Kolkata sees driest July in at least seven years

KOLKATA: Climatologically, July is considered the rainiest monsoon month for Kolkata, along with August. But July 2023 has been one of the driest July months ever and certainly the worst in terms of rainfall in the past seven years. Weather scientists said absence of monsoon depression and the systems like low pressure areas, that would enhance rainfall in Kolkata, has caused this rain deficit.
While the normal rainfall amount for July in Kolkata is pegged at 387.4 mm, the city has received only 151.1 mm of rain so far, resulting in a seasonal shortfall of around 56%. And with no heavy downpour expected in the remaining two days of the month, Met officials see no chance of the deficit being made up.
The monsoon onset in Kolkata was delayed by around nine days this year when the rains hit the city on June 19 instead of June 10. Accentuating the deficit is the absence of any significantly potent weather system that triggers heavy downpour.
GK Das, director (weather) at Regional Meteorological Centre Kolkata, said that July and August are supposed to be the rainiest monsoon months for Kolkata as well as other parts of south Bengal districts.
"Systems like monsoon depression may develop in July triggering widespread heavy rain. But this month we have not encountered any depression which is rare for July. Also low pressure areas over the Bay of Bengal this monsoon are developing closer to Andhra and Odisha more often than over North East Bay of Bengal. The latter would have meant frequent rain in Kolkata and other parts of south Bengal," said Das.
July 2017 has been the rainiest July month since 2016 when Kolkata received a rain amount of 621.5 mm accounting to 60% surplus. Another July with rainfall above normal was in 2021 with 525.2 mm of rain recording a surplus of 36%. During the rest of the July since 2016, the city had encountered rainfall shortage.
Das also cited interplay between El Nino and a phenomenon called Indian Ocean Dipole (IOD) affecting the strength of monsoon in the India subcontinent. IOD, also known as Indian Nino, is an irregular oscillation of the sea surface temperature.
Barring North Dinajpur, which has 22% surplus rain, all other districts in Bengal have witnessed shortage. Leading the shortfall is Murshidabad with a whopping 67% seasonal deficit, followed by Birbhum and Kolkata.