DENVER (KDVR) — The National Weather Service has issued a heat advisory for the Front Range due to triple-digit temperatures.

The heat advisory is in effect until 9 p.m. Monday.

Temperatures in the areas with heat advisories will range from the upper 90s to 105 degrees.

Here is a look at what the criteria is for a heat advisory, according to the National Weather Service:

  • When the maximum heat index temperature is expected to be 100 degrees or higher for at least 2 days and evening air temperatures will not drop below 75 degrees
  • The NWS said the criteria can vary for areas across the country, especially places that are not used to dangerous heat

The NWS said a heat advisory is issued within 12 hours of the onset of extremely dangerous heat conditions.