More than 50% of people currently live in cities with the World Bank estimating that by 2050 nearly 7 in 10 people will live in cities. Achieving green, resilient urban communities will require intensive policy coordination and investment choices. The American Red Cross is empowering people to play an active role in their future by equipping them with data tools to understand their environment and enhance advocacy efforts. In partnership with researchers at George Mason University, we are developing a community science guidebook for mapping the urban heat island effect. It will teach how to run a data collection campaign wherein volunteers map for one day during a period of hot weather by carrying inexpensive sensors recording temperature, humidity, and GPS location through their city in the morning, midday, and evening. The high resolution air temperature and humidity data outputs are then used to analyze and understand the magnitude of the urban heat island effect throughout the day and across the city.

Satellites circling the earth at regular intervals take coarse measurements of land surface temperature, or radiation being emitted from the surface; however, the fine-scale, ground-based measurements of the air from our guidebook’s methodology are often a better representation of thermal heat stress experienced by humans, allow analysis of how the distribution of heat changes throughout the day and overnight, and can show how heat collects over several days during a heat wave.

Repeatable and accessible methodologies are foundational to community science. Our guidebook includes directions for the whole process from coalition building through to analysis and map making, data pipeline tools written in Python, and even instructions to build your own sensor package using technologies like Arduino and Raspberry Pi. Open data, open tools, and open knowledge are of immense value to people working with limited resources - a constraint especially prevalent for groups focused on humanitarian, civic, environmental, and similar public-good issues.

This presentation will cover the motivations for this project, the ecosystem of existing work that we’re building on, the successes and challenges of pilot projects that occurred in Summer 2026, what we have planned next, and where to find these new resources we’re releasing.