Extreme Heat

According to the National Weather Service, excessive heat is the leading weather-related killer in the United States. This is especially true in urban centers, where population density and building construction exacerbate the effects of excessive heat. A combination of high heat and humidity can lead to heat-related illness, including heat cramps, heat exhaustion and heat stroke.

Since 1970, Miami-Dade County has had an average increase of days above 90°F from 84 to now 133 days per year and this will continue to rise. With an average humidity in the summer of 65-70% depending on the month, a temperature of 90°F equates to a heat index of at least 103°F, which is dangerous for anyone spending time outdoors for work, athletic or recreational activities, taking public transit, walking or biking. It is especially dangerous for our elderly, young children, pregnant women, people on certain medications and/or with heart or lung conditions.

Higher temperatures also raise the cost to keep our homes and buildings cool. For lower income residents, this often results in having to make difficult choices around when and how long to use their air conditioning. The combination of hurricanes and heat presents a critical threat to the safety of the residents of our County.

Areas with lower tree canopy, impermeable and darker pavements and dense development can have average ambient air temperatures of 10-15°F more than the temperatures in a coastal area with higher tree canopy. The good news is that we can reduce this Urban Heat Island effect significantly by increasing our tree canopy, using reflective and permeable paving materials, and considering air flow with our urban design. In addition, the County and its partners can continue to improve our ability to adapt to high heat through improved early warning systems and emergency response, better access to efficient air-conditioning, and public education. In short, the County needs a Senior Executive who can analyze and co-develop heat mitigating and adaptive solutions across departments, sectors and constituencies.

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