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  • Shannon Carnevale

The Urban Heat Island Effect: A Growing Challenge in Florida’s Urban Areas

As an Extension Agent, a significant part of my daily work involves talking about our environment with folks from all walks of life. A topic that has recently been on everyone’s lips in the realm of urban forestry and community health is the urban heat island effect. It’s an issue that has far-reaching implications for our cities and the people who live in them. 

Now that summer feels like it is officially here, and hurricane season is upon us, I feel like everyone’s conversation has turned to how hot the weather has been. And while the season’s hottest weather is yet to come, you may have noticed it doesn’t feel equally hot everywhere in Polk County. This is especially true when you compare the evening temperatures in our more rural or natural areas to our cities like Lakeland, Winter Haven, Bartow, and Lake Wales. We can all thank the urban heat island effect for this heat disparity.

So, what is the urban heat island effect? 

Essentially, it refers to urban or metropolitan areas that are significantly warmer than their surrounding rural regions. This temperature difference is primarily due to human activities. Cities and towns are full of buildings, roads, parking lots, and other structures made of materials like asphalt and concrete that absorb sunlight during the day and release it slowly at night, leading to an overall increase in temperature. 

However, the heat island effect isn’t just a daytime phenomenon. Unlike rural areas, which cool down considerably after sunset, urban areas don’t experience the same temperature drop. The heat stored in buildings and roads keep cities warm even after the sun goes down, creating a 24/7 cycle of increased temperatures. In winter, this can feel a bit nice. While the countryside in Polk may experience freezing temperatures, it will likely stay a few degrees warmer in the cities. 

In areas with a lot of water, like Lakeland and Winter Haven, this effect can be compounded by the insulating effect large waterbodies have on the surrounding lands. Even at a statewide level, this is noticeable. It’s why Florida will look bright orange on the weather map when every other state is experiencing freezing temperatures. And, although it may seem counterintuitive, the water can have the same insulating effect in summer. When states to the north are experiencing heat waves into the triple digits, it is rarer to see those temperatures in Florida. There isn’t a lot of research about how the urban heat island effect and the insulating effects of large waterbodies work in cities with both phenomena, but hopefully, there will be in the future.

Unfortunately, the implications of the urban heat island effect are complex, and wide-ranging, and go beyond simple discomfort. For instance, as temperatures rise, so does our reliance on air conditioning, leading to increased energy consumption. Furthermore, hotter temperatures elevate the emissions of air pollutants and greenhouse gases, contributing to climate change. From a human health perspective, heat islands can lead to heat stress and other heat-related illnesses. Even our wildlife isn’t spared, as some creatures are drawn to the warmth of the roads, leading to an unfortunate increase in roadkill incidents.

As Polk County continues to urbanize, we must tackle the heat island effect head-on. But what can we do on an individual level? There are several strategies we can all take part in.

First and foremost, plant more trees. Trees are nature’s air conditioners. They absorb sunlight, provide shade, and cool the air through a process called transpiration. Additionally, trees provide a multitude of other benefits, from filtering pollutants out of the air to capturing stormwater runoff. 

However, planting a tree isn’t as simple as just digging a hole and dropping in a seedling. You need to consider where to plant it for maximum shading effect. For instance, planting a tree on the east, west, or south sides of your house can provide the most shade. If you’re unsure what type of tree to plant or how to plant it, call our office in Bartow. Your local Polk County extension office is staffed with trained master gardener volunteers who are always ready to provide personalized advice for your yard.

Beyond planting trees, we can also turn to green infrastructure. This includes initiatives like green roofs, cool pavements, and strategically planned city growth. These mimic natural systems and bring the benefits of nature into our built environments. These projects can be more expensive up front but are often less expensive in the long run when we consider energy efficiency, stormwater management, and mitigation of traditional capital projects.

Last, but by no means least, is the power of civic engagement. Let your local government know you value trees and support measures that protect and enhance our urban forests (also known as community forests). You can do this by sending an email, making a call, or attending community meetings. Every voice counts and public support for these less-traditional solutions is critical.

As we work to mitigate the urban heat island effect, it’s essential to remember that community trees and forest canopy aren’t just about cooling our cities. There’s a growing body of research showing that being around trees can lower stress levels and reduce the risk of heart disease. In short, trees make us happier and healthier. And, as new research continues to be released, I’m confident that this relationship with community trees will only get stronger.

In conclusion, combating the urban heat island effect is a complex and collective effort. We all have a part to play in planting trees, supporting green infrastructure, and championing urban and community forestry. By doing so, we can help make our cities more livable, improve public health, and protect Florida’s natural beauty.

If you’re interested in learning more about the urban heat island effect, consider listening to the Naturally Florida podcast episode on this topic at It’s episode one of season two, “Is It Getting Hotter in Our Cities? It’s the Urban Heat Island Effect!” 

If you have any questions, feel free to contact me at 


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