Weather Related Charts and Graphs

NOAAs National Weather Service Heat Index Chart

Heat Index (Apparent Temperature) - A measure of human discomfort due to the combination of heat and humidity. It is a more accurate measure than air temperature alone for estimating the risk of heat and its effects on human physiology. Exposure to full sunshine can increase the heat index by 15 degrees.

NWS Heat Index Values

OSHA has divided heat index values into four bands associated with four risk levels. These colored bands differ slightly from those appearing in the NOAA Heat Index chart, which was developed for the public. The NOAA bands have been modified for use at worksites.

NOAAs National Weather Service Windchill Chart

The NWS Windchill Temperature (WCT) index uses advances in science, technology, and computer modeling to provide an accurate, understandable, and useful formula for calculating the dangers from winter winds and freezing temperatures. The index:

*Calculates wind speed at an average height of five feet, typical height of an adult human face, based on readings from the national standard height of 33 feet, typical height of an anemometer
* Is based on a human face model
* Incorporates heat transfer theory, heat loss from the body to its surroundings, during cold and breezy/windy days
* Lowers the calm wind threshold to 3 mph
* Uses a consistent standard for skin tissue resistance
* Assumes no impact from the sun (i.e., clear night sky).