LAUSR

Significance Clouds play a key role in radiation and precipitation processes in the climate system. Urban-modified surface properties as well as anthropogenic heat and aerosols can alter cloud processes. How and to what extent cities interact with background conditions to impact local-regional cloud patterns remain poorly understood. Using long-term and large-scale satellite cloud observations over 447 US cities, this observational-based urban–cloud interaction research reveals cloud enhancements for most cities during warm seasons, even for smaller cities. We also found ubiquitous urban effects on cloud patterns climatologically primarily determined by climate backgrounds interacting with cities and urban surface heating. These findings advance our understanding of urban effects on regional atmospheric systems and highlight further research needs in urban hydrometeorological processes.