It's been a thing once, at least in an official, record-keeping capacity. In Fort Yukon, AK it hit 100F in 1915, but the accuracy of that reading is still in question.

That said it is pretty normal for Fairbanks and other parts of the interior to get up in the high 80s/low 90s in the summer (before dipping down to the -20s/-30s for the winter).