December is one of the cooler months of the year in Altoona, with average highs near 3.1°C and lows around -4.8°C (mean -0.8°C). It is about average for rainfall, averaging 76 mm of rainfall and 86% relative humidity across the period.
December is one of the cooler months of the year in Altoona. Across 45 years of records, the warmest December in Altoona was 2015 — when the month averaged 5.9°C — while the coldest was 1989 at -7.1°C. Typical December days reach 3.1°C with nights near -4.8°C. The long-term trend is warming, about 0.4°C per decade.
December is about average for rainfall in Altoona, averaging 76 mm of rainfall. The wettest December on record was 1990 with 160 mm, while the driest was 1998 at 28 mm.
Relative humidity in Altoona during December averages 86%. The most humid December was 2005 at 92%, and the least humid was 1998 at 73%.
December receives about 1.4 kWh/m²/day of solar energy in Altoona. The sunniest Decembers were 2000 and 2006 at 1.7 kWh/m²/day, and the cloudiest was 2007 at 1.1.
Average wind speed in Altoona during December is 0.3 m/s. The windiest Decembers were 2022, 2024 and 2025, among others at 0.3 m/s, while the calmest were 1996, 2021 and 2023, among others at 0.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -2.0°C | -0.4°C | -1.7°C | -0.1°C | -0.1°C | +1.9°C |
| Avg High | 1.9°C | 3.7°C | 2.3°C | 3.6°C | 4.2°C | +2.3°C |
| Avg Low | -5.9°C | -4.4°C | -5.7°C | -3.8°C | -4.4°C | +1.5°C |
| Avg Rain | 62 mm | 75 mm | 80 mm | 83 mm | 80 mm | +18 mm |
December temperatures in Altoona have risen by about 1.6°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -24.6°C (1983) to a record high of 22.2°C (2001).
Rainfall in December is about average for rainfall, averaging 76 mm, with a wettest year of 160 mm.
A quieter season to visit Altoona
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Altoona. That said, December — with days averaging 3.1°C and nights around -4.8°C (mean -0.8°C) and moderate rainfall (76 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 1.8°C | -2.5°C | -6.7°C | 8.0°C | -13.8°C | 51 mm | 82% | 0.3 m/s | — |
| 2024 | 3.3°C | -0.7°C | -4.7°C | 13.5°C | -13.2°C | 73 mm | 85% | 0.3 m/s | 1.4 |
| 2023 | 6.8°C | 2.6°C | -1.6°C | 12.3°C | -6.1°C | 105 mm | 89% | 0.2 m/s | 1.3 |
| 2022 | 1.9°C | -2.4°C | -6.8°C | 12.9°C | -20.3°C | 97 mm | 91% | 0.3 m/s | 1.4 |
| 2021 | 8.0°C | 3.1°C | -1.8°C | 17.0°C | -7.5°C | 59 mm | 84% | 0.2 m/s | 1.6 |
| 2020 | 3.3°C | -0.7°C | -4.7°C | 13.4°C | -13.2°C | 98 mm | 87% | 0.3 m/s | 1.2 |
| 2019 | 3.7°C | -0.1°C | -3.9°C | 13.7°C | -13.9°C | 83 mm | 88% | 0.3 m/s | 1.4 |
| 2018 | 3.7°C | 0.2°C | -3.2°C | 13.8°C | -8.8°C | 140 mm | 92% | 0.3 m/s | 1.3 |
| 2017 | 1.2°C | -2.3°C | -5.7°C | 10.1°C | -14.3°C | 29 mm | 81% | 0.3 m/s | 1.5 |
| 2016 | 2.4°C | -1.4°C | -5.2°C | 9.0°C | -15.5°C | 66 mm | 83% | 0.3 m/s | 1.3 |
| 2015 🔥 | 10.2°C | 5.9°C | 1.6°C | 19.9°C | -5.3°C | 94 mm | 89% | 0.3 m/s | 1.2 |
| 2014 | 3.5°C | 0.1°C | -3.3°C | 12.7°C | -7.6°C | 61 mm | 86% | 0.3 m/s | 1.2 |
| 2013 | 1.9°C | -1.7°C | -5.4°C | 17.3°C | -11.6°C | 87 mm | 89% | 0.3 m/s | 1.2 |
| 2012 | 5.2°C | 1.5°C | -2.3°C | 18.9°C | -9.1°C | 114 mm | 92% | 0.3 m/s | 1.3 |
| 2011 | 5.1°C | 1.0°C | -3.1°C | 14.7°C | -9.4°C | 91 mm | 91% | 0.3 m/s | 1.4 |
| 2010 | -0.7°C | -4.0°C | -7.3°C | 13.0°C | -12.3°C | 69 mm | 85% | 0.3 m/s | 1.4 |
| 2009 | 0.8°C | -3.0°C | -6.9°C | 10.4°C | -15.3°C | 118 mm | 89% | 0.3 m/s | 1.4 |
| 2008 | 1.0°C | -2.8°C | -6.6°C | 9.4°C | -15.7°C | 141 mm | 88% | 0.3 m/s | 1.4 |
| 2007 | 2.8°C | -1.1°C | -5.0°C | 14.4°C | -16.3°C | 109 mm | 90% | 0.3 m/s | 1.1 |
| 2006 | 7.2°C | 2.4°C | -2.3°C | 20.6°C | -8.3°C | 49 mm | 85% | 0.3 m/s | 1.7 |
| 2005 | -0.6°C | -4.3°C | -8.0°C | 5.5°C | -14.7°C | 53 mm | 92% | 0.3 m/s | 1.4 |
| 2004 | 3.5°C | -0.8°C | -5.0°C | 11.5°C | -15.7°C | 70 mm | 86% | 0.3 m/s | 1.4 |
| 2003 | 2.1°C | -1.5°C | -5.1°C | 9.6°C | -10.5°C | 91 mm | 88% | 0.3 m/s | 1.4 |
| 2002 | 0.9°C | -2.9°C | -6.6°C | 8.7°C | -12.7°C | 73 mm | 87% | 0.3 m/s | 1.4 |
| 2001 | 6.5°C | 2.3°C | -1.9°C | 22.2°C | -9.9°C | 49 mm | 80% | 0.3 m/s | 1.5 |
| 2000 | -1.3°C | -5.4°C | -9.4°C | 5.9°C | -17.2°C | 47 mm | 82% | 0.3 m/s | 1.7 |
| 1999 | 4.2°C | 0.1°C | -4.0°C | 16.4°C | -11.5°C | 50 mm | 82% | 0.3 m/s | 1.4 |
| 1998 | 7.9°C | 2.8°C | -2.3°C | 21.9°C | -12.3°C | 28 mm | 73% | 0.3 m/s | 1.5 |
| 1997 | 2.9°C | -0.6°C | -4.1°C | 8.9°C | -9.9°C | 40 mm | 89% | 0.3 m/s | 1.5 |
| 1996 | 4.0°C | 0.3°C | -3.4°C | 14.6°C | -13.4°C | 104 mm | 92% | 0.2 m/s | 1.2 |
| 1995 | -0.8°C | -4.2°C | -7.7°C | 9.7°C | -14.2°C | 52 mm | 87% | 0.3 m/s | 1.6 |
| 1994 | 5.8°C | 1.3°C | -3.3°C | 16.0°C | -9.8°C | 69 mm | 86% | 0.3 m/s | 1.4 |
| 1993 | 1.9°C | -1.9°C | -5.7°C | 8.3°C | -14.3°C | 65 mm | 87% | 0.3 m/s | 1.3 |
| 1992 | 1.7°C | -1.9°C | -5.4°C | 15.0°C | -11.7°C | 109 mm | 90% | 0.3 m/s | 1.4 |
| 1991 | 4.2°C | 0.1°C | -4.0°C | 12.9°C | -12.9°C | 77 mm | 83% | 0.3 m/s | 1.4 |
| 1990 🌧️ | 4.7°C | 0.4°C | -3.9°C | 15.1°C | -11.7°C | 160 mm | 88% | 0.3 m/s | 1.4 |
| 1989 ❄️ | -3.3°C | -7.1°C | -11.0°C | 5.5°C | -17.4°C | 38 mm | 84% | 0.3 m/s | 1.6 |
| 1988 | 2.0°C | -2.0°C | -6.1°C | 9.2°C | -14.3°C | 40 mm | 79% | 0.3 m/s | 1.5 |
| 1987 | 3.6°C | -0.2°C | -4.0°C | 10.9°C | -11.8°C | 58 mm | 87% | 0.3 m/s | 1.3 |
| 1986 | 2.9°C | -0.9°C | -4.7°C | 11.9°C | -11.9°C | 79 mm | 88% | 0.3 m/s | 1.4 |
| 1985 | 0.4°C | -3.7°C | -7.9°C | 8.8°C | -16.1°C | 46 mm | 87% | 0.3 m/s | 1.3 |
| 1984 | 5.7°C | 1.6°C | -2.5°C | 18.5°C | -11.7°C | 77 mm | 89% | 0.3 m/s | 1.3 |
| 1983 | -1.3°C | -5.0°C | -8.6°C | 9.7°C | -24.6°C | 119 mm | 89% | 0.3 m/s | — |
| 1982 | 6.4°C | 2.0°C | -2.3°C | 19.2°C | -10.0°C | 49 mm | 85% | 0.2 m/s | — |
| 1981 | 0.6°C | -2.9°C | -6.4°C | 6.8°C | -14.2°C | 53 mm | 86% | 0.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 3.1°C with lows near -4.8°C (mean -0.8°C), based on 45 years of NASA POWER data.
December averages 76 mm of rainfall in Altoona, about average for rainfall. The wettest on record was 160 mm in 1990.
The hottest December reached 22.2°C in 2001. The coldest dipped to -24.6°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.6°C. Daytime highs moved from 2.4°C to 4.4°C and overnight lows from -5.5°C to -4.3°C over the same span.
December is one of the cooler months of the year in Altoona and about average for rainfall, so plan for around 3.1°C daytime highs and -4.8°C at night.
Not quite — December is the 3rd coolest month in Altoona, averaging -0.8°C.
For December in Altoona, pack warm layers and a jacket for chilly mornings, with typical highs of 3.1°C and lows of -4.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 86% — quite humid.
Average wind speed in December is 0.3 m/s. The windiest December on record averaged 0.3 m/s (1981).
The wettest December on record was 1990 with 160 mm. On average, December sees 76 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Altoona behaves each December, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for December specifically, along with year-by-year records and how the month has changed over the decades.
