Weathercatch: Summer’s high daytime temperatures get all the attention, but night can be worse

Sometimes the hardest part of a heat wave is not how hot it gets during daytime, but how hot it gets at night. After enduring long, sweltering days like Monday and Tuesday, who doesn’t want to cool off at bedtime?

Although the mercury typically dips at night, it may not be enough for our bodies after being exposed to hot temperatures throughout the day. The result is increased cumulative exposure to heat so that people, pets and buildings can’t cool down.

That means, after the sun sets, warm temperatures can have big impacts. Without air conditioning, healthy people can find it hard to fall asleep and stay asleep. And vulnerable populations such as the elderly, chronically ill, disabled and homeless are at risk for heat-related illness and even death, according to the Centers for Disease Control and Prevention.

Here in the Spokane area, we’ve got it relatively easy. Our average summer overnight lows run in the low 60s, compared to places like Miami, where they run in the upper 70s, and Phoenix in the low 80s. On July 11, 2021, the low temperature in Death Valley, California, bottomed out at a blistering 107.7 degrees, the highest low ever recorded in North America.

Occasionally, however, our summertime lows go off the rails. During last summer’s historic heatwave, the overnight temperature on June 30 never dropped below 78 degrees, making it the hottest night in the city’s history. The second-hottest low has occurred twice – 77 degrees on June 29, 2021, and again on July 27, 1928. So far this year, the warmest low temperature was 71 degrees, reached overnight on Tuesday.

Thanks to Spokane’s geographic location, we don’t have to deal with stifling humidity on top of the heated air. Humidity traps heat at night, resulting in hotter overnight temperatures.

But whether it’s Spokane or Miami, a rise in summer’s overnight temperatures appears to be a national trend, according to the National Oceanic and Atmospheric Administration.

“Nighttime temperatures are slightly outpacing daytime temperatures in the rate of warming,” the agency stated.

When temperatures rise and you don’t have air conditioning, here are some tips to help get relief during a hot night:

• Increase your intake of water or sport drinks (electrolyte balance is also important), regardless of your activity level.

• Keep curtains, blinds and windows closed during the day.

• Open windows at night only if the air feels cooler outside than inside.

• Take a cool shower or bath.

• Place a cold washcloth or frozen water bottle on your wrists, ankles or at your neck, where blood vessels are closer to the surface of the skin.

• And remember, if it’s hot for you, it’s hot for your pet. Make sure your animals stay hydrated and as cool as possible.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: ldweiford@gmail.com.