Pathanamthitta is a municipality situated in the Central Travancore region in the state of Kerala, India, spread over an area of 23.50 km2. It is the administrative capital of Pathanamthitta district. The town has a population of 37,538. The Hindu pilgrim centre Sabarimala is situated in the Pathanamthitta district; as the main transport hub to Sabarimala, the town is known as the 'Pilgrim Capital of Kerala'. Pathanamthitta District, the thirteenth revenue district of the State of Kerala, was formed with effect from 1 November 1982, with headquarters at Pathanamthitta. Forest covers more than half (1396.95 km2.) of the total area of the District. Pathanamthitta District ranks the 7th in area (2652 sq. km.) in the State.

The regions that form the town were formerly under the rule of Pandalam, which had connections with the Pandya kingdom. It is believed that Hindu God Lord Ayyappa was the King of this region. When Pandalam was added to the princely state of Travancore in 1820, the region came under Travancore administration.

Modern day Pathanamthitta District, the thirteenth revenue district of the State of Kerala was formed with effect from 1 November 1982, with headquarters at Pathanamthitta. It was formed due to the efforts made by Indian politician K. K. Nair. He is known as the founder of Pathanamthitta.

Pathanamthitta has an average elevation of 18 metres (62 ft) above sea level.

The main trunk road from south to Sabarimala starts from MC Road at Adoor via NH 183A Pathanamthitta. From The North it Starts from Thiruvalla MC Road and Continues through State Highway 7 (Kerala), The Main Eastern Highway (Punalur-Muvattupuzha Road/SH-08), Main Central Road(Kesavadasapuram-Angamaly Road/SH-01),NH 183A Kollam -Teni via Adoor- Pathanamthitta .

Pathanamthitta has a moderate climate, more or less the same as is prevalent elsewhere in Kerala. Annual temperatures range between 20 °C (68 °F) and 39 °C (102 °F). The district experiences three distinct weather conditions: winter, summer and the monsoon. The winter season is experienced from December to February and summer season from March to May. There are two rainy seasons: The South-West monsoon (June to September) and the North-East monsoon (October to November). The South-West monsoon is usually very heavy. About 75% of its annual rainfall is received during this season.

The town enjoys a tropical climate, the monsoons start in June. The months of April–May can get pretty humid. The best weather is from October to February. Pathanamthitta experiences three distinct seasons: summer, monsoon and winter. Typical summer months are from March to May. The warmest month in Pathanamthitta is April. Although summer doesn't end until May, the city often receives locally developed heavy thundershowers in May (although humidity remains high).

The monsoon lasts from June to August, with moderate rainfall. Most of the heavy rainfall in the city fall between June and July, and June is the wettest month of the year. Last weeks of June is also days of floods. The three major rivers viz Pampa, Achankovil and Manimala swell with rainwater.

Winter begins in December. December through February are the winter months. The lowest temperatures are experienced during January.

According to the latest World Health Organisation (WHO) study on ambient air quality among 123 Indian cities, Pathanamthitta was found to have the cleanest air in India, in terms of least concentration of dust particles in air[citation needed]. Two out of three least polluted cities in India are from Kerala, Kollam being second least polluted. As per the database, in Pathanamthitta, the annual mean of PM10 and PM2.5 is recorded at 23 and 10 respectively, which is closer to the recommended level of concentration of particulate matter. While a number of Indian cities are among the world's most polluted, Pathanamthitta's air quality is comparable to some of the cleanest cities in North America, Europe and Australia.
Source - Wikipedia [Feb, 2021]