Winds reached 35 miles per hour at the South Course at Angus Glen Golf Club and played havoc with second-round scores.
'It was like another golf course it was so different today,' said Pak, who finished with an even-par 72 on Friday. 'This golf course is really, really hard...I'm happy to finish at even par.'
To illustrate how difficult the winds were, Pak played her approach directly into the wind at the 367-yard 11th hole. On Friday, she used a 4-iron to get on, but the day before she hit a pitching wedge.
Jones hit a 7-iron to 15 feet to set up birdie at the first, her 10th. That birdie gave her the outright lead at 11-under par, a lead she could have doubled but she missed a three-foot birdie try at the next.
She fell back to 10-under with a bogey on No. 7, after she holed a seven-footer for a six on the par-5 hole. Jones chipped her third shot over the green and took two shots to reach the putting surface from a difficult lie near a cart path.
'I was thrilled to get out there with six,' Jones said.
Robbins, who has not missed a cut all season, holed a 25-foot eagle putt at the par-5 14th to get to 10-under before parring the remaining holes.
'I'm very glad I'm not out there now,' Robbins said after her morning round in which she was one of only two players to card a sub-70 round. 'It's a total guessing game with this type of wind situation.'
Robbins three-putted the third green for bogey but she rallied with three birdies on her front side. She made a 15-footer at No. 6 and then had short birdie putts at the remaining par-5 holes on the front, Nos. 7 and 9.
Jones opened with a bogey at her first, No. 10 at Angus Glen, after her approach went into a hazard. She responded with four birdies in five holes later in her front nine.
Jones drained a seven-footer for birdie at No. 13 and followed with a three-foot birdie at No. 14 after she blasted out of a greenside bunker at the par-5 hole. She added an eight-footer at No. 15 and ran home an 18-foot birdie putt at No. 17 for a front-nine 33.
'I couldn't do anything wrong,' said Jones, a two-time winner on tour this season. 'When I didn't hit great shots, I hit great putts. I would have been just as happy with an even-par round.'
Canadian Lorie Kane and Cristie Kerr share fifth place at 6-under-par 138.
Annika Sorenstam is alone in seventh at five-under after a second-round 68.
'I was just trying to play smart, keeping the ball in the middle of the fairways and greens,' Sorenstam said.
The 36-hole cut fell at three-over 147 with 77 players qualifying for the weekend.
Full-field scores from the Bank of Montreal Women's Canadian Open