How can urban areas affect rainfall, winter fog, sunshine, and daylight?

Urban areas significantly alter local climates through the construction of artificial surfaces, the release of pollutants, and the generation of heat, a phenomenon known as inadvertent weather modification.12

Impacts on Precipitation, Fog, and Light

• Rainfall: Cities often experience 5 to 10 percent more precipitation than surrounding rural areas. This increase is driven by urban-induced wind turbulence, thermal convection from the urban heat island, and an abundance of condensation nuclei that facilitate cloud formation.12
• Winter Fog: The combination of high concentrations of condensation nuclei and specific atmospheric conditions in urban centers can increase the frequency of winter fog.2
• Sunshine and Daylight: The blanket of particulates and pollutants suspended over cities scatters and absorbs incoming solar radiation. This reduction in light, sometimes referred to as dimming, effectively decreases the amount of sunshine and daylight reaching the surface.123

These modifications are largely attributed to the alteration of natural terrain, the burning of fossil fuels, and industrial emissions, which collectively change the energy balance and atmospheric composition of metropolitan regions.12