That's just one year though. Look at 2019, 3 90 degree days, 10 at 88/89. I'd bet if you averaged it out 88-89 has more days than 90s. Plus, looking at last year when looking at the 88/89 days that's based on two temperatures, while we reached 5 different temperatures in the 90s (90, 91, 92, 93 and 94). So, thirteen days reached two different temperatures and 17 days reached five different temperatures. I'd say 88/89 is more common.