San Antonio could see over 100 days of +100F temperatures per year by the end of the century.
Why Adaptation Matters
The vision for San Antonio’s future is that of a resilient city, meaning a city that can maintain normal function in response to external stresses and disruptions, specifically those from climate change. One of the first exercises for SA Climate Ready was a vulnerability and risk assessment that examined how the projected changes in temperature, precipitation, and extreme weather will impact different parts of our community. That process helped us identify the populations at highest risk and community systems that will need to be addressed through the actions identified in the plan, listed below.
- Increased exposure and risk of injury to vulnerable groups from heatwaves
- Increased impacts from high ozone concentrations
- Increased infrastructure damage from wildfires
- Increased injury and mortality at low water crossings
- Increased exposure and risk of injury to vulnerable groups from precipitation
- Increased infrastructure damage from precipitation
- Increased occurrence of vector-borne diseases
- Increased need for waste and debris management
- Reduced local food security from reduced production
- Reduced abundance and health of native species and ecosystems
- Increased mobility disruption for residents and City staff
- Increased need for emergency management resources.
Days Over 100
With a changing climate we are expecting a steady rise in the number of extreme heat days (over 100 F). Under the worst projections where we fail to reduce greenhouse gases, San Antonio could have 100+ degree weather for nearly 1/3 of the year.Extreme heat will continue to exacerbate problems for San Antonio’s residents, businesses, and institutions in terms of public health, energy costs, and impacts on infrastructure. Many people with underlying health conditions experience complications when exposed to extreme heat. Outdoor work and recreation may need to be curtailed more frequently, causing economic harm. Extreme heat days also put a strain on our energy system as the demand for cooler air increases.
With a changing climate, we can also expect more nights over 80 degrees as higher levels of humidity will hold more of the heat that builds up in the daytime. At the current rate of change, we can expect 80+ degree nights to be the average rather than an extreme.
Warmer nights will mean that our most vulnerable residents will not be able to escape the heat of the day as they have in the past. Air conditioning will continue to run throughout the night for a greater part of the year, placing a larger burden on our energy supply.
Cool Pavement Reduces Urban Heat Island Effect
San Antonio can get hot. Some parts of the city, especially those with a lot of buildings and roads but not much natural shade, can get even hotter – sometimes, by as much as 20 degrees!
This is called the “urban heat island” effect.
The asphalt used to pave roads traps heat and releases it at night, making a hot city even hotter.
The water-based asphalt treatment known as cool pavement reflects more sunlight and absorbs less heat, thereby reducing spikes in temperature at night. It’s safe to use, containing no harmful chemicals, enhances the life of the pavement, and is compatible with traditional asphalt. Cool pavement looks different, too – it’s lighter and grayer in color.
In 2021, the City of San Antonio became the first city in Texas to fight heat with the treatment, testing it on a small stretch of asphalt at the east end of the Hays Street Bridge. Now, the City is expanding its initiative, applying cool pavement treatments -- GuardTop, PaveTech, GAF and SealMaster -- to sections of roadway in all 10 Council Districts.
Find out more about cool pavement and view the projects locations here on the Public Works Cool Pavement Program page.
San Antonio's Heat Vulnerability Assessment Tool
The Heat Vulnerability Assessment Tool is an interactive map of San Antonio that displays surface temperatures. Feel free to jump in! You’ll be able to compare surface temperatures by month and locate hot spots around the city.
Instructions for using the tool:
- Click on the three horizontal lines in the top left corner, select “Temperature” or “Vegetation” from the drop-down menu.
- Select “Historical Temperature.”
- Select “Year” and “Month” on the left side and slide them to a year or month of your choice.
See how the HVAT was used to select the City’s first cool pavement installation.
Heat and Air Quality
San Antonio has made great progress on improving local air quality, in particular reducing ground-level ozone. Our ability to control ozone levels through pollution reduction will be challenged as extreme heat days create better conditions for ground level ozone to form.
Persistent exposure to poor air quality is a chronic stressor for some communities which creates vulnerability to other kinds of threats, including worse outcomes associated with COVID-19. The risk associated with the combination of heat and poor air quality is a critical reason why San Antonio is working to reduce emissions and prepare for climate impacts to improve public health and overall community resilience.
Protecting Vulnerable Populations
One way to reduce vulnerability is to reduce exposure to impacts like heat waves with cooling centers. The City of San Antonio has 52 locations of cooling centers around the region. The other way is to take care of the underlying health stresses some members of our community face.
San Antonio’s Mobile Integrated Healthcare program is one way that we’re reaching into the community proactively to improve health and wellness among our most vulnerable populations to help them better manage all kinds of threats, including those posed by climate change.
City Cooling Centers
One of the best ways we can prevent heat related illness and protect public health is to provide accessible public cooling centers. That's why the City of San Antonio has opened cooling centers around town for residents to access.
Use the map embedded here to find a cooling center near you and find all the cooling resources provided by San Antonio Emergency Management on the Beat the Heat program website.
Overall, San Antonio is expected to have lower total precipitation, which will strain our water supply, natural ecosystems, and agriculture.
On the other hand, we expect that individual storm events will drop higher volumes of water, leading to increased flooding risk for many residents. For example, the likelihood of a 2-inch+ rainfall event is expected to increase from 50% in any year to 80% by the end of the century.
High Water Safety
San Antonio has many streams and drainage areas that are close to roadways and even small rain events can cause water to overtop the road, creating dangerous conditions for drivers.
Bexar County has invested in a network of sensors in known trouble areas to detect whether a road should be closed for high water. If you are unsure if a road may be closed, check real-time information on the interactive HALT map.
It only takes 12 inches of water to sweep a car off the road, so when you see water on the road; Turn Around, Don’t Drown!
Four of the 12 major risks identified in The San Antonio 2019 Vulnerability Assessment are drought related. The direct impact of low water availability is what comes to mind immediately, but drought conditions can lead to widespread vegetation die off which poses both debris management challenges as well as wildfire risk.
Lack of water reduces agricultural productivity and strains natural ecosystems which can increase contact between people and wildlife looking for water. Additionally, stagnant disconnected pools become active breeding grounds for potentially disease-carrying mosquitos.
Edwards Aquifer Protection
The Edwards Aquifer provides groundwater to over 2 million people across central Texas, making it a water resource of national importance. So much that the 4th National Climate Assessment highlights Edwards Aquifer as a case study on a critical water resources that are sensitive to both drought and flooding events due to the shallow depth of the water-holding geologic layers. In response, San Antonians and Bexar County residents have stepped up and repeatedly voted to increase protections to keep this asset in good condition for future generations.
Learn more about this history of action on San Antonio Parks and Recreation's Edwards Aquifer Page
Being Climate Ready
Resources to Stay Safe
Besides staying cool, there are a number of resources available to help each San Antonian stay ready for the challenges of a changing climate.