Centrally located in Pinellas County, Largo touches the Intracoastal Waterway to the southwest and Tampa Bay to the northeast. Clearwater is Largo's neighbor to the north. To the northwest are the towns of Belleair and Belleair Bluffs. The City of Pinellas Park lies south of eastern Largo. Seminole lies south of western Largo.
Largo's land area is about 17 square miles including 651 acres of park lands. Largo's lowest elevation is sea level and its highest is about 69 feet. Largo has many lakes, the largest of which is Taylor Lake at 53 acres. Allen's Creek drains northeast Largo, flowing into Tampa Bay. McKay Creek flows through southwest Largo into the Intracoastal Waterway. There are several marinas and boat ramps to accomodate boaters.
Largo is served by two international airports, Tampa International Airport and St. Petersburg-Clearwater International Airport. The Pinellas-Suncoast Transit Authority provides bus service throughout Pinellas County and express service to Tampa. State Roads 686 and 688 pass through Largo to connect with Interstate 275 (Florida), which connects with I-75. US 19 and US-19A run north-to-south through Largo. A grid of county roads connects Largo with its neighbors.
Largo's winter climate is mild, and attracts many northerners or "snowbirds". Largo is located on the Pinellas Peninsula, so the climate is affected by its close proximity to the Gulf of Mexico and Tampa Bay. In the winter, it is warmer on the Pinellas Peninsula then on mainland Florida. Most of the rainfall occurs in the summer, when the sea breeze carries moisture from the Gulf of Mexico inland. Largo's record low is 22 F, recorded in December 1962. Largo's record high is 100 F, recorded in July 1995. The average day-time high during the summer is around 90 degrees, with a night-time low around 75. In the winter the average day-time high is around 73, with a night-time low around 51.