Where I live, there isn't a single day that the relative humidity is below 80% since my country is surrounded by the sea and the temp. above 30 degree Celsius on most days. On a rainy day humidity gets to above 90%.
I've always used spray on primer and matte coat. However, I make it a point to give the can a good shake and warm it up either with a hair dryer or in a mug of warm water before spraying. After that I'll also speed up the drying with the hair dryer. This will prevent the "white coat of death" from forming. As for primer, I don't think you will have much issue with humidity unless of course you are spraying in the open rain haha.