Olivia Fennell, 7, of Peaks Island, walks past the setting sun while trick-or-treating dressed as a dog on Island Avenue on Thursday night. Ben McCanna/Staff Photographer

Temperatures in Greater Portland hit 77 degrees Thursday, an unusual – but not unheard of – Halloween heatwave.

Halloween 1946 saw a high of 80 degrees in Portland, and that record has held since, according to the National Weather Service.

“This is definitely above-average temperatures for this time of year,” said Stephen Baron, a meteorologist at the weather service’s office in Gray. But “we were all surprised to see that the record today in Portland is 80.”

The average low Halloween temperature in Portland between 1981 and 2010 is 34.8 and the average high is 53.4 degrees, according to data collected by the weather service.

But while Portland came just under its record, Baron said Augusta “climatologically shattered” its previous record high Thursday. There, the day’s high of 77 degrees was well above the previous record of 69 degrees, which was set in 1956, Baron said.

“That’s pretty significant for temperatures records,” Baron said. “Usually we see them beat by one or two degrees. To be almost 10 degrees warmer is pretty good.”

Maine is predicted to have an unusually warm start to November, with a forecasted high of 72 degrees in both Portland and Augusta Friday. But temperatures will likely fall back in line with expectations next week, Baron said.

Coastal Maine is slated to see temperatures in the high 40s and low 50s this weekend, with highs in the low 40s anticipated in northern parts of the state, according to the weather service.