The general theme of World Cities Day is Better City, Better Life, while each year a different sub-theme and a location for its global observance is selected, to either promote successes of urbanization, or address specific challenges resulting from urbanization.

The theme for World Cities Day this year is Adapting Cities for Climate Resilience. Cities worldwide are increasingly suffering the effects of climate-related disasters, such as floods, droughts, sea level rise, heatwaves, landslides and storms.  At least 130 port cities with over one million inhabitants are expected to be affected by coastal flooding and the one billion people in urban informal settlements are particularly at risk.

Creating more sustainable, climate-resilient societies involves addressing a range of issues including poverty reduction, ensuring basic services livelihoods, the provision of accessible, affordable and adequate housing, investing in infrastructure, upgrading informal settlements and managing ecosystems. Successful, well-governed cities greatly reduce climate-related risks for their populations.