If you feel like it has been hotter than usual, you’re right.
While temperatures were typically in the low 90s, it felt like it was 110 degrees thanks to high indexes. And that’s why the National Weather Service issued a heat advisory for South Florida on Tuesday — its first South Florida summer advisory in seven years — across Miami-Dade and Broward counties.
Even though South Florida has seen higher July temperatures, the heat index is why this week feels so hot, said Arlena Moses, a meteorologist with the National Weather Service.
“The heat index is based on not just the high temperature, but on what the dew point or what the humidity is,” Moses said. “It may have been hotter [in years past], but the overall humidity was lower.” The city record: 100 degrees, set in July 1942.
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And it wasn’t just South Florida.
More than 70 heat-related advisories and watches were issued across the country Tuesday, with some in place until Wednesday evening. The advisories warn against high, life-threatening temperatures for more than a few hours, with the minimum temperature varying in different parts of the country. On Tuesday, states from Texas to Pennsylvania faced temperatures as high as 100 degrees and heat indexes as high as 115 degrees.
In Florida, the high heat indexes are because of a combination of hot temperatures and high humidity, both relatively normal for a South Florida summer. But with winds keeping the typical summer storms away, there’s very little to keep temperatures from rising.
“That cloud cover and rain [typically] hold down our high temperatures. We’re really not going to be seeing [those conditions] for the remainder of the week,” Moses said.
With heat indexes expected to remain above 100 degrees for the rest of the week, Larry Kelly, another National Weather Service meteorologist, couldn’t rule out the possibility of another heat advisory later this week.
“It’s going to be a hot week,” Kelly said. “We’re not going to get much of a relief from rainfall.”
The concern with the high temperatures and heat indexes, both meteorologists said, is the possibility of heat strokes for people spending time outside in the summer sun.
Heat stroke, considered a medical emergency, happens when the body’s internal temperature rises above 106 degrees. Symptoms include heat cramps, heat exhaustion, nausea, vomiting or dizziness.
It’s something Miami Fire Rescue spokesman, Capt. Ignatius Carroll, said firefighters are always aware of, especially if they have to respond to fires in their gear.
“We’re usually prepared for anything, especially if the heat index has risen,” he said.
To avoid the heat, Carroll advises people to stay indoors when possible, wear lightweight clothing and drink lots of water. If someone is affected by the heat, he said it’s important to cool the body off with ice, shade or a cold shower.
“It’s important to respond to the needs of your body when you’re dealing with heat-related issues,” Carroll said.
If heat stroke symptoms occur, he says to call 911.
Although Carroll was unaware of heat-stroke reports Tuesday, he said there were three different calls involving people opening fire hydrants — an unauthorized way of cooling off in the heat. The practice could result in a citation.
“It’s probably safer to use a garden hose to cool off than to open a fire hydrant,” Carroll said. “The pressure could injure someone, and that’s not the kind of water you want to be splashing in or get in your mouth. You don’t know where it’s coming from.”
At Zoo Miami, the concern is for both the humans and the animals they’ve come to see. Zoo staff has added fans and tarps in the animal holding areas, and is on the look out for signs of dehydration, said spokesman Ron Magill.
“The fortunate thing for us is that most of the animals are from a tropical or subtropical region. They’re used to temperatures like this,” Magill said. “It presents more of a discomfort than a real threat as long as we provide them with some help.”
More water stations have been installed across the zoo, and people are encouraged to take advantage of the shaded areas and benches and enjoy the park.
“We try to tell people, use a little bit of common sense,” Magill said. “There’s no rush in getting through the zoo.”
Temperatures will remain in the mid-90s for the rest of the week, with low temperatures dropping to the low-80s in the evenings, according to the National Weather Service forecast. The chances of rain remain less than 20 percent through the end of the weekend.
And although there’s a hot week ahead, it likely won’t compare with North America’s record-setting reading on July 10, 1913, in Death Valley, California, according to Weather.com. It was 134 degrees — without a heat index.
Miami Herald staff writer Jordan McPherson contributed to this report.