It was a long, hot, rainy summer. But as the end of October approaches, so do signs of a Boston fall: changing leaves, cooler air, spectators and rowers coming into town for the Head of the Charles Regatta, and perhaps even a frost.

People coming in for the Head of the Charles this weekend should expect a bit of rain starting on Friday afternoon, GBH’s meteorologist and plant expert Dave Epstein told Morning Edition co-hosts Paris Alston and Jeremy Siegel.

“It'll be generally in the 60s, so fairly comfortable, but folks may get a little bit wet who are just watching the regatta at that point,” Epstein said.

Saturday will likely bring more showers and highs in the 60s, he said.

“There may be a little bit of a gap in showers for a few hours, late morning into early afternoon, before more showers arrive,” Epstein said. “I'm not sure about that gap. I would just plan on the fact that it's probably going to be showery the entire day, but you might be able to sort of fold up the umbrella for a little bit there on Saturday.”

Sunday might see some more rain, but the bigger issue will be wind.

“The wind for the rowers is actually a bigger issue than the rain itself,” he said. “It's going to be windy out of the northwest. So the Charles will become quite choppy, especially in the afternoon, with those gusty northwesterly winds.”

A dry leaf on the grass, covered in white frost.
Frost coats leaves on a crisp autumn morning in Marlborough, Mass.
Bill Sikes AP

As the weekend comes to an end, Epstein said, he’ll be turning his attention to his non-native outdoor plants. This year’s growing season has been a long one, he said — one of the latest frosts on record.

“Monday night, behind this weather system, cold air is going to get dragged in,” he said. “So if we're going to see a frost here before November, it would be Tuesday. I think the best chance is from [Route] 128 and west.”

People who have tropical plants — like the banana plant Epstein keeps on his patio — will want to bring them inside, he said.

“I'll be spraying with horticultural oil, moving that inside for its winter home. And I will be doing that with all the tropicals,” he said. “If you do not get a frost or you just want to cover things up Monday night into Tuesday, I think things actually stay very mild next week. We're actually going to be back in the 60s by the middle of next week for some beautiful weather, warmer than average as well.”