2010 Metro Mitigation Plan

EXTREME TEMPERATURES
Extreme temperature events, both hot and cold, can have severe impacts on natural ecosystems,
agriculture and other economic sectors, and human health and mortality. The normal monthly
temperatures for Nashville are presented in Table 4-22 and Figure 4-20.
Table 4-22. Temperature Summary (°F)
1971-2000 National Climatic Data Center
Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Nashville
International
Airport
36.8 41.3 50.1 58.5 67.1 75.1 79.1 77.9 71.3 59.9 49.3 40.5 58.9
120
100
80
60
58.5
67.1
75.1
79.1 77.9
71.3
59.9
50.1
49.3
40
36.8
41.3
40.5
20
0
J F M A M J J A S O N D
-20
-40
Maximum Temperatures Minimum Temperatures Normal Temperatures
Figure 4-20. Normal Monthly Temperatures
High Temperatures
Temperatures that remain 10 degrees or more above the average high temperature for the
region and last for several weeks are defined as extreme heat by FEMA. Humid or muggy
conditions, which add to the discomfort of high temperatures, occur when high atmospheric
pressure traps damp air near the ground.
In an effort to alert the public to the hazards of prolonged heat and humidity episodes, the
National Weather Service devised the "heat index”. The heat index is an accurate measure of
Metropolitan Nashville - Davidson County
Hazard Identification
Multi-Hazard Mitigation Plan Page 4-65
April 2010