When forecasters predicted that oppressive heat would settle over much of the South for days this month, one of the first thoughts for staff members at the Mobile Botanical Gardens was how to protect their most sensitive plants.
But with the prolonged heat stretching into the weekend, their focus has shifted to the safety of the people drawn to the gardens, particularly tourists unfamiliar with the mental and physical toll of the steamy conditions.
“This heat is a different animal,” said Robin Krchak, the gardens’ executive director, who now closes online ticket sales at noon to encourage visitors to come in the relative cool of the mornings. The few employees and volunteers who keep the gardens humming are arriving earlier or cutting their workloads short to avoid heatstroke and heat stress.
Ahead of a typically busy Fourth of July holiday period, the extreme heat has been an early test in a region already resigned to high temperatures, heavy humidity and long summers. It has strained air-conditioners, heightened the danger of outdoor work and turned some leisure activities into matters of endurance.
Temperatures recorded across the month showed that it was a much hotter June than usual, a pattern that is likely to continue as climate change, driven by human behavior and the continued burning of fossil fuels, contributes to a warming planet.
In the South, oppressive temperatures are expected to continue through Sunday in southern Texas and places along the Gulf of Mexico. Out West, an arid heat will take hold in the afternoons and push temperatures to above-average levels.
From the Gulf Coast to the Carolinas, high temperatures could hit the mid-90s to the low 100s this weekend. The heat index, a measure of what the temperature feels like when humidity is taken into account, will reach over 110 degrees in some places, creating a pervasive blanket of heat.
“It reaches a point — and today and tomorrow are going to reach that point — if it’s 115 or 120 heat index, does it really matter?” said Todd Crandall, the grounds and facilities director of the Mobile Botanical Gardens. He starts his workday earlier in this heat, he said, not only to allow time for breaks but also to let his body move more slowly.
To help keep guests cool, staff members carry bottled water and stock more watermelon- and pineapple-flavored ice fruit bars. They are also monitoring the irrigation system and the water levels in the koi pond, in case too much water has evaporated.
And the most heat-sensitive plants, including Max, a decades-old staghorn fern, and a group of orchids, have been moved from a greenhouse perch to a safer, cooler location.
While the heat could match or break seasonal records across the country, in the South the high humidity will make it especially hard for people to endure.
“It’s a slow transition for the people who live in the Deep South, particularly the western part of the Deep South, the next few days,” said Jeffrey M. Medlin, a meteorologist instructor at the University of South Alabama who previously spent more than three decades with the National Weather Service. “It’s not just going to happen overnight.”
He urged those residents to pay close attention to the heat index in order to fully gauge the effect of the heat.
In the West, humidity will be lower, but temperatures will be even higher. Central California could reach nearly 110 degrees. In the desert Southwest, temperatures could rise above 110 degrees as the first heat wave of the season takes hold. Coastal regions may see an increase in temperatures, too, but onshore winds should allow cooler conditions to prevail in most locations.
