Painters can successfully paint in humid conditions, but humidity levels are ideal around 40 to 50 percent or lower. While painters can still paint at levels above 70 percent, the drying time is significantly longer.
For the paint to dry, the water in the paint must evaporate either faster or at the same time as the solvents in the paint. The paint may not stick to the surface properly if it does not evaporate quickly enough. The same problems occur with oil-based paints. If the paint attempts to cure before the water is gone, then the surface is likely to need repainting.