In our post on Friday (When Will We Hit 100?), we discussed the possibility of hitting 100 yesterday (Sunday), but also that it was going to be close due to an approaching surface trough that was forecast to push across northern Utah. Specifically, we said that "if the trough is a bit slower than currently progged, then a high of 99–102 seems likely. Knock that down a couple of degrees if it's a bit faster."
The latter verified and indeed yesterday's high only reached 96ºF. The time series below shows this well. Through about 1 PM yesterday the flow war from the south with peak gusts of just over 30 mph. Then the trough went rhgouth and the wind shifted to NW-N. Note how the temperatures flattened out and decreased slightly following the frontal passage, resulting in a maximum temperature at about 1 PM. In contrast, the previous day, which didn't have such an airmass change, saw temperatures rise to a maximum at about 5 PM.
I'm sure you feel cheated out of your 100.