Even though there’s still a month left in spring, bright sunshine, warm temperatures and humidex values approaching 30 are bathing London and Middlesex County in very summer-like weather today. While today’s expected high of 29º Celsius isn’t enough to trigger a Heat Alert, the Middlesex-London Health Unit is reminding the community that it’s important to consider the heat when planning outdoor activities when the mercury climbs.
Part of the Health Unit’s role is to issue weather advisories when certain conditions are met, so that local residents, schools, daycares and businesses can plan their outdoor work and activities appropriately. Depending on the expected daytime high temperatures and the number of days that those temperatures are expected to last, specific extreme temperature alerts will be issued based on the criteria below.
Heat Alerts
Heat Alerts are issued when one or more of the following criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher for one day, or;
- Environment Canada issues a forecast calling for a Humidex value of 40 or higher for one day.
Heat Warnings
Heat Warnings are issued when one or more of the following criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher with a minimum day-time low of 20º Celsius or higher for two consecutive days, or;
- Environment Canada issues a forecast calling for a Humidex of 40 or higher for two consecutive days.
Extended Heat Warnings
Extended Heat Warnings are issued when one or more of these criteria are met:
- Environment Canada issues a forecast calling for a day-time high of 31º Celsius or higher with a minimum day-time low of 20º Celsius or higher for three consecutive days or longer, or;
- Environment Canada issues a forecast calling for a Humidex of 40 or higher for three consecutive days or longer.
These criteria were selected after an extensive review of epidemiological evidence led by Public Health Ontario and Health Canada about the links between temperature and humidity, and health outcomes, including mortality and illness.
The current local forecast does not call for conditions that would trigger heat alerts or warnings, however it is still important to be aware of symptoms associated with heat as illnesses can still occur in the absence of such warnings. For more information visit: http://www.healthunit.com/extreme-heat.
Media Contact:
Dan Flaherty, Communications Manager, Middlesex-London Health Unit, 519-663-5317 ext. 2469
or 519-617-0570 (cell.)
Spokesperson:
Randy Walker, Public Health Inspector, Middlesex-London Health Unit