Its climate is greatly influenced by its proximity to the Himalayas and the Thar Desert, causing it to experience both weather extremes.
Delhi's proximity to the Thar Desert results in hot, dry continental winds, called loo, at times blowing all across from the West Asian mainland, making the days feel hotter.
Since the Western Disturbance depression moves eastward (and is the reason for cyclonic occurrences in Eastern Coastal areas) by this time of the year, there is no moisture-laden wind to increase humidity.
[1] Coming from Spring, the city witnesses a spurt in day temperature around early April, whereas nights still remain pleasant.
[14] Dust storms are another feature of Delhi's summer,[15][16] and can be severe and destructive when accompanied by strong winds, particularly under cumulonimbus formation.
Post mid-June, temperatures start falling slowly, while humidity shows a gradual rise.
[12] The arrival of moisture-laden South-Western winds, travelling from the Arabian Sea marks the onset of the humid season in Delhi.
Autumn arrives by early or mid-October and is marked by a very dry ambience, warm days and pleasant nights.
Around late autumn, the variation between morning and afternoon temperatures in a day becomes considerable, and can often be more than 20 °C (36 °F), with minimum dropping to under 10 °C (50 °F) and maximum still hovering slightly under 30 °C (86 °F).
Minimum temperatures gradually enter single digits by this time of the year, while days are cool.
These cold waves are caused by a depression created by Western Disturbance, which bring cloud cover and winter rains to the Plains, and add to snowfall in the North-Western Indian Subcontinent.
By early January, when winter peaks in Delhi, the minimum temperatures plunge to the vicinity of 0 °C (32 °F),[23][24][25] though very rarely entering the negative scale.
[28] Snow is a practical impossibility for Delhi (and the rest of Northern Plains) due to very dry nature of its winter- the coldest conditions happen under clear skies when icy winds rush in from the Himalayas, and a cloud cover (which is necessary for causing snowfall) rather warms the city by trapping heat, thereby junking any possibility of snow.
Delhi's winter is marked by very dense fog (not to be confused with smog that occurs in the month of November), which dramatically reduces visibility[29] and makes days colder by cutting off sunlight.
[31] It may rain towards the end of January and the precipitation is usually accompanied by hail,[32] resulting in slight increase in minimum temperatures due to cloud cover.
The transition weather is known as Spring and is characterized by warm days, cool nights, dry ambience and lively natural surroundings.
Average temperatures show a slow, gradual rise as the wind direction shift from North-West to South-West, thereby getting warmer.
Spring ends by the latter half of March and the day temperatures exceed 30 °C (86 °F) by then,[39] marking the onset of the next summer.