Muggy describes weather that feels uncomfortably warm and damp at the same time. On a muggy summer day, the air feels thick and heavy, almost like you could wring water out of it. Your skin feels sticky, and even sitting still in the shade doesn't help much because the air itself seems to cling to you.

Mugginess happens when there's a lot of moisture (called humidity) in warm air. Unlike a dry heat where sweat evaporates quickly and cools you down, muggy air is already so full of water that your sweat just stays on your skin, making you feel gross and uncomfortable. It's the kind of weather where you step outside and immediately feel like you need another shower.

Coastal areas and places near lakes often get muggy, especially in summer. The southeastern United States is famous for its muggy weather. You might hear someone say, “It's really muggy today,” meaning the dampness makes the heat feel worse than the temperature alone would suggest. A cold glass of lemonade and a shady spot with a breeze can feel like precious treasures on truly muggy days.