Identifying Strategies for a Cooler Scottsdale
Welcome! Thanks for your interest in learning more about urban heat in Scottsdale and solutions for a cooler future.
Heat in Scottsdale: the basics
Heat is one of our region's top sustainability challenges. The extreme temperatures we experience in Scottsdale have far-reaching impacts on our community's health, infrastructure, environment and economic well-being.
Over the past two decades, the Scottsdale Airport has averaged 93 days each year with temperatures of at least 100°F, and 10 days with temperatures of at least 110°F. In 2020, record high numbers of hot days were reported all across the region, including 129 days above 100°F. These hot days, as well as hot nights, are expected to become more common in the coming years.
One of the major factors contributing to temperature increases in cities like Scottsdale is the "urban heat island" effect. Temperatures in cities are often higher than surrounding rural areas, especially at night. This effect occurs because surfaces like asphalt, concrete, and brick absorb and retain heat more than natural materials, and because cities have many machines like cars and air conditioners that release waste heat into the environment.
Impact of heat on health and well-being
Over exposure to extreme heat can have serious health consequences for people, including heat exhaustion and heat stroke. In surveys conducted in Maricopa County by health departments and universities, more than 25% of residents report experiencing some health problems because of the heat each summer.
Heat is by far the greatest weather-related health threat in Arizona. Since 2010, more than 3,000 Arizonans have died because of heat exposure. Record-setting heat in summer 2020 resulted in 10 heat-associated deaths in the City of Scottsdale.
Extreme heat in Scottsdale can have many impacts beyond individual health. Some of the other reasons people express concern about heat include:
-Outdoor sports and recreation activities, and shopping at outdoor markets, become less appealing and safe on hot days
-Tourists are less likely to visit when it is very warm, which can be hard on local businesses
-Sustainable transportation modes like walking, bicycling, and using public transportation become more challenging
-Outdoor work becomes tougher, and requires more breaks and changes in work schedules
Investigating heat in Scottsdale
In 2020, the City of Scottsdale partnered with Arizona State University to assess patterns of urban heat in the city and identify promising cool strategies.
One of the ways that scientists assess urban heat is by looking at satellite images of the surface temperatures. These images show the temperature of the ground, rooftops, parking lots, trees, or other objects that are first viewed by a downward-looking satellite.
The map below shows the average surface temperature across the city during the summer of 2020*. Places shown with a red color disproportionately contribute to urban heat, while places in blue have cooler surfaces. The hottest surface in Scottsdale is measured at 165°F, which is 70°F hotter than the coolest surface (95°F). Scroll down to see some examples of particularly cool and hot surfaces in the city!
*Note: Land surface temperature is derived from Landsat 8 satellite imagery which is captured at approximately 11 am local time once every other week.
Cool Example
Indian Bend Wash: This 11-mile corridor of parks, lakes, paths and golf courses is home to some of the lowest surface temperatures in the entire city.
Cool Examples
Scottsdale Civic Center and Stadium: Both of these popular attractions are home to large grass areas with intermittent trees.
Hot Example
Scottsdale Airport: The airport is a major economic driver and source of employment, but its 8,200-foot paved runway and surrounding surfaces are among the hottest in the city.
Hot Example
Scottsdale Road between Old Town and South Scottsdale: This two-mile stretch is home to many popular stores and services, but has comparatively little tree cover and natural landscaping.
Surface type drives a lot of the temperatures people experience. Surfaces with lots of hard covering, like asphalt and concrete, tend to be hotter and retain heat longer. Surfaces with lots of trees, grass, water, and shade tend to be cooler and cool down more quickly.
Use the slider below to compare land surface temperature and land cover type of the Indian Bend Wash and the surrounding neighborhoods. Click on the menu icon in the bottom left corner to see what the landscape colors mean.
Now it's your turn!
Use the map below to find somewhere interesting to you. Click on the arrow symbol on the top-right of the map to expand it on your screen. Then, try to find your neighborhood, work, a park that you use, or another feature of interest. Are these locations hot or cool?
Use the button in the top right corner of the map with diagonal arrows to expand and collapse the map for full-screen viewing. The +/- buttons in the bottom right can be used to zoom in and out of the map.
Interactive Map. Land Surface Temperature - Summer 2020.
Heat in Scottsdale's Growth Areas
Many of the project activities focused on the three Growth Areas identified in the City of Scottsdale 2035 General Plan.
According to the 2035 General Plan, the Growth Areas are “specific locations within the community that are most appropriate for development focus, and will best accommodate future growth, new development, revitalization, and redevelopment. Scottsdale’s Growth Areas focus higher intensity development, a planned concentration of land uses, and enhanced transportation and infrastructure in designated areas.”
Accordingly, the project was focused on these areas to help staff identify opportunities for mitigating heat in parts of the city that are currently developed and/or expected to see additional development in the coming years.
Due to their continuing growth and development, the three growth areas are excellent locations to consider heat mitigation strategies.
Growth Areas
Airpark
The Airpark growth area encompasses the Scottsdale Airport and surrounding commercial and residential areas. The average summertime surface temperature in the Airpark area was 132°F. The primary landscape type in Airpark includes bare soil and concrete (45%), with 8% tree coverage and 6% grass coverage.
Growth Areas
Old Town Scottsdale
Old Town encompasses the classic Old Town shopping area, including the surrounding Fashion Square Mall, Waterfront, and Scottsdale Civic Center. The average summertime surface temperature in the Old Town area was 131°F. The primary landscape type in Old Town includes asphalt (35%) and buildings (31%), with 10% tree coverage and 3% grass coverage.
Growth Areas
McDowell Rd/Scottsdale Rd
The McDowell Rd/Scottsdale Rd growth area primarily includes areas that run along McDowell Rd and Scottsdale Rd. As a result, the primary landscape type in this growth area is asphalt (48%), with 6% tree coverage, and 1% grass coverage. The average summertime surface temperature in the this area was 134°F.
Field experiments to measure heat in the growth areas
Many variables can impact how people experience heat in their environment. To assess the incoming heat to a human body, scientists will measure a number of weather-related variables, including air temperature, surface temperature, humidity, wind speed, and radiation from the sun.
To measure these variables in the city, researchers at ASU used a mobile weather station called MaRTy. MaRTy collects data that helps understand how thermally comfortable people are at a scale more relevant to people than a stationary weather station.
Here are some pictures of MaRTy measuring heat in Scottsdale over the summer.
MaRTy, the mobile weather cart, measures heat around Scottsdale over the summer.
ASU researchers took MaRTy to four different locations in Scottsdale: Old Town Scottsdale, Waterfront, Scottsdale Promenade, and Skysong.
An example of the data collected by MaRTy in Waterfront is below. As you can see, the radiant temperature (the temperature which best accounts for human thermal comfort because it includes radiation from the sun and heat from surrounding surfaces), can be very hot in certain locations—over 140°F! The radiant temperature varies a lot more than air temperature (the red line in the figures below). Radiant temperature is why you feel more comfortable in the shade than in the sun during the summer.
Data collected by MaRTy at four different times of day at Waterfront.
The thermal imagery below was collected while MaRTy was making its measurements in the Waterfront area. These images give a good sense of how different surfaces can have very different temperatures, even when side by side.
Airborne thermal images of Scottsdale
The images below show the thermal landscape of various Scottsdale locations as captured by a thermal camera from a helicopter. The air-borne images were used to assess the thermal environment at different times of day. Below, images captured at approximately 6 PM on June 21, 2021 are shown.
Thermal images of Scottsdale locations captured from a helicopter.
Strategies to make Scottsdale cooler
Analysis of the data collected for the Cooling Scottsdale project, conversations with City staff, and consultations with scientific experts led the project team to identify three broad goals for heat mitigation in the city that could help the city become a cooler and more comfortable place for residents and visitors.
The project team developed a list of 29 specific strategies that the city might pursue, such as:
- Developing a comprehensive urban forestry master plan
- Creating new tree planting and preservation requirements
- Defining staff responsibilities related to heat mitigation
- Pilot testing cool pavement materials
- Providing more shade near bicycle racks and water fountains
The three broad goals for heat mitigation are
1. Increase tree canopy in the city
Particularly along frequently traveled pedestrian walkways and along the south and west facades of buildings.
What you can do to help
- Plant a tree at your home! Local organizations like Trees Matter and Arizona Community Tree Council can help you choose a tree and learn to care for it with their free online resources. SRP customers may be eligible to receive free shade trees by attending a free workshop .
- It is important to balance the benefits of tree shade with the need to conserve water. Consider planting a tree that is drought tolerant and needs less water. If you have grass at your home, it may be worthwhile to replace the grass with a shade tree. Scottsdale offers a grass removal rebate program that may help.
- Encourage and support local businesses to plant and maintain trees on their property.
- Contact the city if you spot a tree in a public space in need of some additional care.
- Attend public meetings like zoning and redevelopment hearings to advocate for tree preservation and landscaping.
2. Reduce the land area of exposed dark asphalt, dark roofs, and other hot surfaces.
What you can do to help
- If it is time to replace your roof, ask about lighter-colored or more reflective "cool" roof materials. A free cool roof guide is available online to help you explore options. Cool roofs can help you save money on your summer energy bills and keep the city cool.
- Find ways to shade or cover any hot surfaces at your home. Even a few small plants or a shade-sail can make a difference.
- Ask business owners and landlords if they have considered cool roof materials and/or shading or replacing dark asphalt.
3. Improve and increase pedestrian shade amenities
Through building-integrated and free-standing shade structures, particularly along frequently traveled walkways and in locations that support public transportation.
What you can do to help
- If planting trees or installing shade at home, consider choosing locations that could shade the sidewalk.
- Support the Scottsdale Public Arts program that is responsible for some of the iconic public shade structures in the city.
- Take advantage of some of the city's existing shade structures by choosing to walk, bike, or use public transit.
Share your ideas with the city
Please make sure your voice is heard! The City of Scottsdale invites your feedback about heat and the proposed recommendations for achieving a cooler Scottsdale. Share your ideas in the form below!
TIP! Use the pop-out button in the top right corner of the form (box with an arrow) for an easier experience.