According to the United States Census Bureau, the town has a total area of 1.57 square miles (4.07 km), of which 1.56 square miles (4.03 km²) is land and 0.015 square miles (0.04 km), or 0.98%, is water.

The record high temperature in Windermere is 101 °F, which took place in 1998, and the record low temperature is 19 °F, which took place in 1985.

A post office opened in Windermere in 1888. The post office closed in 1901, and reopened in 1911. Windermere was established as a residential development in 1889 and chartered in 1925.^{[citation needed]}

During late 2007, the town of Windermere filed a proposal to annex Isleworth and Butler Bay, both wealthy subdivisions. This was met with extensive debate from town residents and an objection from Orange County, which stood to lose millions of dollars of property tax revenue. After lengthy discussions, and battles with the county, Isleworth remained unincorporated, but Butler Bay was annexed into Windermere, with over 90% of its residents approving annexation via a mail-in ballot.

Windermere has a Town Manager / City Council form of government. Five council members are elected at large for two-year terms with three running for election in odd years and two running for election in even years along with the mayor. Gary Bruhn has served as mayor for seven consecutive terms since 2004.

Police services are provided by the Windermere Police Department. In January 2014, the department's former chief, Daniel Saylor, was sentenced to eight years in prison for perjury. He had lied to the court in order to protect a friend who was found guilty of raping children and sentenced to life in prison. Saylor had pleaded guilty to other charges in 2011, earning him a year in jail.

Fire rescue and emergency medical services are provided by the Ocoee Fire Department. Postal services are provided by the Windermere Post Office. The Floridan Aquifer is Windermere and Orange County's source of drinking and fire hydrant water, which is filtered naturally through hundreds of feet of sand and rock, and then treated by the Orange County Water Division.