It's not "common" but it does happen regularly. I remember a thread a few years ago about A320 transcon flights during winter having this issue. The pilot/airline calculate a fuel load for the trip and as fuel costs fuel to transport they try not to carry too much more than needed to abide by the flight needs and minimum diversion fuel.
30 minutes of deicing will burn plenty & a headwind will burn even more. They may have taken off from JFK hoping to not experience so much burn during the flight and land ok but when it got too close to the risk zone the pilot diverted.
FAT is ~120 miles less than SFO. Another factor may have been flight path to avoid worse weather factors which had you closer to FAT.
http://www.gcmap.com/mapui?P=jfk-fat,+jfk-sfo