We have a fig tree (more like a big bush right now). It was given to us by my late father in law when it was a small branch from large mature tree. 4 years later is about ten foot tall. Every year it starts up with beautiful leaves and plenty of figs and this lasts for about two months, then within two weeks all leaves turn brown and fall off the tree along all the figs. At the same time all this is happening, new leafs come in along a new batch of figs, then the cycle repeats twice every year.
Four years and didn’t get any mature figs. BTW, we’re in Florida and this appears to always happen when the Florida heat kicks in. It gets plenty of water and we also used fruit plant fertilizer to see if it helps the mature tree.
Yes, the extreme heat change will cause the Fig to become stressed and drop it's leaves and figs.
Common issues especially in a container planted Fig.
Keeping the plant properly hydrated will help.
Here are a couple of links that will help you.