Thanjavur district is in the east coast of Tamilnadu. The district lies between 78° 45’ and 70° 25' of the Eastern longitudes and 9° 50' and 11° 25' of the Northern Latitudes. Thanjavur is situated in the Cauvery delta, at a distance of 314 km (195 mi) south-west of Chennai and 56 km (35 mi) east of Tiruchirappalli. The District is bound by Coleroon on the North which separates it from Ariyalur and Tiruchirapalli district; Thiruvarur and Nagapattinam districts on the east; Palk Strait and Pudukottai on the South and Pudukottai and Tiruchirapalli on the West. The city has an elevation of 57 m (187 ft.) above mean sea level. The area of the district is 3396.57Sq.Km.
Thanjavur is located at 10.8°N 79.15°E The tributaries of river Cauvery, namely, the Grand Anaicut canal (Pudhaaru), Vadavaaru and Vennaaru rivers flow through the city. Thanjavur is situated in the Cauvery delta, at a distance of 314 km (195 mi) south-west of Chennai and 56 km (35 mi) east of Tiruchirappalli.
While the plains immediately adjoining the Cauvery river have been under cultivation from time immemorial, most of Thanjavur city and the surrounding areas lie in the "New Delta" – a dry, barren upland tract which has been brought under irrigation during the early 19th century. To the south of Thanjavur city, is the Vallam tableland, a small plateau interspersed at regular intervals by ridges of sandstone.
The period from November to February in Thanjavur is pleasant, with a climate full of warm days and cool nights. The onset of summer is from March, with the mercury reaching its peak by the end of May and June. The average temperatures range from 81 °F (27 °C) in January to 97 °F (36 °C) in May and June. Summer rains are sparse and the first monsoon, the South-West monsoon, sets in June and continues till September. North-East monsoon sets in October and continues till January.
The rainfall during South-West monsoon period is much lower than that of North-East monsoon. North-East monsoon is beneficial to the district at large because of the heavy rainfall and the Western ghats feeding the river Cauvery. The average rainfall is 37 inches (940 mm), most of which is contributed by the North-East monsoon.