December is one of the cooler months of the year in Pittsburgh, with average highs near 3.7°C and lows around -4.1°C (mean -0.2°C). It is about average for rainfall, averaging 75 mm of rainfall and 86% relative humidity across the period.
December is one of the cooler months of the year in Pittsburgh. Across 45 years of records, the warmest December in Pittsburgh was 2015 — when the month averaged 6.3°C — while the coldest was 1989 at -7.2°C. Typical December days reach 3.7°C with nights near -4.1°C. The long-term trend is warming, about 0.5°C per decade.
December is about average for rainfall in Pittsburgh, averaging 75 mm of rainfall. The wettest December on record was 1990 with 183 mm, while the driest was 2005 at 36 mm.
Relative humidity in Pittsburgh during December averages 86%. The most humid Decembers were 2010 and 2012 at 91%, and the least humid was 1988 at 78%.
December receives about 1.3 kWh/m²/day of solar energy in Pittsburgh. The sunniest December was 2000 at 1.7 kWh/m²/day, and the cloudiest were 2007 and 2020 at 1.1.
Average wind speed in Pittsburgh during December is 0.4 m/s. The windiest Decembers were 2023, 2024 and 2025, among others at 0.4 m/s, while the calmest were 2014, 2018 and 2021, among others at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -1.5°C | 0.1°C | -0.8°C | 0.5°C | 1.1°C | +2.6°C |
| Avg High | 2.2°C | 4.1°C | 3.2°C | 4.3°C | 5.3°C | +3.1°C |
| Avg Low | -5.3°C | -3.9°C | -4.8°C | -3.3°C | -3.0°C | +2.3°C |
| Avg Rain | 71 mm | 76 mm | 74 mm | 83 mm | 67 mm | -4 mm |
December temperatures in Pittsburgh have risen by about 2.3°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -23.1°C (1983) to a record high of 20.8°C (1998).
Rainfall in December is about average for rainfall, averaging 75 mm, with a wettest year of 183 mm.
A quieter season to visit Pittsburgh
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Pittsburgh. That said, December — with days averaging 3.7°C and nights around -4.1°C (mean -0.2°C) and moderate rainfall (75 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 | 2.8°C | -1.6°C | -6.0°C | 14.9°C | -12.7°C | 65 mm | 84% | 0.4 m/s | — |
| 2024 | 4.9°C | 1.0°C | -2.9°C | 16.1°C | -10.6°C | 72 mm | 83% | 0.4 m/s | 1.4 |
| 2023 | 8.0°C | 3.8°C | -0.3°C | 15.6°C | -6.0°C | 71 mm | 86% | 0.4 m/s | 1.3 |
| 2022 | 3.9°C | -0.3°C | -4.4°C | 16.3°C | -19.2°C | 50 mm | 86% | 0.4 m/s | 1.4 |
| 2021 | 8.6°C | 3.9°C | -0.8°C | 17.2°C | -6.1°C | 81 mm | 82% | 0.3 m/s | 1.4 |
| 2020 | 3.5°C | 0.0°C | -3.5°C | 15.3°C | -9.4°C | 65 mm | 87% | 0.4 m/s | 1.1 |
| 2019 | 5.6°C | 1.4°C | -2.8°C | 13.5°C | -12.1°C | 70 mm | 87% | 0.4 m/s | 1.3 |
| 2018 | 4.5°C | 0.8°C | -2.9°C | 15.3°C | -9.2°C | 111 mm | 90% | 0.3 m/s | 1.3 |
| 2017 | 1.8°C | -1.8°C | -5.3°C | 12.7°C | -13.6°C | 37 mm | 80% | 0.4 m/s | 1.5 |
| 2016 | 2.3°C | -1.5°C | -5.3°C | 13.5°C | -16.5°C | 91 mm | 85% | 0.4 m/s | 1.2 |
| 2015 🔥 | 10.7°C | 6.3°C | 1.9°C | 19.7°C | -5.6°C | 87 mm | 88% | 0.4 m/s | 1.2 |
| 2014 | 5.0°C | 1.2°C | -2.6°C | 13.5°C | -7.7°C | 67 mm | 84% | 0.3 m/s | 1.2 |
| 2013 | 2.9°C | -0.8°C | -4.6°C | 17.5°C | -12.3°C | 89 mm | 87% | 0.4 m/s | 1.2 |
| 2012 | 6.4°C | 2.4°C | -1.6°C | 18.0°C | -8.4°C | 149 mm | 91% | 0.4 m/s | 1.2 |
| 2011 | 5.7°C | 1.9°C | -1.9°C | 14.5°C | -7.2°C | 81 mm | 89% | 0.4 m/s | 1.4 |
| 2010 | -1.5°C | -4.5°C | -7.6°C | 8.6°C | -10.6°C | 50 mm | 91% | 0.4 m/s | 1.2 |
| 2009 | 1.9°C | -1.8°C | -5.5°C | 10.7°C | -11.5°C | 94 mm | 85% | 0.4 m/s | 1.4 |
| 2008 | 3.1°C | -1.2°C | -5.4°C | 16.1°C | -15.7°C | 135 mm | 83% | 0.4 m/s | 1.3 |
| 2007 | 3.9°C | 0.0°C | -4.0°C | 13.8°C | -10.1°C | 127 mm | 90% | 0.4 m/s | 1.1 |
| 2006 | 7.6°C | 2.8°C | -2.0°C | 20.0°C | -9.1°C | 38 mm | 82% | 0.4 m/s | 1.6 |
| 2005 | 0.6°C | -3.1°C | -6.7°C | 9.4°C | -16.6°C | 36 mm | 88% | 0.4 m/s | 1.4 |
| 2004 | 4.1°C | 0.0°C | -4.2°C | 17.0°C | -14.0°C | 64 mm | 86% | 0.4 m/s | 1.3 |
| 2003 | 2.8°C | -0.6°C | -4.1°C | 11.0°C | -10.2°C | 67 mm | 86% | 0.4 m/s | 1.4 |
| 2002 | 1.7°C | -1.8°C | -5.4°C | 10.2°C | -11.4°C | 60 mm | 86% | 0.4 m/s | 1.3 |
| 2001 | 6.9°C | 2.7°C | -1.4°C | 19.9°C | -9.8°C | 64 mm | 82% | 0.4 m/s | 1.4 |
| 2000 | -1.1°C | -5.0°C | -8.9°C | 6.1°C | -16.3°C | 55 mm | 81% | 0.4 m/s | 1.7 |
| 1999 | 4.7°C | 0.6°C | -3.5°C | 16.8°C | -11.6°C | 56 mm | 82% | 0.4 m/s | 1.4 |
| 1998 | 6.9°C | 2.1°C | -2.7°C | 20.8°C | -13.4°C | 49 mm | 79% | 0.4 m/s | 1.4 |
| 1997 | 3.4°C | 0.0°C | -3.4°C | 9.3°C | -11.7°C | 41 mm | 88% | 0.4 m/s | 1.4 |
| 1996 | 4.9°C | 1.0°C | -2.9°C | 13.4°C | -13.3°C | 71 mm | 90% | 0.4 m/s | 1.2 |
| 1995 | -0.2°C | -3.8°C | -7.5°C | 10.2°C | -17.2°C | 51 mm | 86% | 0.4 m/s | 1.5 |
| 1994 | 6.6°C | 2.1°C | -2.4°C | 15.1°C | -7.6°C | 66 mm | 86% | 0.3 m/s | 1.4 |
| 1993 | 2.4°C | -1.1°C | -4.7°C | 9.8°C | -13.2°C | 48 mm | 86% | 0.4 m/s | 1.3 |
| 1992 | 2.0°C | -1.4°C | -4.8°C | 12.6°C | -11.0°C | 85 mm | 90% | 0.4 m/s | 1.4 |
| 1991 | 4.4°C | 0.3°C | -3.7°C | 15.9°C | -13.1°C | 107 mm | 84% | 0.4 m/s | 1.4 |
| 1990 🌧️ | 5.7°C | 1.1°C | -3.5°C | 15.6°C | -12.6°C | 183 mm | 87% | 0.4 m/s | 1.3 |
| 1989 ❄️ | -3.5°C | -7.2°C | -11.0°C | 4.8°C | -20.9°C | 58 mm | 87% | 0.4 m/s | 1.5 |
| 1988 | 2.7°C | -1.3°C | -5.3°C | 13.4°C | -11.2°C | 51 mm | 78% | 0.4 m/s | 1.4 |
| 1987 | 4.1°C | 0.3°C | -3.5°C | 12.7°C | -10.1°C | 68 mm | 87% | 0.4 m/s | 1.2 |
| 1986 | 2.7°C | -0.7°C | -4.2°C | 12.1°C | -10.8°C | 86 mm | 88% | 0.3 m/s | 1.4 |
| 1985 | 0.1°C | -3.6°C | -7.3°C | 12.0°C | -16.7°C | 56 mm | 88% | 0.4 m/s | 1.3 |
| 1984 | 6.6°C | 2.5°C | -1.7°C | 18.6°C | -10.1°C | 83 mm | 88% | 0.4 m/s | 1.2 |
| 1983 | -1.3°C | -4.9°C | -8.4°C | 11.0°C | -23.1°C | 105 mm | 88% | 0.4 m/s | — |
| 1982 | 7.3°C | 3.3°C | -0.8°C | 20.1°C | -9.1°C | 66 mm | 87% | 0.4 m/s | — |
| 1981 | 1.1°C | -2.0°C | -5.2°C | 5.9°C | -13.2°C | 67 mm | 87% | 0.4 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 3.7°C with lows near -4.1°C (mean -0.2°C), based on 45 years of NASA POWER data.
December averages 75 mm of rainfall in Pittsburgh, about average for rainfall. The wettest on record was 183 mm in 1990.
The hottest December reached 20.8°C in 1998. The coldest dipped to -23.1°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 2.3°C. Daytime highs moved from 2.8°C to 5.6°C and overnight lows from -4.7°C to -2.9°C over the same span.
December is one of the cooler months of the year in Pittsburgh and about average for rainfall, so plan for around 3.7°C daytime highs and -4.1°C at night.
Not quite — December is the 3rd coolest month in Pittsburgh, averaging -0.2°C.
For December in Pittsburgh, pack warm layers and a jacket for chilly mornings, with typical highs of 3.7°C and lows of -4.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 86% — quite humid.
Average wind speed in December is 0.4 m/s. The windiest December on record averaged 0.4 m/s (1981).
The wettest December on record was 1990 with 183 mm. On average, December sees 75 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 Pittsburgh 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.
