Arlo Pro 2 showing fuzzy picture. Need to wipe them clear.

[KeithMcCall]

I have 4 cameras covering the outside of my property. 2 of these I have no issue with, however the other 2 are fuzzy in the mornings and I have to get ladders to go and wipe them clear. I have had them several months now and never experienced this before, even in heavy rain. Is it possible the lower temperature has affected them, although it's showing 5 degrees at the moment?  Here is a screenshot of both cameras. Any help much appreciated. 

[TomMac]

No picture yet.... but if you can wipe it off, it's prob condensation.

Some have used products like rainex ( but I have never tried so do at own risk ).