This drop in temperature is attributed to the change in wind direction from northeasterly to southwesterly. Northeasterly winds are hot in nature as they travel from hot regions of Rajasthan and Sindh and Baluchistan provinces of Pakistan.
This change in wind direction was due to a deep depression over eastcentral Arabian Sea. But now the deep depression has weakened into a low pressure area and is moving away from the Indian coast in a west-northwesterly direction.
By October 15, the winds are expected to change direction again and start blowing in a northerly direction leading to increase in day temperature and humidity.
Meanwhile, the night temperatures have risen marginally. But they will also come down in next 48 hours, when the winds change.
Whenever the night is cloudy the minimums rise due to greenhouse effect. As the outgoing long wave radiation from the earth’s surface gets trapped between the surface of the Earth and cloud.
According to the temperature data available with Skymet, Ahemdabad recorded 36°C as the maximum on October 12, which is almost 3 degrees below the maximum recorded on October 8 and 9. The minimum in the city settled 4 degrees above normal at 24.5°C on Tuesday morning.
Similarly, the day temperature in Rajkot settled at 36.3°C on October 12, which is 2 degrees below the temperature recorded on October 9. The minimum in the city settled 4 degrees above normal at 26.2°C.
This clearly indicates that maximums have been settling in the normal levels, while the night temperatures are recording above the monthly average.