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What makes it an 'official' heat wave?

Posted at 12:06 PM, Jul 09, 2024

A a heat wave is about to hit Montana, but some parts of the country define a heat wave differently than others.

A heat wave means it's hot no matter where you are. For the next two weeks, Montana will face temperatures in the 90s and low 100s, unbearable heat for some in big sky country. but ask someone from Texas or Arizona about our heat, and they might need to put a sweatshirt on.

Heat waves are specifically relative to different regions of the world. Generally, a heat wave is defined as a prolonged period of excessively hot weather, with different conditions depending on the region, as it compares to the average temperature. Montana and many northern United States areas define a heat wave of at least three days with high temperatures at 90 or greater.

However, Helena's average high temperature maxes out at 89 at the peak of summer, so average weather at that time could almost be defined as a heat wave.

A definition based on the heat wave index is the daily maximum temperature of more than 5 consecutive days exceeds the average high temperature by 9 degrees Fahrenheit.

Either way, it is going to be a long hot road we will be traveling down. Stay hydrated and stay cool. temperatures in the cities will almost certainly be warmer than surrounding areas, by as much as 20 degrees in the evening, so getting out of town might be a cool idea.