December rainfall in Tamil Nadu

Tamil Nadu has witnessed heavy rainfall in December 2023.

What is the rainfall pattern in Tamil Nadu?

Weather conditions – The state is vulnerable to extreme weather conditions, while coastal districts experience flooding, other areas experience severe droughts.
- According to IMD, from the year 1951 to 2013, Tamil Nadu has received 47 normal, 8 excess, 6 deficient, and 2 scanty rainfall over a period of time.
Annual rainfall – About 987mm with a range varying from 317.4 mm to 1890.5 mm over the 63 years period (1951-2013).
- While Nilgiris receives the maximum average annual rainfall, Thoothukkudi and Karur receive the least.
Coefficient of variation in annual rainfall – It lies in the range of 0.21 to 0.37 (21 to 37%) across the districts of Tamil Nadu.

What is the rainfall scenario in December 2023?

Since October 1, Tamil Nadu has received 450mm of rainfall.
Surplus rainfall – Many coastal districts have already received their surplus rainfall.
- The annual rainfall of Kanyakumari is 760mm, whereas the district has already recorded 1050.7mm during October 1 – December 20, 2023.
Deficient rainfall - During the ongoing season (till December 20), only 14 districts out of total 38 have deficient rainfall.
Exceptionally heavy rainfall – It occurred in 3 districts of southern Tamil Nadu during December 17–19.
- IMD stated that these districts had received about 100 per cent or more surplus rain during these 3 days over the previous week (December 6 – 13, 2023).

24-hour time span exceptional rainfall – It was reported by nearly 40 meteorological stations across Thoothukudi (Tuticorin), Thirunelvali and Kanyakumari districts.
- For example, in Kalyanapattinam, it was 950 mm in December 18^th, which is close to the annual rainfall of Lucknow and Ambala (960 mm each) and more than the annual rainfall of Allahabad (918 mm).

What caused the record rainfall over southern TN?

Strong northeast monsoon – It remained vigorous over Tamil Nadu since mid-December, bringing in steady rain bands, especially over the south Tamil Nadu and neighbouring Kerala.
Movement of cyclonic circulation – It was developed in the southwest Bay of Bengal in December 16, located off the western Sri Lankan coast.
As this system moved westwards and reached southern Tamil Nadu, it gave impetus to the northeast monsoon winds, persisted over the southern Tamil Nadu region on December 18 and 19.
A heavy cloud convection was observed here, resulting in exceptionally heavy rainfall (more than 200mm in 24 hours) over Thoothukudi, Tirunelveli and Kanyakumari districts of Tamil Nadu and Idukki district of Kerala.

Source:

Join Our Telegram

Indian Ocean Naval Symposium (Ions) – 2023

Airgun Surrender Abhiyan

India’s Indo-Pacific Oceans Initiative (IPOI) UPSC GS-2 INDO PACIFIC – IR/PSIR

20 Nov, 25
SHARE

India’s Indo-Pacific Oceans Initiative (IPOI) UPSC GS-2 INDO PACIFIC – IR/PSIR IPOI is India’s open, voluntary and non-treaty-based maritime initiative for building a free, open, inclusive and rules-based Indo-Pacific through practical cooperation. Why in News? India’s Indo-Pacific Oceans Ini

AI Impact Summit 2026 UPSC GS-3 S&T PT-MAINS

19 May, 26
SHARE

AI Impact Summit 2026 UPSC GS-3 S&T PT-MAINS The India-AI Impact Summit 2026 positioned India as a Global South leader by shifting global AI debate from only AI safety and regulation to AI for development, inclusion and real-world impact. Why in News? India hosted the India-AI Impact Summit 2026 at B

Hong Kong Convention for Safe Ship Recycling UPSC GS-3 ENVIRONMENT PT-MAINS

27 Jun, 25
SHARE

Hong Kong Convention for Safe Ship Recycling UPSC GS-3 ENVIRONMENT PT-MAINS The Hong Kong International Convention, 2009 is an IMO treaty that ensures ships are recycled safely without unnecessary risk to human health, worker safety and the environment. Why in News? The Hong Kong Convention entered into force on 26 June 2

LeadIT 2.0: Leadership Group for Industry Transition COP28 UPSC GS-2 IR GS-3 S&T

14 Nov, 23
SHARE

LeadIT 2.0: Leadership Group for Industry Transition UPSC GS-2 IR GS-3 S&T LeadIT 2.0 is the second phase of the India-Sweden-led global initiative to support low-carbon transition in hard-to-abate industrial sectors. Why in News? The second phase of LeadIT was announced at the LeadIT Summit 2023, ho

India-EFTA Trade and Economic Partnership Agreement UPSC GS-2 IR/PSIR

03 Sep, 25
SHARE

India-EFTA Trade and Economic Partnership Agreement UPSC GS-2 IR/PSIR The India-EFTA TEPA is a comprehensive trade pact between India and four non-EU European countries — Iceland, Liechtenstein, Norway and Switzerland — aimed at boosting trade, investment, jobs, services, technology and supply-chain resilience. Wh