Hillsboro, OR weather in December
Expect chilly weather with rain on most days in Hillsboro in December, with highs near 44°F and lows near 33°F. Rain or snow falls on about 21 days. Snowfall averages about 1.7 in. It is one of the coldest months in Hillsboro. Pack rain gear.
- Normal high
- 44°F
- Normal low
- 33°F
- Wet days
- 21
- 8.2 in total
- Snowfall
- 1.7 in
- normal snowfall
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 46°F | 43°F |
| Normal low | 34°F | 32°F |
| Chance of a wet day | 67% | 68% |
| Sunrise / sunset | 7:31 am / 4:30 pm | 7:52 am / 4:37 pm |
| Daylight | 9.0 h | 8.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical December day
- 6 am37°Fdew point 35°F
- 9 am38°Fdew point 36°F
- Noon43°Fdew point 37°F
- 3 pm44°Fdew point 38°F
- 6 pm41°Fdew point 37°F
- 9 pm39°Fdew point 36°F
NOAA hourly normals (local standard time) from Portland-Hillsboro Airport (2 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F0 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow21 of 31
- Notable rainat least 0.10 in14 of 31
- Freezing nightslow 32°F or below13 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain and snow in December
Normal precipitation is 8.2 in; a dry December brings about 4.9 in and a wet one about 10.5 in (25th and 75th percentiles). About 6 days bring half an inch or more, and about 2 an inch or more. Normal snowfall is 1.7 in, with about 1 day of an inch or more.
How December varies from year to year
- Warmest December, 1991-20201999: average high 50°F
- Coolest December2013: average high 39°F
- Wettest December2015: 18.8 in
- Driest December2013: 1.4 in
- Highest reading62°F (December 13, 2004)
- Lowest reading8°F (December 8, 2013)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
December compared with November and January
| November | December | January | |
|---|---|---|---|
| Normal high | 51°F | 44°F | 45°F |
| Normal low | 36°F | 33°F | 33°F |
| Wet days | 19 | 21 | 20 |
| Comfortable days | 1 | 0 | 0 |
| Daylight | 9.5 h | 8.8 h | 9.2 h |
Highs change by -7°F from November and +1°F into January.
Nearby alternatives in December
- Drier: Bend, OR130 mi · high 41°F · 9 wet days
- Cooler: Leavenworth, WA181 mi · high 34°F · 14 wet days
How Hillsboro ranks in December
- Normal high249th warmest of 378 cities; 5th of 6 in Oregon
- Wet days374th driest of 378
- Comfortable days323rd most of 340
What to pack for Hillsboro in December
- A warm jacket – lows near 33°F, highs near 44°F
- A rain jacket or umbrella – rain or snow on about 21 days
Heating and cooling
December has 825 heating degree days and 0 cooling degree days (base 65°F), 15% of the year's total heating and cooling demand.
Questions
How cold is Hillsboro in December?
The normal high is 44°F and the normal low is 33°F. From 1991 to 2020 the coldest December reading was 8°F (most recently on December 8, 2013).
Does it rain a lot in Hillsboro in December?
About 21 days in December have at least 0.01 in of precipitation, and the normal total is 8.2 in. The wettest December in 1991-2020 was in 2015 (18.8 in); the driest was in 2013 (1.4 in).
Does it snow in Hillsboro in December?
Yes. Normal snowfall in December is 1.7 in.
Is December a good time to visit Hillsboro?
December ranks 12th of 12 months on our comfort score for Hillsboro (29 out of 100). It has almost no comfortable days. The best month is June.
Where the numbers come from
- Temperature and snow depth: Forest Grove (USC00352997), 5.5 mi W of the city center, 180 ft . NOAA normals and daily records, 1991-2020.
- Rain and snowfall: Dilley 2 S (USC00352325), 7.3 mi SW of the city center, 194 ft . NOAA normals and daily records, 1991-2020.
- Frost dates and humidity and wind by hour: Portland-Hillsboro Airport (USW00094261), 2.3 mi ENE of the city center, 204 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Portland International Airport (726980-24229), 19 mi ENE of the city center, 22 ft (173 ft lower than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).