By John Mathews
BBC Sport at Oakland Hills
The weather in Michigan has been like July (used to be) back in the UK, but the most notable rise in temperature has been among the fans.
Nothing particularly untoward has been reported back from the crowd, but there was a distinct gear change in the support they gave to the home side.
The "U-S-A!" chants were out in force, with letters split between different parts of the course at one stage.
Bizarre, but powerful and the impact it had on the US players was noticeable... for a time at least.
America's Jay Haas was among those who felt the galleries did much to inspire the US team early on after their disastrous opening performance against Europe.
Haas admitted the fans "took their gloves off", but he also credited Hal Sutton's team meeting inquest as a significant factor.
Asked how it went, Haas revealed: "Well, it was laid-back, it was jovial... and then we got our ass chewed."
Will there be anything left of their "butts" after last night's inquest though?
Information is the number one currency when things get tight at the Ryder Cup and the scoreboards around the course become focal points that have their own effect on the mindsets of the players.
A board full of red means the US team are on top, while blue indicates Europe are dominating.
Conscious of the need to protect his rookies, European captain Bernhard Langer told playing partners Paul Casey and David Howell not to look at the scoreboard unless it was full of blue.
It was hard to argue with Casey when he replied: "But how do you know if it's full of blue unless you look at the board?"
American TV commentators knew exactly what was going on in Sergio Garcia's mind when he lined up what seemed to be an irrelevant putt in the final fourballs.
Standing 50ft from the 18th hole, Garcia was expected to pick his ball up as he was only putting for bogey and playing partner Lee Westwood seemed to be the best option for Europe.
Their match with Jay Haas and Chris DiMarco was all-square and tension was high, but when Garcia opted to putt, the TV experts were in no doubt.
Sarcastically making a reference to the legendary antics of Seve Ballesteros in the past, one said: "Gamesmanship by a Spaniard in the Ryder Cup? Surely not... "
He didn't have too much to add when Garcia holed the putt from way downtown and secured Europe's half point.