Peoria is set in a level tableland surrounded by gently rolling terrain on the Illinois River. The continental climate produces changeable weather and a wide range of temperature extremes. June and September are generally the most pleasant months; an extended period of warm, dry weather occurs during Indian Summer in late October and early November. Precipitation is heaviest during the growing season and lowest in midwinter.
| 40.9 square miles (2000) | |
| 652 feet above sea level | |
| January, 22° F; July, 76° F; annual average, 50.7° F | |
| 36.25 inches of rain, 25.10 inches of snow |
