Why are air coolers not effective in coastal areas?

Air coolers are not effective in coastal areas primarily due to the high humidity levels found in these regions. They rely on the evaporation of water to cool the air, which is less effective when the air is already saturated with moisture. Instead of lowering the temperature, air coolers can make the environment feel even more uncomfortable in humid conditions. Additionally, the cooler's performance diminishes as humidity rises, making them less suitable for such climates.