Chilliwack Weather Review December 2020 – A Touch Warmer With A Few Records

Chilliwack (Roger Pannett/Environment Canada) – During the first week of December an upper level ridge of high pressure produced welcome clear, sunny and mild conditions. For the remainder of the month an unrelenting storm track, aimed at B.C., resulted in predominantly mild, rainy weather.

Three record high temperatures occurred: –

Date New Record Previous Record

December 8^th. High Minimum 7.7 ⁰C (+7.7 ⁰C) 7.0 ⁰C in 2015.

December 19^th. High Mean 9.45 ⁰C (+6.75 ⁰C) 9.3 ⁰C in 2004.

December 19^th. High Maximum 13.4 ⁰C (+8.1 ⁰C) 11.9 ⁰C in 2004.

(Peak temperature for the month.)

With the arrival of the winter season on December 21^st, abundant moisture associated with a deepening Pacific low-pressure system, moving across Washington state, transitioned into heavy wet snow. Just in time for Christmas,

‘Let it snow! Let It snow! Let it snow!’ The 31.2 cm snowfall was the snowiest December day since the 31.8 cm snow fall on December 10^th, 2016.

The 13 cm of residual snow on the ground assured a White Christmas. (The most snow since the 33-37 cm on Christmas Day 2008.)

On December 23^rd, beneath clear overnight skies, temperatures fell to the low for the month at -2.3 ⁰C the first killing frost of the season.

Prior to months end, mild rainy conditions returned as another series of Pacific frontal systems moved onshore.

With mean temperatures 1.76 ⁰C above normal it was the 14^th consecutive month with above normal mean temperatures.

With total precipitation >21% below normal, including snowfall at > 10 % below normal, it was the 22^nd consecutive December with precipitation totals below average.

CITY OF CHILLIWACK WEATHER REPORT

December 2020

Data recorded by Roger Pannett, Volunteer Weather Observer for Environment Canada at Chilliwack, B.C.

Variable	December 2020	30 Year Average
Mean Maximum	7.59 C	6.2 C
Mean Minimum	2.53 C	0.4 C
Mean Temperature	5.06 C	3.3 C
Rainfall	200.7 mm	259.6 mm
Snowfall	31.2 cm	34.8 cm
Total Precipitation	231.9 mm	294.4 mm
Days of Rain	20 days	18 days
Days of Snow	1 day	5 days
Total Days of Precipitation	20 days	22 days
Frosts	6	13
Relative humidity average	81.84 %	.