What does the "heat index" mean?

Question

It says it's 94 degrees out, but it also says: "feels like" 100!!! What does all this mean?

Answer 1

The heat index is similar to the wind chill, in that it is a value calculated to give people a better idea of the "Feel-Like" temperature. In the case of the heat index, the moisture content of the air will affect the feel-like temperature when conditions are sufficiently warm and humid.

The heat index calculation is based upon shady conditions. This means that the heat index can actually be 10-15 degrees warmer if you are in the direct sunlight during a hot summer day.

Temperature Dew Point Temp. Heat Index

90------------------------ 65 --------------------- 92
90------------------------ 70--------------------- 96
90------------------------ 75-------------------- 101
90------------------------ 80--------------------- 108

The reason the humidity plays such a large factor in the feel-like temperature has to do with how your body cools itself. When you sweat, the liquid water needs energy to break its binding liquid form and become a gas. This process of evaporation steals heat energy from the air surrounding your body. When you take heat away from a source, the source cools. Thus, the air surrounding your body cools, and you cool too.

The problem is that when the air has a tremendous amount of moisture, the water will not evaporate as quickly. Thus, on a hot and humid day, your body doesn't cool as efficiently, and it must work harder to become cooler.

Answer 2

Because of the higher humidity your body can not lose extra heat as easily; sweating etc. It may be 94 degrees out but the heat index of 100 means your body would lose the extra heat at the same rate as if it was 100.

Answer 3

The heat index is basically the temperature with the humidity and it is the same thing like the wind chill factor. I hope this helps you out.

Answer 4

The heat index is what it feels like outside. It refers to how hot it feels with the humidity outside. High humidity in the air makes it feel like it's hotter than it really is.

Answer 5

It is hot, and humid. When it is dry, you can sweat, and that carries heat away. When it is humid, the air has more water in it, and the sweat does not evaporate as fast. You can not loose body heat as fast. This makes it feel hotter when it is more humid.

Answer 6

It means if feels hotter than the actual temperature, just like wind chill factor is how cold it feels with the wind not how cold it really is.

Answer 7

you already answered your question. Heat index is how it actually feels outside.

Answer 8

Wish I knew

Answer 9

This is what we refer to as a rhetorical question.

Answer 10

how the weather feels.