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Brace Yourself Hawaii, Heat and Humidity Could Last into Winter

Flickr /  hjl
Flickr / hjl

You’re not alone in thinking that it’s been a hot summer. The mercury rose to 93 degrees in Honolulu three times last month, tying the record for the hottest daily temperature for August. And as HPR’s Molly Solomon reports, the heat and humidity aren’t expected to end anytime soon.  

Just about everyone is complaining about the weather. And with good reason. "We've seen quite a few records being broken beginning in June and continuing through the summer months," said Chris Brenchley, a meteorologist with the National Weather Service.

Brenchley says temperatures in Hawai‘i are highly affected by warming waters. This summer it’s been up to 4 degrees above typical levels in the Eastern Pacific, leading to air temperatures about 3 degrees above normal. But Brenchley says the heat phenomenon afflicting the islands is caused by more than just high temperatures. "It doesn't really capture how uncomfortable it's been," said Brenchley. "Because really what is causing it to be so warm is the humidity."

Humidity levels have reached into the high 70's. That can be dangerous when combined with the record temperatures. "We saw consistently high heat index values, a measure of humidity and temperature, reaching into the high 90's and even occasionally the triple digits."

Those sweltering conditions have taken their toll on island residents. Just last week, an ‘Ewa Beach school teacher drove herself to the hospital with symptoms of heat exhaustion. And stores across the islands have reported fans and portable air conditioning units flying off the shelves. Even ice cream sales are seeing a boost: Bubbies Homemade Ice Cream & Desserts reported a 25 percent increase in sales this summer.

Forecasters say part of the problem this year has to do with light winds. "When we don't have the winds, it becomes very hot and sticky," said Hawaii State Climatologist Pao-Shin Chu, who has been studying island trade wind patterns for decades. He says Honolulu used to average 200 or more trade wind days per year, but that number has dropped to 150 days. "We lost about 25 percent of northeast trade wind days," said Chu, who believes more research is still needed to pinpoint what’s responsible for the decreasing trades.

Another uncertainty is how long the heat and humidity stay. Chris Brenchley says before the air cools, it needs help from offshore. "For temperatures around Hawaii to cool significantly, we're going to need that ocean water to cool," said Brenchley. "And sometimes that can take quite a bit of time."

Brenchley expects the unseasonably warm temperatures to remain high through late fall and into winter, likely setting more records in the months to come.

Molly Solomon
Molly Solomon joined HPR in May 2012 as an intern for the morning talk show The Conversation. She has since worn a variety of hats around the station, doing everything from board operator to producer.
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