I've also gotten that on warmer days when i'm in traffic but it cools off pretty quickly once i get moving.
From the Peanut Gallery: I recall that's why some cars I've owned had to run synthetic oil - because the higher operating temps (which also help burn more polutants) will break down conventional oil. I assume it's similar in this case. Of course we're talking internal engine temps versus radiator temps but i guess the point is that a higher thermostat temp allows the engine to run hotter.
Stop and Go really runs the temp up. Saw 221 degrees on a very hot day in heavy traffic, it did not boil over or lose any coolant and the temp came right down once I started moving so it must be able to handle it.
Mine gets up that high even on a cool day if im stuck in enough traffic. My fans kick on at 225 and will keep it cool no problem but i dont really like it. Personally i would like to seee the fans come on at a lower temp than what they do. I wonder if anyone has put in a lower temp switch or a controller?