Fall officially began Saturday night, and the weather is right on-season.

“It’s looking really nice for this weekend and well into the work week,” according to Alan Dunham, a meteorologist at the National Weather Service.

In Boston, the mercury got to 73 degrees just after 2 a.m. before dropping gradually to a low of 68 at 3:59 p.m., meteorologist Kim Buttrick said.

An overnight low going into Sunday will likely be in the low 50s, Dunham said.

Outside of Interstate 495, the overnight low could be even cooler with temperatures as low as the mid-40s, Dunham said.

The autumnal equinox falls at 9:54 p.m.


“There’s going to be a noticeable autumnal chill [Sunday] and into Monday,” Buttrick said.

In Boston, highs will likely hit the upper 60s Sunday before a cool day Monday comes with a high in the upper 50s, Dunham said.

High temperatures in the upper 60s are expected to return Tuesday and Wednesday, along with a chance of rain.

Lucas Phillips can be reached at lucas.phillips@globe.com.