | 0.29 | 1.6 | SSW | 99 | 1014 |
| 05:00 | 13:00 | 10.5°C | 9.6°C | 0.29 | 1.6 | SSW | 99 | 1014 |
| 06:00 | 14:00 | 10.1°C | 9.1°C | 0.15 | 1.4 | SSW | 99 | 1014 |
| 07:00 | 15:00 | 10.4°C | 9.6°C | 0.17 | 0.9 | S | 91 | 1014 |
| 08:00 | 16:00 | 10.7°C | 10.1°C | 0.09 | 0.7 | SSE | 93 | 1014 |
| 09:00 | 17:00 | 10.9°C | 9.6°C | 0.16 | 1.8 | S | 93 | 1014 |
| 10:00 | 18:00 | 11.2°C | 9.4°C | 0.35 | 2.4 | S | 90 | 1015 |
| 11:00 | 19:00 | 10.8°C | 8.9°C | 0.61 | 2.6 | SSW | 93 | 1014 |
| 12:00 | 20:00 | 10.7°C | 8.9°C | 0.55 | 2.4 | SSW | 90 | 1013 |
| 13:00 | 21:00 | 11.1°C | 9.5°C | 0.45 | 2.3 | SSW | 92 | 1012 |
| 14:00 | 22:00 | 9.7°C | 8°C | 0.89 | 2.1 | S | 95 | 1012 |
| 15:00 | 23:00 | 9.5°C | 7.4°C | 0.87 | 2.5 | S | 95 | 1012 |
| 16:00 | 00:00 | 9.1°C | 7°C | 1.16 | 2.4 | SSW | 96 | 1011 |
| 17:00 | 01:00 | 8.5°C | 6.1°C | 1.28 | 2.5 | SW | 95 | 1012 |
| 18:00 | 02:00 | 7.8°C | 6.1°C | 0.72 | 1.2 | W | 93 | 1012 |
| 19:00 | 03:00 | 6.7°C | 5.2°C | 0.41 | 0.9 | NE | 97 | 1012 |
| 20:00 | 04:00 | 6.6°C | 4.8°C | 0.11 | 1.3 | ENE | 97 | 1012 |
| 21:00 | 05:00 | 6.5°C | 4.7°C | 0.04 | 1.2 | NE | 96 | 1012 |
| 22:00 | 06:00 | 5.9°C | 3.9°C | 0.01 | 1.3 | NNE | 96 | 1012 |
| 23:00 | 07:00 | 5.6°C | 3.6°C | 0.02 | 1.3 | NNE | 96 | 1013 |
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
- 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 31 December 2016 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 (2026-07-19). 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 19, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Altadena, 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 Altadena, 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.