Well, relatively speaking, maybe.
Monday, Barrow, Alaska smashed their record high for the day with a 26 degree reading. The old record was 21 set twice in 1917 and 1989. That follows a period earlier this month when temperatures were as much as over 20 degrees below the average of -22.
I'm betting 26 probably qualifies for short sleeves up there, and possibly a pool party, except any outdoor pools in Barrow are A) a very poor investment and B) still likely frozen solid. (Incidentally, while I've never been to Barrow, if there are any outdoor pools up there, I'd love to meet the salesman.)
On the other hand, down in tropical Hawaii, Kahului set a record low temperature was set when the temperature plummeted to 51 degrees overnight, breaking the old record of 53. That probably qualifies for at least some sort of jacket, but I'll bet any outdoor pool parties were still a go :)
One place where outdoor pools are plentiful and any parties are definitely a go this week: Arizona, which has been hot, even by their standards (for February, at least.) Tucson hit 91 on Monday, breaking their old record of 87. It was the second day in a row that Tucson was the hottest temperature recorded in the entire nation, and the 91 was just one degree shy of their all time highest February temperature.
Normally, Tucson doesn't see their first 90 degree day until April 10th.
(Thanks to UW's Mark Albright for the information.)