By Niki Morock, Meteorologist
“It’s so hot…” That’s either a northerner complaining about summer in the south, or the beginning of an old joke. You know the ones. “It is so hot that the catfish are already fried when you catch them.” In fact, this is the time of year that even lifelong southerners start mumbling about the heat.
Summer is also the time of year that you hear terms like “heat index” and “real feel temperature.” What exactly do they mean, and what’s the difference? They mean the same thing. One is an accepted scientific term, and one is a marketing phrase used by one of the bigger broadcast meteorology companies to paraphrase the accepted scientific term.
The heat index is defined as “how hot it really feels when relative humidity is factored in with the actual air temperature.” You might be surprised to learn that the heat index can actually be cooler than the air temperature; although, it doesn’t happen often. Typically, around here the heat index is higher than the air temperature.
Another fact about the heat index many aren’t aware of is that the values were “devised for shady, light wind conditions.” So, in full sun, the temperature may feel much hotter than the given value for the heat index that day. Yikes!
We track the heat index because it helps give an idea of how intense and dangerous the heat can be. The higher the heat index, the more likely even otherwise healthy people can suffer from heat exhaustion or heat stroke. Pets need to be kept cool, senior citizens should be checked on, and people without air conditioning need to find a safe way to escape the heat.
Like the wind chill, different regions have different criteria for heat advisories. I saw the other day that one was posted for part of Minnesota with a lower forecast value than we would expect here. To a degree, how you handle the heat depends on what you’re acclimated to, but don’t think that means if you grew up in the Deep South, you are immune to heat exhaustion. Eventually, we all feel it.