A man stays hydrated while sunning himself in Portland's Monument Square in this July 2, 2018, file photo. Credit: Troy R. Bennett / BDN

It’s so hot even the low temperatures are breaking records.

The low temperature in Portland was higher on Monday than it had ever been on July 27 in any year, according to the National Weather Service. The temperature in Maine’s largest city never dipped below 78 degrees Fahrenheit.

The temperature shattered the old record of 69 degrees, which was set in 1979 and equaled in 1989.

The Portland International Jetport also set a record with the hottest that its low temperature has ever been, the weather service said. The low temperature of 78 degrees on Monday broke a record of 76 degrees that was set in 2011 and equaled last year.

Maine is in the midst of a sustained heatwave. Temperatures are expected to remain above 80 degrees for the rest of the week.