The sky turned cloudy around 4:30pm and gusty winds swept the national capital.
The sudden change of weather in Delhi forced airport authorities to divert at least 10 domestic flights, an official said. Vistara's Srinagar-Delhi flight was diverted to Amritsar and its Lucknow-Delhi flight was sent to Lucknow due to the inclement weather.
However, the relief to Delhi residents came after a sweltering day, when the maximum temperature had reached 40.60 degrees Celsius, a notch above the normal, the meteorological department official said. Humidity during the morning hours was recorded at 60 per cent, the official added.
Thunderstorm over the northern hill-states and its effect in the plains is due to a western disturbance, the IMD said.
"Thunderstorm accompanied with gusty winds are also very likely at isolated places over Punjab, Haryana, Chandigarh, Delhi, west Uttar Pradesh, Vidharbha, Chhattisgarh, Bihar, Telangana, north coastal Andhra Pradesh, south interior Karnataka, Tamil Nadu, Puducherry, Lakshadweep and Kerala," the IMD said in an advisory said.