A MARTÍNEZ, HOST:
July was Phoenix, Ariz.'s hottest month ever. The heat was round-the-clock with nighttime lows in the 90s for most of the month. With more hot weather to come, those record-breaking warm nights are proving especially hard for people without housing. Here's KJZZ's Katherine Davis-Young.
KATHERINE DAVIS-YOUNG, BYLINE: Raquel Parra was evicted from her Phoenix apartment eight months ago and has been sleeping in a tent ever since. She grew up in Arizona. She's used to heat, but she's never had to spend nights outside before.
RAQUEL PARRA: You're still in the heat. Whether the sun goes down or not, it's still hot outside.
DAVIS-YOUNG: Parra says this summer's record hot overnight temperatures have been so bad, she's even had to call an ambulance.
PARRA: I was throwing up the whole night. I couldn't even eat nothing. I just couldn't put my head up. I was just out of it. The dehydration - it really got to me that day.
DAVIS-YOUNG: That's exactly why public health advocates and climate experts worry about warming summer nights. Jen Brady is with the climate research group Climate Central.
JEN BRADY: It really does come down to being a big health concern as far as your body resting and recovery from continuous heat.
DAVIS-YOUNG: Brady says this is a nationwide trend. Human-caused climate change is driving up summer daytime highs, but overnight lows are warming nearly twice as fast.
BRADY: We're seeing very few years where it's not increasing from year to year.
DAVIS-YOUNG: Climate Central analysis shows since 1970, summer nights in the U.S. have warmed about 2 1/2 degrees. But Phoenix's summer nights have gotten nearly 6 degrees hotter. That's in part because of explosive population growth and more paved-over surfaces that trap heat all night long. And as Phoenix's nights have warmed up, the region's unsheltered population has grown. Zelphya Ynzunza, who works at a St. Vincent de Paul daytime heat relief center, says lately, there's a line at the door each morning.
ZELPHYA YNZUNZA: You can just see it on their faces. Like, they're just, like, overwhelmed. Or they just can't wait to get in.
DAVIS-YOUNG: A day's worth of cold water bottles, she says, gets passed out within a few hours to people exhausted after nights spent outside in this heat. Raquel Parra has been cooling off here every day. But like most of Phoenix's heat relief shelters, this one's not open overnight. With nowhere else to go, Parra says she's been selling her plasma just to be able to afford to sleep in a motel.
PARRA: I'm hoping that I can manage to scrape by to get in a room tonight.
DAVIS-YOUNG: For at least one night, she's going to try to get a break from the heat.
For NPR News, I'm Katherine Davis-Young in Phoenix. Transcript provided by NPR, Copyright NPR.
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