Weather on December 21
Allentown, PA
55 Years of Data
Avg High
40°F
Avg Low
24°F
Warmest
2018
58°F avg
Coldest
1989
14°F avg
About This Date
December 21st in Allentown, PA typically brings chilly winter weather, with average highs around 40°F and lows near 24°F. Over 55 years of records, the warmest December 21st was in 2018 (58°F average), while the coldest was 1989 (14°F) — a 44°F range across recorded history. Precipitation has occurred on 29% of recorded December 21st dates, with snow falling 7% of the time. The last decade has been 3.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.9°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in Allentown, PA? Bring layers as temperatures can vary throughout the day.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 45° | 23° | 34° | — | — |
| 2024 | 32° | 15° | 24° | 0.03" | 0.1" |
| 2023 | 45° | 27° | 36° | — | — |
| 2022 | 40° | 17° | 29° | — | — |
| 2021 | 40° | 17° | 29° | 0.1" | — |
| 2020 | 37° | 32° | 35° | — | — |
| 2019 | 34° | 18° | 26° | — | — |
| 2018warmest | 64° | 52° | 58° | 2.9" | — |
| 2017 | 41° | 25° | 33° | — | — |
| 2016 | 42° | 16° | 29° | — | — |
| 2015 | 50° | 27° | 39° | — | — |
| 2014 | 37° | 25° | 31° | — | — |
| 2013 | 50° | 33° | 42° | — | — |
| 2012 | 56° | 34° | 45° | 3.66" | — |
| 2011 | 55° | 38° | 46° | 0.79" | — |
| 2010 | 36° | 26° | 31° | — | — |
| 2009 | 35° | 18° | 26° | — | — |
| 2008 | 35° | 20° | 27° | 0.36" | 0.6" |
| 2007 | 36° | 28° | 32° | 0.03" | — |
| 2006 | 51° | 26° | 39° | — | — |
| 2005 | 31° | 15° | 23° | — | — |
| 2004 | 30° | 10° | 20° | — | — |
| 2003 | 36° | 18° | 27° | — | — |
| 2002 | 43° | 27° | 35° | — | — |
| 2001 | 43° | 29° | 36° | — | — |
| 2000 | 30° | 8° | 19° | — | — |
| 1999 | 42° | 33° | 38° | — | — |
| 1998 | 52° | 42° | 47° | — | — |
| 1997 | 38° | 20° | 29° | — | — |
| 1996 | 30° | 11° | 20° | — | — |
| 1995 | 28° | 6° | 17° | — | — |
| 1994 | 52° | 24° | 38° | — | — |
| 1993 | 43° | 35° | 39° | 2.64" | — |
| 1992 | 36° | 23° | 29° | — | — |
| 1991 | 45° | 31° | 38° | — | — |
| 1990 | 56° | 40° | 48° | 0.94" | — |
| 1989coldest | 20° | 8° | 14° | — | 0.2" |
| 1988 | 51° | 34° | 42° | 0.25" | — |
| 1987 | 45° | 33° | 39° | — | — |
| 1986 | 40° | 25° | 32° | — | — |
| 1985 | 29° | 12° | 20° | — | — |
| 1984 | 38° | 30° | 34° | 1.8" | — |
| 1983 | 26° | 6° | 16° | — | — |
| 1982 | 39° | 33° | 36° | — | — |
| 1981 | 27° | 9° | 18° | 0.03" | — |
| 1980 | 24° | 10° | 17° | — | — |
| 1979 | 32° | 13° | 22° | — | — |
| 1978 | 41° | 32° | 37° | 0.71" | — |
| 1977 | 45° | 32° | 38° | 2.97" | — |
| 1976 | 36° | 18° | 27° | — | — |
| 1975 | 30° | 22° | 26° | — | — |
| 1974 | 40° | 30° | 35° | — | — |
| 1973 | 54° | 22° | 38° | 3.25" | 1" |
| 1972 | 36° | 33° | 34° | 1.07" | — |
| 1971 | 51° | 35° | 43° | — | — |
55 years of data from ALLENTOWN LEHIGH VLY INTL AP