Here’s the BOS raw 1-min data from 6/19. They slipped a 99° in there. IIRC, the official temps (5min running means) were 95° at :50, 98° at :54, and 97° at :55. So there was a spike in there starting at :48.
Sorry missed it. It was out ahead of a rain shower so maybe there was some small scale subsidence. They also pulled 0.06” without going below 90° too. lol