The US Open tees off today but the weather is threatening to ruin it.

Newstalk Breakfast's Oisin Langan spoke to former European Tour golfer Ronan Rafferty this morning to preview the second major of the year.

Oisin started by asking him about the effect the adverse conditions will have on the challengers.

"It has certainly been very unusual weather this time of year in America," said Rafferty.

"The golf course is absolutely saturated. That can be good but it can be bad. We're used to seeing fast and hard US Open courses. The guys like them like that. That's the way the organisers like to set it up but this will be totally different. There will be a temptation to get the driver out because the wet conditions will make the fairways wider."

At one time the Merion Golf Club in Ardmore, Pennsylvania - the scene of this year's tournament - was deemed not fit for purpose in terms of hosting majors.

"It is a bit of a strange one. It's a really compact golf course with 900 yards of really mean roughs and greens," explained Rafferty.

"They're having to practice 15 minutes down the road at the first fairway of the other golf course. They're also limiting the galleries to 25,000 people a day. It's a way of trying to get some of these old golf courses back onto the rota."

And who is Rafferty tipping for glory?

Listen to the full preview below: