Chennai: The city and several northern Tamil Nadu districts are set to experience cooler temperatures and high humidity, with increased chances of rain due to a change in wind patterns. An upper air circulation (UAC) over the Bay of Bengal has moved closer to the Tamil Nadu coast, shifting the prevailing winds to easterlies, ushering in weather conditions typically seen during the northeast monsoon.As a result, districts including Chennai, Krishnagiri, Erode, Tiruvallur, Kancheepuram, Chengalpet, Vellore, Ranipet, Tirupattur, Salem, Dharmapuri, Tiruvannamalai, Villupuram, and the Nilgiris are likely to receive rainfall on Monday.

The convergence zone associated with this system has moved closer to the northern districts of Tamil Nadu bordering Andhra Pradesh and Karnataka.Weather blogger Pradeep John said Chennai's temperatures will stay below normal, aided by the absence of hot, dry westerly winds. However, he said that residents may feel discomfort due to increased humidity brought in by the easterlies.In an unusual trend, Tamil Nadu has not recorded a heatwave so far this year. Chennai is unlikely to touch the 40°C mark this May — similar to patterns seen in 2022, 2018, and 2004. Typically, such upper air circulations and convergence zones form by late May or early June, but this year's early formation has brought pre-monsoon-like conditions ahead of schedule, he added.