August 2024 was fairly cool with a few thunderstorms that brought at least one record rainfall to Chilliwack, making it the wettest August overall since 2008.
Until about mid month, a strong ridge of high pressure produced dry and sunny conditions across the southern region, according to Roger Pannett, Chilliwack's weather watcher, from his August 2024 weather report.
There were eight sweltering-hot days with temperatures over 30 C in August, whereas the average is two such hot days.
Temperatures hit their peak on Aug. 1 and Aug. 9 at 32.5 C, which is not surprising since the date of Aug. 9, with an average 26 C, "is statistically the warmest day of the year," Pannett said.
The minimum temperature observed was 9.2 C, overnight on August 28 - the coolest August temperature in 12 years.
No high temperature records were broken but after the mid month point, unstable and turbulent conditions arrived with thunderstorm activity, above normal, on three days delivering the stormiest August in 14 years. The early-morning and nocturnal thunderstorms on Aug. 18, were unusual.
On Aug. 23 a low pressure system from Oregon moved across southern B.C. with thunderstorms, hail and heavy showers.
The record 41.2 mm rainfall exceeded the previous record rainfall for the date of 22.4 mm in 1968.
On Aug. 24 beneath cloudy skies with morning showers , a record low 14.9 C (8.5°C below normal ) became the high for that day.
"It was the coolest Chilliwack August day temperature in 64 years," Pannett noted.
Previous record low maximum for the date was 16.7 C in 1927.
After the passage of a Pacific cold front, with its associated gusty winds and rain, from Aug. 27 to month's end a building ridge of high pressure resulted in mostly clear and sunny skies with a return to above normal and increasing temperatures.
With rainfall 144.13 per cent above normal it was the wettest August since the record 218.7 mm in 2008. Total precipitation in August was 93.4mm, compared to the 30-year average of 64.8 mm. That made Chilliwack's total precipitation for the year 850.2 mm on 113 days in 2024, compared to the 30-year average of 1,047.8 mm on 106 days.
With mean temperatures 2.45 C above normal, (based on 1951-80 average), it was the 24th consecutive August with above average mean temperatures, including the 13th consecutive year with mean temperatures in excess of the + (or -)1.2°C standard deviation.
Since 2012, August mean temperatures have been 1.88 C to 4.75 C above normal, a warming trend never previously observed in the past 129 years. High UV levels were reported on 24 days, peaking at UV 8 readings.
