Temperature
![]() About this map:
Both high and low temperature extremes can be harmful to humans and animals. Use this map to take the proper precautions when extreme conditions exist.
![]() About this map:
Humidity or relative humidity measures the amount of water vapor in the air relative to the temperature. It is important in weather because humidity affects how humans feel. A hot, humid day feels hotter because we cannot sweat as effectively.
A cool, dry day feels colder because moisure evaporates more easily.
Use this map to determine the relative humidity for your area.
Heat Index
![]() About this map:
The Heat Index is a measure of relative discomfort due to combined heat and high humidity. It was developed by R.G. Steadman (1979) and is based on physiological studies of evaporative skin cooling for various combinations of ambient temperature and humidity.
As temperatures climb above 90 °F and humidity goes above 40 percent, conditions are ripe for heat-related illnesses. Use this map to determine when possible dangers exist due to the heat index.
Weather Fast Fact
Heat Advisory:
This is issued by your local NWS Forecast Office when the heat index is expected to exceed 105 degrees (100 degrees for New York City) but be less than 115 degrees for less than 3 hours in a day and/or when nighttime lows are forecast to remain above 80 degrees for 2 consecutive days.
|