Was just doing temp test the other day...on a long highway run I'm around 90-92. (In 45 degree outside temp) I know in mixed driving, I'm the same as OP...around 89-95. I've seen up to 97/98.
But, what I thought was odd and hadn't noticed it before...this same trip I looked and saw I was at 80 degrees and started to freak (not too bad)...then I realized I'd been in third on the highway for 15 mins! I love third on the highway and often forget to shift! What can I say!
I know I gained 1.5 mpg replacing my stuck open therm a couple of years back...it was the only repair I did at the time. A little later I got another 1.5 mpgs replacing my fuel filter. Easy!