Saggydog,
If I remember right; during July and August (90's to upper 90's); mine will run around 190 to 210 while using a 5' finish mower with a 30/70 coolant/water mix. Heavier loads of course will cause higher temps, but the level of the tractor made a difference too. I have a couple of hills in my pasture that I mow and have noticed that if the tractor is tilted to the left or right will make a difference in the temp as well. I have read here somewhere that the "idiot light" comes on around 235, so I make sure that I watch the gauge and clean the screen out every time I use the tractor. I plan on using "water wetter" when I drain, clean, and refill the radiator also.