FALMOUTH — Steamy temperatures, a rain delay and a shrinking lead weren’t enough to trip up Ruby Haylock on Wednesday afternoon.

The 17-year-old Haylock, a recent Leavitt Area High School graduate, went into the second round of the Maine Women’s Amateur Championship at Portland Country Club with a commanding lead and emerged smaller cushion, shooting a 2-over 72 to move to 2-over for the tournament and maintain a four-shot lead over defending champion Bailey Plourde going into Thursday’s final round.

Plourde, of Sheepscot Links Golf Club, had the day’s low round with a 1-under 69, while Erin Holmes of Val Halla Golf Course shot 4-over 74 and was alone in third at 11 over. Thea Davis (78) of Hermon Meadow Golf Club is fourth at 18 over, followed by Jordan Laplume (79, 19 over) of Dunegrass Golf Club and Kim Fogel (78, 20 over) of Portland Country Club.

“I feel like on the front nine, the heat was really getting to me and it was just hard to keep the focus. I was getting pretty irritable,” said Haylock, who made three bogeys on the first nine holes but only one on the last nine. “Then on the back nine, it was a little cooler, I was much more calm, and just happy to be out there at that point.”

Haylock didn’t open the door enough for anyone except Plourde, the 2018 and 2021 champion, who broke par in just her fifth 18-hole round of the season.

“I was very confident today. I got the putter rolling, hit some good wedge shots in, just kind of made it easier,” said Plourde, 22, who had surgery on a herniated disc in her back in March. “I avoided the big numbers, which was the goal. I was focusing on par and dropped a few birdie putts. … I was very happy.”

Conditions were challenging. Temperatures reached the high-80s, and top players who played the first round Tuesday in the relative cool of the morning spent 18 holes in the full force of the afternoon heat.

“There were some holes where I was feeling it. My skin felt like it was roasting,” said Holmes, who played in the last group with Haylock and Plourde. “With the breeze, it was great. But when the breeze died down and there were no clouds in the sky, you could feel the heat.”

Plourde had two birdies on the front against one bogey and had narrowed her gap to four shots in nine holes as Haylock struggled to block out the scorching weather. Then came a reprieve, as rain moved in and immediately soaked the course, prompting an 18-minute delay with the lead group on the eighth green.

Haylock used the pause to regroup.

“I was having a really hard time with the heat and everything,” Haylock said. “But after the rain delay, I was able to kind of recollect, and I had a much better mindset on the back nine.”

She started the back with three straight pars, getting her lead back up to six shots, and then birdied the 13th by rolling in a 10-foot putt. She parred the next four holes, sidestepping a bogey on the par-3 14th with an excellent lag putt from 40 feet, then parred the 15th by reaching the green after finding the bunker with her drive.

“I knew where (Plourde) was at and I knew where I was at, but I wasn’t too focused on it,” Haylock said. “I don’t like to pay attention to that stuff too much. I was definitely trying to keep it out of mind.”

Bogeys at the 10th and 11th hurt Plourde’s momentum, but she brought herself back into striking distance with birdies at the 13th and 16th. She made a 15-foot putt on the 13th for the first birdie, and got the second when she dropped in another from between 12 and 15 feet.

“I wasn’t too focused on what (Haylock) was shooting, to be honest. I was really just trying to make pars,” Plourde said. “I know that if I make pars, I have a chance for birdie. And if those are dropping, I’m probably going to be inching a little closer.”

She’s now within reach of Haylock, but the 2020 champion from Turner Highlands Country Club is not about to watch the leaderboard.

“I’m just excited,” Haylock said. “Who knows what tomorrow holds, but I love being out here. … No complaints, that’s for sure.”

Holmes, who began the round tied with Plourde, lost ground despite shooting three strokes better than her first-round score. The Greely High graduate and former Bucknell University player notched three birdies to counter seven bogeys.

“I think I scored better but hit it worse,” said Holmes, 23. “I just wasn’t hitting my irons, I wasn’t hitting greens as much as yesterday. Luckily, I made some good up-and-downs and made some birdies, but I left myself with tough up-and-downs all day. It was a grind.”