Excessive Heat Threat Level |
Threat Level Descriptions |
Extreme |
"An Extreme Threat to Life and Property from Excessive Heat."
Highest heat index 120 degrees (F) or greater. |
High |
"A High Threat to Life and Property from Excessive Heat."
Highest heat index between 115 - 119 degrees (F). |
Moderate |
"A Moderate Threat to Life and Property from Excessive Heat."
Highest heat index between 110 - 114 degrees (F). |
Low |
"A Low Threat to Life and Property from Excessive Heat."
Highest heat index between 105 - 109 degrees (F). |
Very Low |
" A Very Low Threat to Life and Property from Excessive Heat."
Highest heat index around 105 degrees (F) for July and August...OR...between 102 - 104 degrees (F) for June and September...OR...between 99 - 103 degrees (F) for May and October. |
Non-Threatening |
" No Discernable Threat to Life and Property from Excessive Heat."
Warm season weather conditions are non-threatening. |
| Note: Warm season weather conditions become hazardous when the associated heat is considered to be "excessive" relative to the human body's normal temperature of 98.6 degrees (F). This occurs when heat indices reach or exceed 99 degrees (F). At this point, heat may begin to build within the body. In situations when the humidity is very low, the heat index is approximately the same as the actual ambient temperature. Your body may quickly lose fluids as sweat (the body's natural cooling mechanism) readily evaporates; dehydration can rapidly occur. In situations when the humidity is very high, body sweat may be slower to evaporate and therefore excess heat can not be efficiently removed causing a person to quickly overheat. |
National Weather Service Forecast Office
