NYT's David Leonhardt notes a couple developments.:

According to NASA, 2010 is on course to be the planet’s hottest year since records started in 1880. The current top 10, in descending order, are: 2005, 2007, 2009, 1998, 2002, 2003, 2006, 2004, 2001 and 2008.

And:

Yet when United States senators and their aides file into work on Wednesday, on yet another 90-degree day, they may be on the verge of deciding to do approximately nothing about global warming. The needed 60 votes don’t seem to be there, at least not at the moment.

UPDATE: Sun weather blogger Frank Roylance says:

A 100-degree reading or higher on Saturday would be the sixth triple-digit day so far this summer. That's only happened three times since record-keeping began here in 1871. There were six 100-degree days in 1900, and seven in 1930 and 1988. Stay tuned.

UPDATE: The Intrade contract on whether 2010 will be among the top-five warmest years ever measured is trading around 95 (it pays off at 100), basically suggesting that bettors see it as a sure thing.