Kochi Rainfall Records: Wettest Years and Monsoon Onsets since 2015

Ashraf Gents Hostel

Key facts

From 1 June to 17 August 2018, Ernakulam district recorded 2,305.9 mm of rain against a normal of 1,606.0 mm, about 43.6% above normal, according to figures compiled on Wikipedia from IMD data.
Kerala’s August 2018 rainfall was 164% above normal, according to Wikipedia’s account of the 2018 floods.
On 28 May 2024 the IMD confirmed a cloudburst at Kalamassery after its automatic weather station on the CUSAT campus recorded 103 mm of rain in one hour.
IMD defines a cloudburst as 10 cm or more of rain at a station within one hour.
Wikipedia gives Kalamassery’s average annual rainfall as about 350 cm.

The Aluva Manappuram Siva temple with its tiled roof on the sandy riverbank. Photo: Vis M / Wikimedia Commons, CC0

A wet place in an average year

Kalamassery sits between the Periyar and the Edappally–Kakkanad uplands, and it is wet even in an ordinary year. Wikipedia’s entry on the town gives an average annual rainfall of about 350 cm, with heavy rain from both the southwest monsoon (June–September) and the northeast monsoon (October–November). We have not found an official year-by-year table of annual totals for a Kalamassery station, so this page does not rank “wettest years” by total; it records the events that official sources and newspapers measured and reported.

Kalamassery does have rain stations of its own. IMD bulletins list a Kalamassery gauge among Ernakulam stations, and the Advanced Centre for Atmospheric Radar Research (ACARR) at CUSAT runs an automatic weather station that became the key witness in 2024.

Timeline of notable rain events

Date	What happened	Source
5 June 2015	Monsoon declared over Kerala	IMD onset annex
8 June 2016	Monsoon declared; joint-latest onset of the decade	IMD onset annex
30 May 2017	Monsoon declared	IMD onset annex
29 May 2018	Monsoon declared	IMD onset annex
1 June – 17 August 2018	Ernakulam: 2,305.9 mm vs normal 1,606.0 mm (+43.58%)	Wikipedia, 2018 Kerala floods (IMD data)
15–17 August 2018	Periyar basin averaged 588 mm of rain in three days	Wikipedia, citing Central Water Commission
16 August 2018	Kochi Metro services briefly suspended; Periyar discharge at Neeleeswaram peaked at about 8,800 m³/s	Wikipedia, 2018 Kerala floods
8 June 2019	Monsoon declared	IMD onset annex
1 June 2020 / 3 June 2021	Monsoon declared	IMD onset annex
29 May 2022	Monsoon declared	IMD onset annex
8 June 2023	Monsoon declared	IMD onset annex
28 May 2024	Cloudburst over Kalamassery: about 100–103 mm in an hour at CUSAT; flash floods in Kochi	Onmanorama; The Week/PTI
30 May 2024	Monsoon declared	IMD onset annex
24 May 2025	Monsoon declared, earliest since 2009	IMD press release
4 June 2026	Monsoon declared, three days late	IMD press release

Rainfall totals for 2018 are as compiled on Wikipedia from IMD figures. The full list of onset dates is on our monsoon onset dates page.

2018: the season that set the benchmark

The 2018 southwest monsoon began early, on 29 May, and ended as Kerala’s worst flood in living memory. Statewide, rainfall from 1 June to 17 August was 2,226.4 mm against a normal of 1,620.0 mm; August alone was 164% above normal. Ernakulam’s 43.58% excess was below Idukki’s 83.58%, but the water from Idukki and Idamalayar came down the Periyar to Aluva, Eloor and the Kalamassery side. Wikipedia records 35 of Kerala’s 54 dams being opened, and Cochin International Airport suspending operations in mid-August (sources give different reopening dates).

The human story of those days, including relief camps in Eloor and Aluva, is told in our 2018 floods archive page.

28 May 2024: the Kalamassery cloudburst

On the morning of Tuesday 28 May 2024, two days before the monsoon was declared, an intense storm sat over Kalamassery and Thrikkakara. CUSAT scientist S. Abhilash told reporters that the campus gauge recorded about 100 mm in an hour; early reports gave 98.4 mm in about 90 minutes. IMD at first said it had not recorded a cloudburst, then confirmed on 5 June 2024 that the event qualified, citing 103 mm in one hour at the ACARR automatic weather station at CUSAT.

Roads around Kalamassery, Edappally and Kakkanad flooded within hours. IMD noted that a comparable burst, 92 mm in an hour, had been measured at Thiruvananthapuram on 26 March 2010, so Kalamassery’s was not Kerala’s first, but Onmanorama pointed out that sparse rain gauges make earlier events hard to confirm.

Why this history matters near the NAD signal

These records explain why monsoon advice for Kalamassery stresses drains, footwear and spare time for commutes. The NAD Road signal is a few kilometres from CUSAT, where the 2024 burst was measured, and close to the Periyar side that flooded in 2018. Men looking for a room before June can check rooms at Ashraf Gents Hostel, a men’s hostel at Ashraf house, NAD Road; the monthly rate is indicative and confirmed on the call. Read our monsoon living tips and browse the history archive for related pages.

Frequently asked questions

What was the heaviest short burst of rain recorded in Kalamassery recently?

On 28 May 2024 IMD’s station at CUSAT recorded 103 mm in one hour, which IMD classified as a cloudburst.

How much rain did Ernakulam get in 2018?

From 1 June to 17 August 2018, 2,305.9 mm against a normal of 1,606.0 mm, according to figures compiled on Wikipedia.

What counts as a cloudburst?

IMD treats 10 cm or more of rain at one station within an hour as a cloudburst.

Which year was Kochi’s wettest?

We did not find an official annual ranking for a Kalamassery or Kochi station, so we do not name one. 2018 is the best-documented extreme season.

Sources

Facts about Ashraf Gents Hostel come from the hostel’s own profile and photos; rates are indicative and confirmed on the call. Last reviewed 8 October 2026. How we write these guides: editorial notes. Map embeds © Google.

Cite this guide: Ashraf Gents Hostel. “Kochi Rainfall Records: Wettest Years and Monsoon Onsets since 2015.” Published 8 October 2026. https://ashrafgentspghostel.adserr.com/kochi-rainfall-records/ Plain-text (Markdown) version · quoting with a link back is welcome.