His first mistake was to decline his caddie's offer to bring an umbrella along at the AT&T Pebble Beach Pro-Am on Friday.

After another interminably long round - exceeding five-and-a-half hours - most of it spent in steady drizzling rain, a cold and very wet Tiger Woods could only shrug.

"My dad always said, you only get wet once," he said.

Woods shot a two-under par round of 68 at Monterey Peninsula Country Club only to lose ground at the midway point.

This isn't the US Open, where the greens are near-impossible to hold; this is the old Bing Crosby Clambake and, for the pros, on soft, receptive greens like these it should be like throwing darts.

Woods just didn't have his aim on Friday.

He needs to find his range when he plays Pebble Beach on Saturday if he's to end a 30-month winless streak on the PGA tour.

"I'm going to have to shoot a low one tomorrow because some of the guys will be coming over here (Monterey Peninsula CC) and ... shooting five, six, seven, eight under," he said.

"I'm going to have to shoot a low one tomorrow to give myself a chance going into Sunday."

For the second straight day, Woods recouped about the least he could have from what was an impressive display of ball-striking, especially off the tee.

He missed just two fairways on Friday - more commendable given the nasty weather that blew in around midday - but couldn't capitalize with short irons in his hand.

It might have seemed to the layman that his putter was to blame, but Woods knew better.

"I'm hitting good putts," he said, "I'm not displeased with my putting at all."

"I just didn't hit the ball in the right spots to give myself the right looks (at birdie)."

He was looking to keep his approach shots below the pins, so he could be aggressive with the putts. Instead, he went long or left himself side hill sliding putts which, on greens that got increasingly bumpy as the day progressed, weren't exactly conducive for birdies.

"If we were putting smooth greens, it would be a totally different deal," Woods said.

"I know I can putt those in all day. But when you're putting on these, you have to put the ball below the hole to try to be aggressive and take out some of the movement."

Woods started his second round as he did his first, with a birdie.

But at the short par-three third came the first miscue. A birdie putt barely four feet long horseshoed out of the hole.

His putts grew more tentative as the day progressed. On the par-five sixth, Woods had ten feet for eagle and missed.

To compound his errors, he failed to save par on the two greens he didn't hit in regulation.

"You could still shoot six or seven under par here," he said when asked if the bad weather contributed to his haplessness.

"If you drive it well here, you're going to have a lot of wedges into these greens. Two or three of the par fives are reachable, so you definitely can post a good one here."

Certainly, Phil Mickelson did.

Mickelson, who's started the new season sluggishly, shot 65 at MPCC on Thursday to catapult into contention.

He's at seven-under par at the midway point; one stroke ahead of Woods but five shots behind runaway leader Charlie Wi.

"The back nine, when the weather came in, I don't know what happened but I started to play a lot better and make some birdies," Mickelson said.

"In the perfect conditions, I struggled."

Such is golf.

Another player in his forties - and multiple major winner - moved up the leader board, too.

Vijay Singh, who hasn't won on the Tour in four years, shot his second straight round of 68 to sit in a tie for third.

"I'm healthy," he said of his resurgence, "No more issues with my back, which is a good thing, so I'm ready to go out there and hit the ball the way I want to."

Completing the trifecta was Padraig Harrington. The three-time major champion is also four shots adrift of Wi.

Woods, meanwhile, will be channelling his stirring deeds of weekends past at Pebble Beach. He won the US Open here in 2000, as well as the AT&T Pro-Am that year. His last trip here, for the 2010 Open, culminated in a tie for fourth, the highlight of which was a Saturday round of 66.

"I had a good back nine. It was fun," he recalled.

"I've had some good moments over there. I remember in '97, I had a good weekend, came back and almost beat (Mark O'Meara). I shot 63, 64 over the weekend.

"I've had some good rounds over there, so I'm looking forward to posting one of those tomorrow."