Curious how ,any winters they’ve been outdoors.
Valid question,
@captjoe06 .
I will admit that they do not spend too much time exposed to the elements, or any harsh environments that you mentioned.
Maybe overnight or a day or two.
I like to treat them to help with UV protection and ease of wiping clean.
Plus they look much better!
Spar varnish is another option.
In fairness to my answer, the OP does not mention anything about snow, rain, etc...
Or, covering it, or not covering it...
Just heat and cold.
What do you all use to finish and waterproof your tables?
I am making mine out of some wood of unknown type that started out as bed slats
that I would like to survive the heat of the summer and the cold of the winter in Chicago.
If I could give it some color as well that would be a plus.