Wow thats a lot of miles without a rebuild! I do know how cooling systems function, been a car guy for 21 years, I was thinking about the oil when the engine is at 230. Its clear that your car is mantained well to last that long. Good job!
I'm not sure about humidity, I look at it this way, wind chill only affects objects that lose water through a membrane(skin). Buildings and cars don't see wind chill, so high humidity and hot air sucks for us but maybe not for cars...or my head could be up my a$$ again!
The grill block is held on with white duct tape(white car) so I can pull over and take it off if it gets too hot
Bad news today, your tank mileage goes in the crapper if you need to replace all of your control arm bushings! Driving it up onto the ramps to get a jack under the front end(car is too low) eats away at some of the gains I made. I was at 33.2 now its 31.5