Government soil mapping shows the city centre on the Ruthven–Middle Ridge soil association: very deep, dark reddish-brown clay loams over red clay subsoils with plenty of nodular laterite, a red Ferrosol on basalt. The Toowoomba–Gabbinbar association, mapped just east in East Toowoomba, is much the same deep red soil. It drains freely and holds up well, but the surface dries through summer and can turn water-repellent, leaving patches that shed water instead of soaking it in: a wetting agent fixes that, watering harder doesn't. Red Ferrosols are often on the acid side, so test before liming rather than guessing. Rainfall depends on the record: the Bureau of Meteorology's old Toowoomba station (1869 to 2007) averaged about 950 mm a year, while its Toowoomba Airport station has averaged about 740 mm since 1996, most of it in summer. July nights average 6.7 °C at the airport, so couch and kikuyu slow right down and colour off after light frosts. Buffalo and fescue suit the shadier blocks under mature street trees, with couch and kikuyu on open, sunny frontages.
Toowoomba City is the central suburb that takes in the CBD, a rough rectangle bounded by Bridge, Hume, James and West Streets, with the Mort Estate neighbourhood in its north-west. East Creek and West Creek meet just north of the CBD to form Gowrie Creek, which drains west to the Condamine River. The suburb holds 32 heritage-listed places, among them City Hall, the Empire Theatre and Laurel Bank Park. Toowoomba is Australia's second-most-populous inland city after Canberra, sits around 700 m up on the Great Dividing Range, and lives up to its Garden City name with 159 public parks and the Carnival of Flowers every September.
