Temperatures could get low enough early Saturday morning to kill most mosquitoes and lift the outdoor organized activity ban that is in place from 5 p.m. to 8 a.m.
“It’s a high possibility of a freeze,” said Pete Bouchard, meteorologist at WHDH-TV in Boston.
Bouchard said it should get as low as 26 or 27 degrees in Hamilton and Wenham on Saturday morning. It will be below freezing for several hours, Bouchard said.
The two towns are just far enough from the coast to get the temperature below freezing. For example, along Route 127 and right on the coast from Swampscott to Manchester-by-the-Sea, temperatures may only get down to 30 to 31 degrees.
“Just a few miles inland it should get cold,” he said. “It will be cold – a real shot in the arm.”
There has been an ban on organized activities in place since Oct. 1 because of the threat of both eastern equine encephalitis and West Nile Virus. Mosquitoes with both diseases have been found in the two towns thios summer, as there was a horse infected with EEE in Essex. After that, the threat level in both towns was lifted to "critical," the highest of five levels.
"(The temperatures) should dramatically drop the mosquito population," Bouchard said, noting some will survive. "The numbers will be greatly reduced."
Hamilton Health Agent Leslie Whelan said a hard frost is needs to happen to lift the activity ban. A hard frost occurs when temperatures fall below 28 degrees for 4 hours, she said.
it will still be up to the individual Boards of Health in each town to determine whether to lift the ban “after there is evidence of a hard frost in their community.”
Whelan said that the temperatures near the coast are often more moderate for longer in the season than in western parts of the state so she doubted the Hamilton and Wenham area will be the first to have a hard frost.
“We just have to wait and see,” she said.