example of skim coating works under high humidity level. Note the water ponding on the floor which contibute high humidity to the working area.
Humidity is a very sensitive issue on some architectural works i.e painting and skim coating because it will affect the final result of the works.
It is very 'common sense'. If the environment is wet (high humidity level), the wet air will interact with the material (eg. skim coat and paint). The result will not be seen instantly but as time pass by, it will appear. Normally the yellowish water mark or in worst condition it will create water soak layer. this water soak layer will peel off later on and rectification have to be made.
Therefore, humidity level must be checked before the works started. Normally the manufacturer of the product have already set the humidity level allowed to work in. Its no point of speed up your work but later on you have to rectify it. So, to avoid double handling, just follow the manufacture's instruction which is also (normally) included in the Work Method of Statement,