Aug 15, 2023 - News

Tips for staying cool on hot nights

Illustration of a scorched pillow.

Illustration: Maura Losch/Axios

Even with soaring daytime temperatures this week, it's lingering nighttime heat that can exacerbate the health risks and hazards of hot weather, according to the National Weather Service (NWS).

Why it matters: When the temperature remains high overnight, heat accumulates, there is less time to recover and physical stress multiplies, NWS meteorologist Matthew Cullen told Axios.

Driving the news: Daytime temps are expected to hit near 90 degrees in Seattle Tuesday and Wednesday and over 100 degrees in Portland, but it's the warm nights that prompted NWS to issue hazardous heat warnings for western Washington and Oregon this week, Cullen said.

  • On Monday, the overnight low in Seattle was 71 degrees, which is tied for the second-warmest nighttime temperature ever recorded in the city and the warmest since the unprecedented heat wave of June 2021, he said.
  • Overnight lows are expected to remain in the upper 60s through mid-week compared to the average minimum of 58 for this time of year, Cullen said.
  • Portland's overnight low is forecast to be 75 degrees Tuesday, compared to August's 30-year average low of nearly 59 degreesĀ  or even last year's August average of 63, NWS Portland meteorologist Gerald Macke told Axios.

Be smart: Here are some tips for staying cool at night.

  • Foods that contain mint can have a cooling effect because the menthol oil gives a cool sensation as it evaporates while being eaten, according to registered dietitian Kelly Morrow with the University of Washington School of Medicine.
  • Add salsas or cayenne pepper to your evening meals this week as spicy foods help you sweat, which helps you stay cool, Morrow says.
  • Hang wet sheets in front of open doors and windows. Evaporative cooling is a natural phenomenon and has been used in the Middle East for centuries.

Plus: The soles of the feet, the palms of the hands and the forehead contain special blood vessels, called arteriovenous anastomoses, that bypass capillaries, according to Craig Heller, a professor of biology at Stanford University. So putting cool water on them will bring body temperatures down, per Heller, though icy cold constricts blood vessels and is counterproductive.

  • But don't put cold water on the back of your neck, because the brain's thermostat could be tricked into thinking you're already cool and shut down other cooling methods, per Scientific American.

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