This report describes the typical weather at the San Antonio International Airport (San Antonio, Texas, United States) weather station over the course of an average October. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
San Antonio, Texas has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by grasslands (56%), forests (20%), croplands (14%), and built-up areas (9%).
The month of October is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 86°F to 76°F over the course of the month, exceeding 92°F or dropping below 66°F only one day in ten.
Over the course of October, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 50 minutes, implying an average day-over-day decrease of 1.6 minutes.
The shortest day of the month is October 31 with 11:01 hours of daylight; the longest day is October 1 with 11:51 hours of daylight.
The earliest sunrise is at 7:28am on October 1; the latest sunset is at 7:19pm on October 1; the latest sunrise is at 7:47am on October 31; the earliest sunset is at 6:48pm on October 31.
Daylight savings time is observed in 2012 but it neither starts nor ends in October, so the entire month is in daylight time.
The median cloud cover ranges from 55% (partly cloudy) to 62% (partly cloudy). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 7% from the start to the end of the month.
On October 16, a representative day, the sky is clear or mostly clear 42% of the time, partly cloudy 16% of the time, and mostly cloudy or overcast 40% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around October 31, occurring in 32% of days. Precipitation is least likely around October 15, occurring in 28% of days.
Throughout October, the most common forms of precipitation are light rain, thunderstorms, and moderate rain.
Light rain is the most severe precipitation observed during 35% of those days with precipitation. It is most likely around October 31, when it is observed during 12% of all days.
Thunderstorms are the most severe precipitation observed during 29% of those days with precipitation. They are most likely around October 1, when it is observed during 11% of all days.
Moderate rain is the most severe precipitation observed during 22% of those days with precipitation. It is most likely around October 19, when it is observed during 7% of all days.
Either snow is exceptionally unlikely to fall at this location in October or this station does not reliably report precipitation types.
The relative humidity typically ranges from 42% (comfortable) to 90% (very humid) over the course of a typical October, rarely dropping below 24% (dry) and reaching as high as 100% (very humid).
The air is driest around October 1, at which time the relative humidity drops below 50% (mildly humid) three days out of four; it is most humid around October 31, rising above 87% (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 October, the dew point typically varies from 47°F (dry) to 65°F (mildy humid) and is rarely below 31°F (dry) or above 74°F (very muggy).
The time of the month between October 1 and October 31 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of October typical wind speeds vary from 1 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 October 30, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around October 5, at which time the average daily maximum wind speed is 13 mph (moderate breeze).