Here are school start dates for many Metro Atlanta districts. If yours isn't listed, and you know it, please let us know by putting it in the comments (below). ###.
To simmer is to heat to a temperature point just off boiling, generally acknowledged as somewhere around 95 degrees C or something like 195 degrees F.. - This statement is generally true. As noted above, if vapor bubbles are forming in a liquid, at least part of it is at its boiling point.
As for regulating the heat... you look at it. If you see a slow simmer, it's perfect. If you don't see it simmering, turn the heat up. If it seems to be cooking too fast, turn the heat down. These are things that become 2nd nature to someone who cooks. Generally, we cook most things like that in a 350 Deg. F (175 deg. C) oven.