This report describes the typical weather at the North Las Vegas Airport (Las Vegas, Nevada, United States) weather station over the course of an average September. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Las Vegas, Nevada has a hot desert climate. The area within 25 mi of this station is covered by shrublands (94%) and built-up areas (4%).
The month of September is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 98°F to 88°F over the course of the month, exceeding 103°F or dropping below 79°F only one day in ten.
Over the course of September, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 1:05 hours, implying an average day-over-day decrease of 2.2 minutes.
The shortest day of the month is September 30 with 11:49 hours of daylight; the longest day is September 1 with 12:55 hours of daylight.
The earliest sunrise is at 6:13am on September 1; the latest sunset is at 7:07pm on September 1; the latest sunrise is at 6:36am on September 30; the earliest sunset is at 6:25pm on September 30.
Daylight savings time is observed in 2012 but it neither starts nor ends in September, so the entire month is in daylight time.
The median cloud cover is 0% (clear) and does not vary substantially over the course of the month.
On September 15, a representative day, the sky is clear or mostly clear 91% of the time, partly cloudy 2% of the time, and mostly cloudy or overcast 4% of the time.
The average probability that some form of precipitation will be observed in a given day is 9%, with little variation over the course of the month.
Throughout September, the most common forms of precipitation are thunderstorms and light rain.
Thunderstorms are the most severe precipitation observed during 43% of those days with precipitation. They are most likely around September 5, when it is observed during 4% of all days.
Light rain is the most severe precipitation observed during 43% of those days with precipitation. It is most likely around September 5, when it is observed during 4% of all days.
Either snow is exceptionally unlikely to fall at this location in September or this station does not reliably report precipitation types.
The relative humidity typically ranges from 14% (very dry) to 38% (comfortable) over the course of a typical September, rarely dropping below 6% (very dry), or exceeding 59% (mildly humid).
The air is driest around September 9, at which time the relative humidity drops below 17% (dry) three days out of four; it is most humid around September 30, rising above 29% (dry) 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 September, the dew point typically varies from 28°F (dry) to 50°F (dry) and is rarely below 14°F (dry) or above 62°F (mildy humid).
Over the course of September typical wind speeds vary from 0 mph to 15 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 7 mph (light breeze) occurs around September 12, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around September 21, at which time the average daily maximum wind speed is 13 mph (moderate breeze).