Mumbai: June ended with Mumbai recording significantly less rainfall than its long-period average, even as the India Meteorological Department (IMD) issued a forecast for heavy to very heavy showers in the first week of July. The IMD ‘s Colaba observatory recorded 441.1 mm of rainfall between June 1 and 30 (81% of its normal June rainfall of 542.3 mm). The Santacruz observatory recorded 416.4 mm, or 77% of its June normal of 537.1 mm.Meanwhile, IMD has issued an orange alert for Mumbai, Thane and Palghar from July 1 to 4, forecasting heavy to very heavy rainfall at isolated places. Raigad has been placed under a red alert for July 2, indicating the likelihood of extremely heavy rainfall in isolated areas . “A low-pressure area is likely to form over the northwest Bay of Bengal around July 3, which is expected to trigger an active monsoon phase over central India during the week ,” said the IMD.On Tuesday, rainfall was recorded throughout the day, with the IMD Colaba and Santacruz observatories recording 25.4 mm and 14.1 mm in the nine hours ending 5.30 pm.For south Mumbai, June rainfall was the lowest for the month in the past three years. Colaba recorded 592 mm in June 2025 and 507 mm in June 2024. In the suburbs, Santacruz also received considerably less rain than the 592 mm recorded in June last year. The below-normal June rainfall doesn ‘t come as a surprise as the month saw a delayed start to the monsoon on June 23, which was the second latestarrival ever. It was only after the onset that the rain deficit for the season began narrowing. In fact, Mumbai was drenched by extremely heavy overnight rainfall in the first 24 hours of monsoon onset, as in the 24-hour period ending 8.30 am between June 23-24, IMD Colaba recorded 247.8 mm of rainfall and 224.8 mm at Santacruz observatory. The second significant shower came between June 28-29 when the IMD ‘s Santacruz observatory recorded 104 mm of rain in the 24 hours ending 8.30 am ; the Colaba observatory in south Mumbai logged just 30.4 mm.“The unusual rainfall pattern in June reflected the prevailing synoptic conditions during the month. The combination of weak monsoon westerlies and a persistent East -West shear zone prevented deep moisture penetration. Instead of sustained orographic rainfall, precipitation occurred mainly through localised, stationary thunderstorm cells, resulting in highly uneven rainfall distribution and leaving much of the ghat and interior belt significantly drier than normal ,” said weather observer Abhijit Modak.The rainfall deficit has also reflected in the catchment areas of the seven lakes supplying Mumbai, where inflows have remained poor. As of Tuesday, the combined water stock stood at just 97,666 million litres or 6.75% of total capacity, as compared to 5.82 lakh million litres or 40% on the same date last year.
