Storing watches

[Dee436]

I have 5 nice watches that I wear in rotation.
But, in January I am going to be away from home for 2 months.
I don't think taking all 5 watches would be the best idea with multiple flights, customs and a hotel room that has no safe so I will take maybe two.
I have just bought a small steel underfloor safe (12"x8"x8" approx) to put the ones i leave behind in.
The watches will be inside Oakley watch vaults which will then be put in the safe.
Am I likely to have problems with humidity?
Guess the divers watches would be ok anyway but the others?
Was thinking of putting some silica gel in with them maybe insulating the outside of the safe too.
Going to fit it this weekend so will get an idea over the next 5 weeks or so if it gets damp in there before I put the watches in.
Guessing others have come across this before and might have some ideas?