It's another muggy day for much of southern New Brunswick as heat warnings remain in place for the fourth day in a row for many areas.
Temperatures are expected to reach 29 Celsius.
But thanks to high humidity, it feels more like 40 C, says Environment Canada meteorologist Ian Hubbard.
He said the humidex value takes the temperature and moisture in the air and represents "what it actually feels like outside."
Environment Canada explains it this way on its website: "High humidity makes people feel hotter than they would on a drier day. This is because the perspiration that cools us down cannot evaporate as quickly in moist, saturated air."
Most of the province was also under a severe thunderstorm watch for today and this evening as well.
Although the forecast is for temperatures to peak tomorrow — and the heat warning remains in effect — the humidex value is expected to be lower, explained Hubbard.
For most of southern New Brunswick, temperatures are forecast to reach 30 C, but the humidex is expected to drop to 37, he said.
Hubbard said the humidex can be thought of as the perceived temperature.
He said a 30-degree day with low humidity is much more comfortable than 30 degrees and humid, which is what we're seeing now.
Environment Canada uses a specific threshold to issue heat warnings, and those can vary from region to region, explained Hubbard.
In New Brunswick, for example, heat warnings are issued when there are two consecutive days forecast to be above 30 C, or when the humidex is predicted to be 36 or higher. And, the overnight temperature between those two days has to remain about 18 C.
So, although Tuesday's temperature was predicted to be 29 C — so below the Environment Canada threshold for a warning — the humidex was predicted to reach 40, which triggered the warning.
While it might feel hot, it's still a far cry from the hottest day on record in New Brunswick, said Hubbard.
That was 39.4 C and it was recorded in three different places — on Aug. 18, 1935, in Woodstock and Nepisiguit Falls; and on Aug. 19, 1935 in Rexton.
Since the humidex — or humidity index — wasn't in use before 1965, there's no telling what that temperature felt like.
As for July 28 historically, 2020 actually falls far short of the hottest on record. The hottest July 28 in Fredericton was 35.6 C in 1921, in Moncton it was 32.8 C in 1921, and in Saint John it was 31.7 in 1963.
New Brunswick's chief medical officer of health drew attention to the hot, humid weather, stressing that the highest humidex levels will be reached today.
Dr. Jennifer Russell said such levels increase the risk to vulnerable people, including older adults, people with chronic diseases or young infants "with no access to air conditioning or access to a place where they can cool off."
She asked New Brunswickers to frequently check in with vulnerable family members and neighbours, but to "connect in ways that respect your family bubble with physical distancing or virtual connections for those outside your bubble."
Although Fredericton didn't set up any official cooling stations, the city encourages residents "to spend a few hours in a cool place (malls, shaded park space)," said Shasta Stairs, the communications coordinator for the city.
She said select city pools and Killarney Lake Park are open for swimming.
"Due to current COVID-19 recovery phase restrictions, both Grant Harvey Centre and Willie O'Ree Place remain closed to the general public," wrote Stairs in an emailed response.
She also pointed people to the city's webpage, Extreme Heat, which includes links and tips about the heat.