If we’re already this hot, is a sweltering summer unavoidable?

There’s no doubt that so far, we’ve been broiling this June in the Miami Valley. In case you haven’t realized, we’re still talking about spring here. With summer officially beginning Tuesday, several have asked if the recent heat suggests an abnormally hot summer is inevitable. Let’s dig into the climatology and see historically what has followed after a hot June.

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To preface, we should explain the difference between “meteorological summer” and “astronomical summer.” You’re probably familiar with the latter, as the official start of summer, and you would be right. Summer officially begins Tuesday at 5:13 a.m., at which time is the “summer solstice.” At this time, the most direct rays of the sun reach their northernmost point at the Tropic of Cancer. This is the closest toward the sun that the northern hemisphere tilts, thus bringing us the longest amount of time during the year that there is daylight in the sky. On this date, the sun rises at 6:08 a.m. and sets at 9:08 p.m.: totaling 14 hours of daylight. This is five hours and 37 minutes more daylight than the winter solstice in December (the “shortest” day).

Climatologists often refer to “meteorological summer” as it’s much easier to analyze data for research purposes. Unlike the summer solstice, which doesn’t occur at the same time every year, climatologists refer to summer as beginning June 1st to August 30th every year, thus the entire months of June, July, and August (JJA).

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To examine the question of whether or not this hot June assumes a hotter than average summer ahead, we will look specifically at the “average temperature” of each day throughout June. This average temperature is calculated by taking all 24 separate hourly temperature readings for a day in June and averaging them into one daily “average” temperature. Then, averaging all thirty daily averages for June will give us one monthly average temperature for the entire month. This will be a good representation of how warm a particular June was. For this research, the same will be done with July and August, where daily average temperatures from July 1st to August 31st will be averaged together for one July/August average temperature each year.

The data analyzed were taken from the National Climatic Data Center and are considered “official” as they are subject to strict quality control standards. The data analyzed are specifically for the Dayton International airport, whose data begins in 1935.

Hottest JunesJune Average TempFollowing July/Aug AvgJuly/Aug Heat Ranking

According to the data, the hottest Junes on record were in the 1940s and 1950s, and one in 1971. As it turns out, the data suggest that June is not a great indicator historically as to how out the rest of the summer will be. In fact, according to the data, the warmest July and August on this chart that follows one of these top five hottest Junes only ranks 18th. The fourth hottest June, in 1971, was followed by the 76th warmest July and August.

As of this writing, June 2022 is on par with being the 16th hottest June on record, however, we still have 11 days to go. With more heat on the way this week, it is possible that we will continue to see this year’s June rise in the ranking, but as of right now, grab some ice cream and sit poolside because summer begins Tuesday!