A Rainy May Historically Means More Rain in Summer

More rain this May may mean more rain this summer

If April showers bring May flowers, what will May showers bring? Many hope it's not a rainy summer.

So far this month, rain has been recorded at Logan Airport in Boston on each of the first seven days of May. We're expecting a few more showers on Sunday, which would make that eight days in a row of measurable rain in the city. That type of stretch in May is rare. Since records began in the late 1800s, similar streaks have only been noted in 1954, 1967, 2006 and 2013.

An examination of the summers that followed each rainy May stretch revealed near normal temperatures and above average precipitation.

The summer of 1954, defined as June through August for the purpose of this data, featured an average temperature of 70 degrees. In an average summer, that value would be around 71. It rained on 36 days that year, totaling 10.92 inches. In an average summer, nine to 10 inches of rain would fall.

In 1967, the average temperature was also 70, close to the normal value. It rained on 30 days, which was exactly average, but the total of 11.69 inches was on the wet side.

The summer of 2006 brought an average temperature of 72, which was a bit above normal. It rained on 35 days, and by summer's, end 16.87 inches had accumulated.

Similar numbers were recorded in 2013. The average temperature was 73, with rain falling on 33 days. The total amounted to 15.95 inches.

So, while we can't use this as a specific forecast, we can use it as a guide and say it may not be a bad idea to keep the umbrellas around heading into the warmer months.

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