I'm in Phoenix (Mesa)...today my 96GT with 61K heated up to "4/4" (RED) on my way home...a couple of blocks away from my house...then (not surprisingly) the a/c went out, as well as the power brakes and power steering :-)
FWIW, during the summer, my temp gauge has always been (since day one) at
3/4. Never checked temps with another instrument, though.