Hamilton heat warning over; relief arrives after 130+ hours of humidity
Published August 9, 2022 at 11:02 am
Based on the dewpoint, Hamilton just had one of its longest August heatwaves of this century.
Some rain on Monday night, and the arrival of some September-y weather on Tuesday morning (Aug. 9) led to the public health unit lifting a heat warning that was in place for the previous three days. The milder temperatures, according to the seven-day forecast from Environment and Climate Change Canada (EC), are expected to last. The forecast highs over the next week range from 24C to 27C. The lows overnight — which might be more pertinent to downtown residents in the city’s urban heat islands — are pegged to be between 11 and 16C.
Monday saw a recorded high of 28.1 C at John C. Munro International Airport in south Hamilton, but the hourly low of 21.7 illustrated how a lack of cool air at night made it unpleasant for many of the city’s residents.
While it is unofficial, the city likely experienced a heatwave that lasted more than 130 hours. Hourly data from EC shows that the dewpoint was 19.8C at 11 p.m. on Monday. Dewpoint is a measure of the amount of moisture in the air and it increases as humidity (or the humidex) increases.
As of 6 p.m., per weather historian Rolf Campbell, the dewpoint had been 18C or higher for 128 consecutive hours. That made it at least the sixth-longest run of heat in the city since modern record-keeping began in 1970.
The record is 159 consecutive hours, set from July 28-Aug. 4, 2006. And while the record-keeping in Hamilton began more than a half-century ago, the 10 longest heatwaves have all come since 2000.
Videos
6pm today was #Hamilton's 128th consecutive hour with dewpoint ≥18°C which puts this run in 6th place for the longest run on record. If this continues, we will reach 5th place tomorrow at midnight. #YHM #YhmWx #ONWx pic.twitter.com/rrzCmLmClr
— Hamilton Weather Records🌤 (@YHM_Weather) August 9, 2022
Earlier this year, the Intact Centre on Climate Adaptation, in partnership with the University of Waterloo, released a study showing that Hamilton is one of the most vulnerable cities in Canada to extreme heat stimulated by climate change. Only Windsor, Ont., is more vulnerable.
The elected leadership in Hamilton declared a climate emergency in 2019, and voted 12-1 on Monday in favour of a climate adaptation strategy that will include creating a climate change office. The plan needs formal ratification at the next city council meeting, but it has already been supported by a majority of the elected representatives.
insauga's Editorial Standards and Policies advertising