Definition of heat index in US English:

heat index


  • A measure indicating the level of discomfort the average person is thought to experience as a result of the combined effects of the temperature and humidity of the air.

    • ‘I didn't really have an agenda, but I did take care of some errands that I've been meaning to run and haven't been able to, trapped in the house with the baby either by precipitation or a heat index topping 100 degrees.’
    • ‘In western Tennessee the heat index has surpassed 100 degrees.’
    • ‘Temperatures can be in the 100s during summer months, but low humidity in the 10 to 20 percent range keeps the heat index down.’
    • ‘Temperatures reached the mid-nineties on Wednesday and the heat index soared past 105 degrees with intense humidity levels.’
    • ‘Then there's the fact that the temperature heat index is supposed to climb past 103 today.’
    • ‘Just as the wind chill attempts to measure how cold it feels under certain wind conditions, the heat index tries to measure how hot it feels given the humidity.’
    • ‘Sunday's card went on as scheduled with the temperature at 93 degrees and the heat index at 104 degrees.’
    • ‘It's hard to feel inspired to do anything - much less blog - when the temperature is 95°, the heat index is 110 and the sun is curling back the shingles on the roof and turning the driveway into a strip of burning black goo.’
    • ‘Given good, well-drained soil and regular watering, hydrangeas grow rapidly and can be exposed to sun or shade, depending on the heat index of your zone.’
    • ‘At a heat index of 80-90 F., we may experience fatigue, which can lead to more severe complications.’
    • ‘The temperature was 104 degrees on the flight deck before we started some 30 jet engines, with a heat index around 120.’
    • ‘The 90 + degrees with a heat index of over 100 was getting a little old.’
    • ‘Be sure to keep water readily accessible for drinking and for helping your body cool down, check the weather for that day's heat index, and notice your body's signals.’
    • ‘The first thing I do is fetch ice ($8 for a regular-size bag), a job that is hugely important because the heat index, with the humidity and asphalt, is roughly 174 degrees.’
    • ‘Thank God for the trees that shade the tracks as the humidity was up and the heat index was 115 degrees.’
    • ‘It will also read temperature, humidity, dew-point, wet bulb temperature, wind chill index, heat index, barometric pressure and altitude.’
    • ‘An excessive heat warning is issued when a heat index of at least 105 degrees for more than 3 hours per day for two consecutive days, or a heat index more than 115 degrees for any period of time is expected.’
    • ‘Those changes could include higher maximum temperatures and more hot days over nearly all land areas, increased heat index over land areas and an increase in tropical cyclone peak wind intensities.’
    • ‘If the air warmed to 95 degrees and the dew point stayed at 71, the relative humidity would be 44% and the heat index would be 101 degrees.’
    • ‘External heat comes from a combination of environmental temperature and humidity, known as the heat index.’