Chennai has a dry-summer tropical wet and dry climate under the (Köppen climate classification). The city lies on the thermal equator and is also on the coast, which prevents extreme variation in seasonal temperature. The hottest part of the year is late May to early June, known regionally as Agni Nakshatram ("fire star") or as Kathiri Veyyil, with maximum temperatures around 35–40 °C (95–104 °F). The coolest part of the year is January, with minimum temperatures around 19–25 °C (66–77 °F). The lowest recorded temperature was 13.9 °C (57.0 °F) on 11 December 1895 and 29 January 1905. The highest recorded temperature was 45 °C (113 °F) on 31 May 2003. The average annual rainfall is about 140 cm (55 in).
From the passage provided, extract which month is the coolest in Chennai
The coolest part of the year is January