Why Some Neighborhoods Sleep Hotter

By: Odessa Castillo, Uzair Gheewala, Sean Harmon, and Uday Lingampalli

Demo Video

Ever notice that when you sleep at night, it feels hotter? Even when your AC is on or the windows are open, the temperature inside your house feels hotter at nighttime vs. daytime. Don’t worry, what you may be experiencing is the urban heat island effect.

What is the urban heat island effect?

A phenomenon where cities are significantly warmer than surrounding rural areas (2-5 degrees on average). This phenomenon is attributed to a combination of factors, including high density, the distribution of land cover (man-made structures to natural landscape), and greenery.

What factors are most important?

Through an analysis of multiple metropolitan cities, our group seeks to analyze how the factors of greenness, land cover, and daytime surface temperature impact nighttime surface temperature. We seek to answer the question:

What factors contribute most to this phenomenon, and what can urban cities do to reverse this?

Features of Measurement

Dayttime and Nighttime Land Surface Temperature: a 15 year average across Jan 2010-August 2025

NDVI (greenness): amount of green vegetation, value range of -1 (barren areas) to 1 (high vegetation)

Land cover: physical material of Earth surface (eg. human-made vs natural material)

Within-city comparison
Urban Heat Island comparison

Reset story
Across-city comparison

What can we conclude?

As shown from cross comparing daytime surface temperature, vegetation, and land cover, all features play a role in determining night time temperature.

Key relationships:

With increased vegetation in our simulation leading to cooler nighttime temperatures across cities, it becomes more clear that a correlation exists between the three variables in decreasing night time LST. Cities could positively benefit from our conclusions. By having green initiatives and infrastructure that promotes adding more green spaces within high-temperature neighborhoods, this can lead to neighborhoods experiencing cooler nights and more comfortable sleep.