20° can be a damaging/even killer temperature, especially for above ground, potted figs which have no insulating surrounding soil to protect them like in ground figs have.

Your Celeste got a big shock. Be glad it came through.

Moses

It's handled colder for longer before without any problems. Indeed, got the best 'harvest' following the coldest winter, so that didn't seem to be an issue.. I used to have two *huge* figs of unknown variety that produced volumes of sweet fruit. Even made wine for many years. But our area's all-time, record low of -3F ended that....

When in spring with buds on tree still dormant cold weather will bring about a delay and or kill them especially if those unopened buds are starting to turn green .

Martin