Lake Tekapo is the second-largest of three roughly parallel lakes running north–south along the northern edge of the Mackenzie Basin in the South Island of New Zealand (the others are Lake Pukaki and Lake Ohau). It covers an area of 83 square kilometres (32 sq mi), and is at an altitude of 710 metres (2,330 ft) above sea level.
The lake is fed at its northern end by both the braided Godley River and Macauley river, which have their sources in the Southern Alps to the north. The snow melt from the Southern Alps is tinged with a light turquoise colour from the glacial silt. This gives Lake Tekapo its distinctive colour. To the east of Lake Tekapo lies the Two Thumb range with Mount Toby (2222m); Braun Elwert Peak (2086m); Dobson Peak (2095m) and Mount Maude (1797m) amongst the mountains over looking Lake Tekapo. On the western side of Lake Tekapo. Mount John (1031m) is closest to the town with Lake Alexandrina further north and Mistake Peak (1931m) sitting towards the head of the lake. Cowans Hill (783m) lies at the southern end of Lake Tekapo behind the township and next to the Tekapo river.
The average water temperature of the surface of the lake varies between a low of between 5.8 and 5.9 degrees Celsius in September and a high of 17 degrees Celsius in January.The lake is a popular tourist destination, and several resort hotels are located at the township of Lake Tekapo at the lake's southern end. The Lake Tekapo Regional Park, administered by Environment Canterbury, is located on the southern shore of the lake. State Highway 8 runs past Lake Tekapo at its southern end.
On a clear day, the taller snow capped peaks of Mount Cook National Park are visible from Lake Tekapo.
An astronomical observatory is located at Mount John, which is to the north of the town, and south of the small Lake Alexandrina.
Lake Tekapo is one of the sunniest places in New Zealand with annual sunshine hours averaging more than 2,400 each year.