No 30C+ Days In September – City Of Chilliwack September 2021 Weather Report

Chilliwack (Roger Pannett Environment Canada) – “Wake me up when September ends” – Green Day

For September 2021, no temperature records were observed. For the first time since September 2016, there were no hot days over 30.0°C.

Data recorded by Roger Pannett, Volunteer Weather Observer for Environment Canada at the City of Chilliwack.

Variable	September 2021	30 Year Average
Mean Maximum	20.62 C	21.0 C
Mean Minimum	12.0 C	10.2 C
Mean Temperature	16.31C	15.6 C
Rainfall	211.6 mm	112.7 mm
Snowfall	–	–
Total Precipitation	211.6 mm	112.7 mm
Days of Rain	16 days	11 days
Days of Snow	–	–
Total Days of Precipitation	16 days	11 days
Frosts	–	–
Relative humidity average	70.78 %

Throughout the month a series of Pacific frontal systems traversed the Province. With only a couple of weak transient high pressure ridges, sunny days were few and far between. Consequently, for the first time since September 2016,there were no hot days > 30.0°C. (The September average is 1 hot day with a + or – 1.6-day standard deviation.)

Temperature extremes for the month were the 28.9°C maximum (7.2°C above average) with a 31% relative humidity on September 9^th and a cool minimum of 5.4°C (3.8°C below average) on September 16^th.

No temperature records were observed.

For the 6^th consecutive September, mean temperatures were above normal at +0.71°C.

Rainfall was 187.75% above normal. The wettest September since the

221.7 mm rainfall in September 2010.

On September 17^th, a vigorous moisture laden Pacific frontal system, described as an,’Atmospheric river,’ produced an all time September record rainfall of 89.5 mm.(The previous record for the day was 30.2 mm in 1970 and the previous all time September record rainfall was 85.6 mm on September 23^rd, 1903. The City of Chilliwack rainfall records go back to 1879.)

September 17^th was the wettest Chilliwack day since the 100.3 mm rainfall on October 16^th, 2003.

The month concluded with more wet and windy conditions as an active jet stream remained in close proximity to southern B.C.

The City of Chilliwack 2021 precipitation total to date is 785.6 mm on 111 days compared to the 30-year average of 1,160.5 mm on 117 days.