Billy Gayton generally waits until he sees someone else set up on a frozen lake before he heads out for a day of ice fishing.

Thanks to a late-autumn frigid snap, ice has begun to form on bodies of water across central Maine. Monday was the first day Gayton, 29, was able to drop a line through a hole in the ice close to his Leeds home. He was out with his friend Eric Crowley, who lives in Monmouth, not far from Cochnewagon Lake, and keeps a close eye on the annual progress of the ice.

Every year, ice fishermen, skaters and snowmobilers are at the mercy of when the weather allows them to kick off the winter outdoor recreation season. Some years, the season starts late and doesn’t last long; during others, it begins even before winter officially does. According to the calendar, winter arrives this year at 11:28 a.m. Thursday.

Gayton said plenty of people were out on the ice on Sunday, but the Maine Warden Service is urging people to check the ice first.

“The only thing you can do is check it with an ice chisel,” said Cpl. John MacDonald, spokesman for the Maine Warden Service. “The little snowstorms we’ve had have obscured the top of the ice, and it gives a false impression of safety.”

Generally speaking, ice should be at least 2 inches thick to support the weight of a human, MacDonald said.

But all ice is not created equal.

“In southern Maine, in Cumberland and York counties, you have 3 to 4 inches of ice. It’s not the best because some rain and snow is mixed in,” he said, and that affects the structure of the ice so that it doesn’t support as much weight.

The best ice, he said, is clear ice, like ice cubes from the freezer; but it’s not yet widespread.

“You need cold nights, night after night,” he said. “It’s clear and you can see down into the water.

On Monday, the ice on Cochnewagon Lake was thick and clear.

“You could see right through it,” he said.

Crowley, 30, said he went out to check the ice Saturday.

“I stomped on it and made a crack that went out across the ice,” he said. He opted not to go fishing, but he said he noticed Saturday evening that someone had cut holes in the ice.

“Anything under 10 feet (deep) will start to freeze up in the first or second week of December,” he said. “Usually, you can get out on the ice at the end of the second week.”

The deeper the water, the longer it may take for ice to form.

“You have to be a lot more careful early in the season,” he said.

Neither Crowley nor Gayton have fallen through the ice, and both carry ice picks to help them get back on if they ever do.

“I’ve come close a couple of times,” Crowley said. “It’s a definite heart stopper.”

He went out on Maranacook Lake one winter and found 16 inches of snow on top of 2 inches of ice. During the day, water soaked into the snow.

“It created some weight, the ice settled and I heard this ear-splitting crack,” he said.

He used a skimmer to reach across the ice and reel in his trap before clearing out.

MacDonald said the warden service offers safety tips , particularly because schools will be going on winter break, and children are likely to get out on the ice for skating or hockey as well as ice fishing. The warden service recommends checking the thickness of the ice in several places using an augur or a chisel; going out with a friend or partner so if something happens, someone will be there to help; avoiding areas with currents, around bridges and pressure ridges; and if you fall in, don’t panic, but reach for solid ice.

James Brown, a National Weather Service meteorologist in Gray, said temperatures are expected to moderate toward the end of this week.

For Gayton, it’s not a big concern.

“It will soften up the ice,” he said. “It softens, then refreezes. It will be stronger. That’s what I’ve been told through an old-timer I have been fishing with.”