This has been a very bad year for both filamentous algae and chara in this part of Virginia (Rockbridge County). And a fellow I know has had bad watermeal problems with his pond this year as well.
We've had an unusually hot and humid summer. But perhaps the big difference from last year is the night-time low temperatures. A weather writer in the Roanoke TIMES noted that the average night-time low temperatures this summer were a full four degrees warmer than the summer of 2004 -- quite a difference.
Since I have trout in my small spring-fed pond (they've made it through so far!), I've tried to avoid copper-based algaecides and started with a non-copper treatment called GreenClean ... just tried a small test area on my pond today and will see how it works out. Also had to break down and apply a colorant to my pond in mid-August just to slow up the chara.