Actually, it's the opposite of that. Warm air is able to contain more water. Cool air holds less. Bring temps down and humidity will follow.Humidity is also directly related to temp. Lower temps and your humidity will come up. 80% humidity is a bit much. Durring vegging I prefer a range of 60 to 70 percent and 40 to 50 during flowering.
it all depends on the amount of air flow and freash air to prevent mold.Actually, it's the opposite of that. Warm air is able to contain more water. Cool air holds less. Bring temps down and humidity will follow.
That's why we use humidifiers indoors in the winter and not summer.
Overall, humidity should be one of the least important factors you need to consider.
Your humidity is fine at 40%. You do not want it at 60 - 80% unless you want mold on and in your walls and possibly in your buds. Lower your temps with ventilation or using an air cooled hood or both.
Good luck