This report describes the typical weather at the Syracuse Hancock International Airport (Syracuse, New York, United States) weather station over the course of an average September. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Syracuse, New York has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by forests (90%), lakes and rivers (6%), and built-up areas (3%).
The month of September is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 76°F to 66°F over the course of the month, exceeding 85°F or dropping below 55°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 1:23 hours, implying an average day-over-day decrease of 2.8 minutes.
The shortest day of the month is September 30 with 11:46 hours of daylight; the longest day is September 1 with 13:09 hours of daylight.
The earliest sunrise is at 6:29am on September 1; the latest sunset is at 7:38pm on September 1; the latest sunrise is at 7:01am on September 30; the earliest sunset is at 6:47pm 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 ranges from 75% (partly cloudy) to 83% (mostly cloudy). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 8% from the start to the end of the month.
On September 15, a representative day, the sky is clear or mostly clear 28% of the time, partly cloudy 19% of the time, and mostly cloudy or overcast 51% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around September 28, occurring in 54% of days. Precipitation is least likely around September 1, occurring in 47% of days.
Throughout September, the most common forms of precipitation are light rain, moderate rain, and thunderstorms.
Light rain is the most severe precipitation observed during 42% of those days with precipitation. It is most likely around September 29, when it is observed during 24% of all days.
Moderate rain is the most severe precipitation observed during 31% of those days with precipitation. It is most likely around September 27, when it is observed during 17% of all days.
Thunderstorms are the most severe precipitation observed during 15% of those days with precipitation. They are most likely around September 1, when it is observed during 10% of all days.
The likelihood of snow falling is highest around September 30, occurring in 2% of days.
Either snow rarely accumulates at this location in September or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 53% (mildly humid) to 94% (very humid) over the course of a typical September, rarely dropping below 39% (comfortable) and reaching as high as 100% (very humid).
The air is driest around September 1, at which time the relative humidity drops below 61% (mildly humid) three days out of four; it is most humid around September 9, rising above 91% (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 September, the dew point typically varies from 43°F (dry) to 62°F (mildy humid) and is rarely below 33°F (dry) or above 70°F (muggy).
The time of the month between September 1 and September 30 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of September typical wind speeds vary from 0 mph to 14 mph (calm to moderate breeze), rarely exceeding 20 mph (fresh breeze).
The highest average wind speed of 8 mph (gentle breeze) occurs around September 29, 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 1, at which time the average daily maximum wind speed is 13 mph (moderate breeze).