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Is central Indiana in a heat wave? It depends on definition used

Is central Indiana in a heat wave? It depends on definition used

INDIANAPOLIS (WISH) — The National Weather Service in Indianapolis generally defines a heat wave as a period of abnormally hot and humid weather lasting two or more days.

However, some East Coast weather service offices have a more strict definition. That strict definition states that a heat wave is three or more consecutive days at or above 90 degrees.

Geographically, it makes sense why there are multiple definitions of heat waves. The state of Texas stringing together three days in the 90s is a lot different than Indiana stringing them together. Dallas averages over 100 days in the 90s while Indianapolis averages only 20.

If we use the loose definition from the National Weather Service, then central Indiana is definitely in a heat wave. With the more strict definition, we are not.

On Tuesday, central Indiana fell short of the 90-degree mark which snapped the two-day streak of the 90s earlier this week.

Number of 2023 heat waves compared to prior years

So far in 2023, Indianapolis has yet to record three consecutive days at or above 90 degrees. For reference, from 1991-2020, the city averaged from two to three separate heat waves. This year has been quite the contrast compared to the last few years here in Indianapolis. The year 2019 stacked up five different stretches of 90-degree heat for three consecutive days.

Using this more strict definition of a heat wave, the last time there was not a single heat wave in a calendar year in Indianapolis was 2014. Only four times since 1991 has there been a year without a heat wave.

Multiple days of 90 degrees are in the forecast, and we may string together those three days to qualify for a heat wave. If we fail to do so this week, chances will very much increase that Indianapolis will go without a heat wave in 2023.

Check out the latest 8-day forecast.