Weather on December 15
Hillsboro, OR
55 Years of Data
Avg High
46°F
Avg Low
35°F
Warmest
2025
55°F avg
Coldest
2008
23°F avg
About This Date
December 15th in Hillsboro, OR typically brings chilly winter weather, with average highs around 46°F and lows near 35°F. Over 55 years of records, the warmest December 15th was in 2025 (55°F average), while the coldest was 2008 (23°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 67% of December 15th dates historically, with the wettest December 15th recording 3.66" of rain. The last decade has been 2.0°F cooler on this date compared to 20-30 years ago.
The last decade has been 2.0°F cooler on this date compared to 20-30 years ago.
Planning for December 15th in Hillsboro, OR? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
Cooling Trend
0.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025warmest | 63° | 47° | 55° | 1.24" | — |
| 2024 | 46° | 36° | 41° | 0.41" | — |
| 2023 | 53° | 31° | 42° | — | — |
| 2022 | 48° | 23° | 36° | — | — |
| 2021 | 41° | 36° | 38° | 0.94" | — |
| 2020 | 49° | 41° | 45° | 0.28" | — |
| 2019 | 41° | 35° | 38° | — | — |
| 2018 | 47° | 33° | 40° | 0.2" | — |
| 2017 | 39° | 26° | 33° | 0.03" | — |
| 2016 | 32° | 21° | 27° | — | — |
| 2015 | 40° | 36° | 38° | 0.13" | — |
| 2014 | 50° | 43° | 46° | — | — |
| 2013 | 43° | 36° | 39° | 0.03" | — |
| 2012 | 39° | 30° | 35° | 0.86" | — |
| 2011 | 44° | 34° | 39° | 0.05" | — |
| 2010 | 46° | 38° | 42° | 0.18" | — |
| 2009 | 50° | 40° | 45° | 2.26" | — |
| 2008coldest | 26° | 20° | 23° | — | — |
| 2007 | 47° | 36° | 41° | 0.13" | — |
| 2006 | 45° | 29° | 37° | 0.74" | — |
| 2005 | 37° | 20° | 28° | — | — |
| 2004 | 49° | 35° | 42° | — | — |
| 2003 | 43° | 36° | 39° | 0.03" | — |
| 2002 | 59° | 45° | 52° | 1.57" | — |
| 2001 | 44° | 37° | 41° | 0.43" | — |
| 2000 | 45° | 39° | 42° | 0.23" | — |
| 1999 | 56° | 53° | 54° | 1.02" | — |
| 1998 | 47° | 34° | 40° | — | — |
| 1997 | 51° | 37° | 44° | 2.49" | — |
| 1996 | 36° | 30° | 33° | — | — |
| 1995 | 47° | 40° | 43° | — | — |
| 1994 | 48° | 41° | 45° | 0.64" | — |
| 1993 | 46° | 41° | 44° | 0.28" | — |
| 1992 | 49° | 31° | 40° | 0.3" | — |
| 1991 | 53° | 27° | 40° | — | — |
| 1990 | 45° | 29° | 37° | — | — |
| 1989 | 35° | 30° | 33° | 0.05" | — |
| 1988 | 47° | 27° | 37° | — | — |
| 1987 | 35° | 27° | 31° | 0.33" | — |
| 1986 | 51° | 31° | 41° | 0.08" | — |
| 1985 | 43° | 25° | 34° | — | — |
| 1984 | 46° | 30° | 38° | 0.25" | — |
| 1983 | 49° | 40° | 44° | 0.05" | — |
| 1982 | 49° | 42° | 45° | 2.31" | — |
| 1981 | 50° | 39° | 45° | 3.63" | — |
| 1980 | 47° | 33° | 40° | — | — |
| 1979 | 54° | 47° | 50° | — | — |
| 1978 | 41° | 28° | 35° | 0.08" | — |
| 1977 | 50° | 40° | 45° | 3.66" | — |
| 1976 | 56° | 39° | 47° | — | — |
| 1975 | 44° | 39° | 42° | 1.07" | — |
| 1974 | 54° | 43° | 48° | 0.48" | — |
| 1973 | 52° | 45° | 48° | 0.89" | — |
| 1972 | 33° | 20° | 26° | 0.08" | — |
| 1971 | 45° | 33° | 39° | 0.05" | — |
55 years of data from HILLSBORO