The heat index is a measure of how hot it really feels on your body when relative humidity is factored in with the actual air temperature.

The top heat index in Washington on a sultry Tuesday appeared to be 103. The heat index, the “feels-like” temperature, exceeded 100 degrees again in Washington on Tuesday, in a sort of demonstration that history does repeat itself, while also authorizing use of the expression déjà vu.

The National Weather Service has issued a three-day heat advisory affecting nearly every county in the state through Wednesday evening.

Living in Southwest Florida, residents are no strangers to warm days and high temps. But over the last week, it’s been hot. Really hot. The National Weather Service late last week issued heat index advisories for all of the Sunshine State,

Today is expected to be the peak of the heatwave with highs in the upper-90s and heat index values between 105-110°. The heat and humidity have led to unhealthy air quality.

Heat advisory issued for central North Carolina with index values up to 109°F; residents warned of heat illnesses.

Tonight, the storms will linger through the evening but will dissipate by morning. It will be warm and muggy, with lows in the middle to upper 70s. Weather Aware Through Wednesday for Dangerous Heat The areas of high pressure will keep moving west,

The combination of hot temperatures and very muggy weather will create dangerous conditions for outdoor activities each afternoon through midweek.