ATLANTA, Ga. (Atlanta News First) — You’ve probably heard the phrase, “It’s not the heat, it’s the humidity” — and there’s actually real science behind that saying. This weekend, that’s exactly what will ramp up even more as temperatures climb and humidity makes it feel even worse!

So, what exactly is the heat index?

Mathematically, it involves a giant equation with lots of numbers and calculations, but we won’t bore you with the details! In essence, the heat index is the “feels like” temperature, and it involves both the actual air temperature and humidity levels. It’s what your body actually experiences when you step outside, not just what a thermometer reads.

Think of it this way: A dry 95° day in Arizona feels very different from a humid 95° day in Atlanta. That difference? That’s the heat index at work.

How humidity makes it feel hotter

When humidity is high, your body can’t cool itself as effectively. Sweat is supposed to evaporate off your skin to cool you down — that’s your body’s natural air conditioning system. But, when the air is already saturated with moisture, that sweat can’t evaporate as quickly. So, you feel hotter, your body works harder, and heat stress becomes a real concern.

This weekend in Atlanta, we’re expecting that sticky Southeast humidity to hang around alongside the heat. That’s why a 90° reading on the thermometer could feel like 98° or even 100°, when you factor in the moisture in the air.

What this means for our weekend

The heat index values in the 90s, and possibly low 100s, mean:

• Outdoor activities will feel exhausting. Even a short walk or yard work will feel more intense than the actual temperature suggests.
• Your body needs extra help cooling down. Drink more water than you think you need, take breaks in the shade or air conditioning, and check on elderly neighbors and pets.
• Heat exhaustion is possible. Watch for signs like dizziness, nausea or excessive fatigue — these are your body’s warning signs.

Stay safe:

• Drink water constantly, even if you don’t feel thirsty.
• Limit outdoor activity during peak heat hours (typically 2 p.m. to 6 p.m.).
• Wear light-colored, loose-fitting clothing.
• Never leave children or pets in parked cars.
• Take frequent breaks in air conditioning.

The good news: Monday and Tuesday will feel better, and we introduce some decent rain chances across north Georgia!