As the South Stews, temperatures will rise in the West as well

When forecasters predicted oppressive heat for days over much of the south this month, one of the first thoughts for Mobile Botanic Gardens staff was how to protect their most sensitive plants.

But with the lingering heat now extending 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,” says Robin Krchak, executive director of the gardens, which now closes online ticket sales at noon to encourage visitors to come in the relative cool of the mornings. The few staff and volunteers who keep the gardens running come earlier or reduce their workload to avoid sunstroke and heat stress.

Ahead of a typically busy Fourth of July holiday season, the extreme heat was an early test in a region already resigned to high temperatures, heavy humidity and long summers. It has overloaded air conditioners, increased the danger of outdoor work and turned some leisure activities into a matter of endurance.

In the south, oppressive temperatures are expected to continue through Sunday in southern Texas and places along the Gulf of Mexico. In the west, an arid heat will prevail in the afternoon, pushing temperatures to above-average levels.

From the Gulf Coast to the Carolinas, high temperatures could reach the mid-90s to the low 100s this weekend. The heat index, a measure of how the temperature feels when humidity is taken into account, will reach over 110 degrees in some places, creating a penetrating blanket of heat.

“It’s reaching a point — and today and tomorrow will reach that point — if it’s a heat index of 115 or 120, does it really matter?” said Todd Crandall, director of grounds and facilities at the Mobile Botanical Gardens. He starts his workday earlier in this heat, he said, not only to make time for breaks but also to allow his body to move more slowly.

To keep guests cool, staff carry bottled water and stock more watermelon and pineapple flavored ice fruit bars. They also keep an eye on 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 to a safer, cooler place.

While the heat could match or break seasonal records across the country, the high humidity in the south will make it particularly difficult for people to recover.

“Heat stroke will threaten prolonged outdoor activity,” forecasters warned in Jackson, Miss., where extremely dangerous heat stress is possible through Saturday. Most of the dangerous heat is expected to dissipate before the July 4 holiday, except for coastal areas of the Southeast.

In the west, the humidity will be lower, but the temperatures even higher. Central California can reach nearly 110 degrees. In the desert southwest, temperatures could soar above 110 degrees as the season’s first heat wave erupts. Coastal areas may also experience an increase in temperature, but onshore winds should bring cooler conditions in most locations.