Heat Records
Heat Wave Records Explained: Duration, Nighttime Heat, Humidity, and Health Risk
How heat wave records are measured, why hot nights matter, and why humidity and duration can be more dangerous than one hot afternoon.
Quick answer: Heat wave records can involve maximum temperatures, warm nights, duration, humidity, heat index, or population health impacts.
Duration
Several days of heat can be more dangerous than one record high because buildings, pavement, and bodies do not cool enough.
Power demand also builds during long events.
Nighttime heat
Warm nights reduce recovery time, especially for people without air conditioning.
Minimum temperature records matter for health.
Humidity
Humidity slows evaporative cooling from sweat.
That is why heat index can better describe stress than temperature alone.