CHICAGO—A prolonged heat wave continued to affect broad areas of North America on Monday, prompting heat warnings and health advisories across multiple U.S. states and parts of Canada as forecasters warned that persistently high daytime and nighttime temperatures could increase the risk of heat-related illness.
The U.S. National Weather Service maintained heat alerts for several regions, while Environment Canada kept heat warnings in effect for parts of Saskatchewan and Alberta, where daytime temperatures were forecast to reach the low-to-mid 30 degrees Celsius with warm overnight conditions expected to persist through the weekend.
In the United States, forecasters said unusually warm overnight temperatures were a particular concern because they reduce opportunities for the human body to recover from prolonged daytime heat. The National Weather Service has warned that elevated nighttime temperatures can increase the risk of heat exhaustion and heat stroke, especially among older adults, young children, outdoor workers and people with chronic medical conditions.
The heat has coincided with other extreme weather events across the continent. Large wildfires burning in western North America and Canada have produced smoke that spread across parts of the Midwest and eastern United States, prompting air quality alerts affecting more than 100 million people in several states, according to U.S. and Canadian authorities.
Emergency management agencies and public health officials have urged residents to limit strenuous outdoor activity during the hottest parts of the day, remain hydrated, seek air-conditioned spaces when possible and check on vulnerable neighbors and relatives. Local governments in some affected communities have opened cooling centers or expanded access to public facilities to help residents escape dangerous temperatures.
The National Oceanic and Atmospheric Administration's Climate Prediction Center said forecasts indicate continued risks of extreme heat developing across portions of the Southern Plains, Desert Southwest and neighboring regions later this month as high-pressure systems remain favorable for above-normal temperatures.
Meteorologists said the combination of prolonged heat, drought in some western regions and ongoing wildfire activity has increased stress on public health and emergency response systems, while smoke and heat together have compounded health risks in several metropolitan areas.
Officials said they would continue monitoring conditions and update heat advisories and warnings as forecasts evolve over the coming days.
