My fridge just dropped its temp to 18 degrees.

Refrigerator temperature may also change due to the door being opened too often, someone else changing the temperature settings. It could also be caused by a failed electrical component.

I had the same trouble with telephone answering machines - every thunderstorm and I would need a new one...

Lightning strikes and near misses and power outages can create mains borne voltage spikes and surges that frequently damage sensitive electronics. These days almost everything is a computer or contains a computer that uses extremely sensitive CMOS chips.

Electronics manufacturers don't make things better than they need to be for obvious reasons and so it is up to the user to protect appliances from damaging surges by using the most expensive of these with a surge protector and by using an area protector.

Since the penny dropped and I invested in a surge protector I haven't needed to replace my answering machine...

That is highly possible. Lightning can hit miles away from you and ruin your electronics. I would suggest that you contact your insurance company about it because it could be expensive to repair.

am having the same problem, and same circumstance. Did you find a solution?

You have either a sealed system problem or a control board problem. It's difficult to know which is which. You will need a qualified technician to determine what the problem is.
Good luck

sounds like power surge, could b many different things. your homeowners will cover if you call them and tell them it happened during storm hope this is helpfull

fridge temp should be 30 to 35 degrees/freezer -1 to -5 f or between 2 to 5 C for fridge and -18 to -22 C for freezer several times a day is too often...... try once every 2 days without opening door in between checks....

If the unit is a thermoelectric unit it can be the cooling system.
If the unit is a compressor unit it will be the thermostat.

I would chech the components on the compressor. Take the cover off the compressor power terminals and inspect the relay for damage.The power outage is not a concern but the power surge could definately be the cause. hope this helps.

The only thing that will make it cool to low is a thermostat. They wear out and get out of calibration. Check to be sure the temp sensor from the thermostat is tight on the mount. Its the little tube that connects to the evaporator that makes the thermostat work.