This report describes the typical weather at the Indira Gandhi International Airport (New Delhi, India) weather station over the course of an average December. It is based on the historical records from 1996 to 2012. Earlier records are either unavailable or unreliable.
New Delhi has a hot semi-arid steppe climate. The area within 25 mi of this station is covered by croplands (87%) and built-up areas (9%).
The month of December is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 77°F to 66°F over the course of the month, exceeding 81°F or dropping below 57°F only one day in ten.
Over the course of December, the length of the day is essentially constant. The shortest day of the month is December 26 with 10:19 hours of daylight; the longest day is December 1 with 10:27 hours of daylight.
The earliest sunrise is at 6:57am on December 1; the latest sunset is at 5:36pm on December 31; the latest sunrise is at 7:14am on December 31; the earliest sunset is at 5:24pm on December 4.
Daylight savings time (DST) is not observed in 2012.
The median cloud cover ranges from 7% (clear) to 20% (mostly clear). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 13% from the start to the end of the month.
On December 1, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 67% of the time, and overcast or mostly cloudy 7% of the time.
On December 31, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 23% of the time, and clear or mostly clear 45% of the time.
The average probability that some form of precipitation will be observed in a given day is 5%, with little variation over the course of the month.
Throughout December, the most common forms of precipitation are thunderstorms, light rain, and moderate rain.
Thunderstorms are the most severe precipitation observed during 54% of those days with precipitation. They are most likely around December 16, when it is observed during 3% of all days.
Light rain is the most severe precipitation observed during 20% of those days with precipitation. It is most likely around December 6, when it is observed during 1% of all days.
Moderate rain is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around December 31, when it is observed during 2% of all days.
Either snow is exceptionally unlikely to fall at this location in December or this station does not reliably report precipitation types.
The relative humidity typically ranges from 34% (comfortable) to 94% (very humid) over the course of a typical December, rarely dropping below 24% (dry) and reaching as high as 100% (very humid).
The air is driest around December 1, at which time the relative humidity drops below 37% (comfortable) three days out of four; it is most humid around December 30, rising above 94% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical December, the dew point typically varies from 42°F (dry) to 51°F (very comfortable) and is rarely below 35°F (dry) or above 59°F (comfortable).
The time of the month between December 1 and December 31 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of December typical wind speeds vary from 0 mph to 9 mph (calm to gentle breeze), rarely exceeding 14 mph (moderate breeze).
The highest average wind speed of 4 mph (light breeze) occurs around December 30, at which time the average daily maximum wind speed is 8 mph (gentle breeze).
The lowest average wind speed of 3 mph (light air) occurs around December 1, at which time the average daily maximum wind speed is 8 mph (gentle breeze).