According to the
United States Census Bureau, "the balance" (that part of Marion County not
part of another municipality) has a total area of 368.2 square miles (953.5
km²)—361.5 square miles (936.2 km²) of it is land and 6.7 square miles (17.3
km²) of it is water. The total area is 1.81% water. These figures are
slightly misleading because they do not represent the entire Consolidated
City of Indianapolis (all of Marion County, except the four "excluded"
communities). The total area of the Consolidated City of Indianapolis, which
does not count the four "excluded" communities, covers approximately 373.1
square miles (966.3 km²).
At the center of Indianapolis is the One-Mile Square, bounded by four
appropriately-named streets: East, West, North, and South Streets. Nearly
all of the streets in the One-Mile Square are named after U.S. states. (The
exceptions are Meridian Street, which numerically divides west from east;
Market Street, which intersects Meridian Street at Monument Circle; Capitol
and Senate Avenues, where many of the Indiana state government buildings are
located; and Washington Street, which was named after President George
Washington. The street-numbering system centers not on the Circle, but
rather one block to the south, where Meridian Street intersects Washington
Street — National Road.)
Indianapolis is situated in the Central Till Plains region of the United
States. Two natural waterways dissect the city: the White River, and Fall
Creek.
Physically, Indianapolis is like most Midwestern cities. A mix of deciduous
forests and prairie covered much of what is considered Indianapolis prior to
the 19th century. Land within the city limits varies from flat to gently
sloping; most of the changes in elevation are so gradual that they go
unnoticed, and appear to be flat from close distances. The mean elevation
for Indianapolis is 717 feet. The highest point in Indianapolis lies at the
Marion/Boone County line, with an elevation of about 900 feet, and the
lowest point in Indianapolis lies at the Marion County/Johnson County line,
with an elevation of about 680 feet. The highest hill in Indianapolis is
Mann Hill, a bluff located along the White River in Southwestway Park that
rises about 150 feet above the surrounding land. Variations in elevation
from 700-900 feet occur throughout the city limits. There are a few
moderately-sized bluffs and valleys in the city, particularly along the
shores of the White River, Fall Creek, Geist Reservoir, and Eagle Creek
Reservoir, and especially on the city's Northeast and Northwest sides.
Indianapolis has a humid continental climate. Like most cities in the
Midwest, it has four distinct seasons. Summers are hot and humid, with
average high temperatures approaching 90 degrees. 100-degree temperature
days are not unheard of. Spring and autumn are usually pleasant, with
temperatures reaching around 18 °C / 65 °F. Winters can be long and cold,
with daily highs barely inching above freezing. Temperatures can fall into
negative digits. The rainiest months are in the summer, with average
rainfalls of over four inches per month, but these averages fluctuate only
slightly throughout the year.
The city's average snowfall is 27.5 inches.
The city's average annual precipitation is 102 cm / 40 inches.
The average July high is 86°F (30°C), with the low being 65 °F (16 °C).
January highs average 34 °F (1 °C), and lows 18 °F (-8 °C). The record high
for Indianapolis is 107.0 °F (40 °C), on July 25th, 1954. The record low is
-27 °F (-33 °C), on January 19th, 1994. Snowfall varies from about 20 to 30
inches (500–760 mm) a year.
