A numerical study was conducted of the effects of two nearby urban areas, one coastal and one inland, on the local circulations and heat transport, using a 3D mesoscale incompressible and hydrostatic atmospheric model. From the analyses of observed and calculated data in the Osaka plain with the coastal Osaka urban and inland Kyoto urban areas in Japan, we confirmed that the atmosphere over the suburban area between the two urban areas was drier than over the urban areas, during the daytime hours. Our numerical experiments revealed that both a chain flow (Ohashi and Kida 2002, JAM) and valley circulation caused the dryness over the suburban area.