Muggy/ˈmʌɡi/ Definition 1 of 1Pro Tip 1/3Weather Specific Use 'muggy' to describe hot, moist air, often found in summer or tropical climates. Every morning this week has been muggy and overcast. Pro Tip 2/3Physical Discomfort 'Muggy' often implies the weather causes discomfort or a sticky feeling on the skin. I feel all sticky and gross because it's so muggy today. Pro Tip 3/3Not Rainy Muggy weather does not necessarily mean it's raining, but implies a high level of humidity in the air. It hasn't rained, but it's really muggy out.