This report describes the typical weather at the Stillwater (Stillwater, Oklahoma, United States) weather station over the course of an average year. It is based on the historical records from 1997 to 2012. Earlier records are either unavailable or unreliable.
Stillwater, Oklahoma 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 (87%) and croplands (10%).
Over the course of a year, the temperature typically varies from 27Â°F to 96Â°F and is rarely below 15Â°F or above 104Â°F.
The warm season lasts from June 8 to September 12 with an average daily high temperature above 86Â°F. The hottest day of the year is July 26, with an average high of 96Â°F and low of 72Â°F.
The cold season lasts from November 24 to February 27 with an average daily high temperature below 58Â°F. The coldest day of the year is January 16, with an average low of 27Â°F and high of 49Â°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 9:42 hours of daylight; the longest day is June 20 with 14:38 hours of daylight.
The earliest sunrise is at 6:10am on June 15 and the latest sunset is at 8:50pm on July 2. The latest sunrise is at 7:54am on November 3 and the earliest sunset is at 5:13pm on December 8.
Daylight saving time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.
The median cloud cover ranges from 1% (clear) to 16% (mostly clear). The sky is cloudiest on February 28 and clearest on July 22. The clearer part of the year begins around May 9. The cloudier part of the year begins around January 22.
On July 22, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 86% of the time, and overcast or mostly cloudy 11% of the time.
On February 28, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 37% of the time, and clear or mostly clear 62% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around May 22, occurring in 40% of days. Precipitation is least likely around January 15, occurring in 23% of days.
Over the entire year, the most common forms of precipitation are thunderstorms, light rain, moderate rain, and heavy rain.
Thunderstorms are the most severe precipitation observed during 34% of those days with precipitation. They are most likely around June 5, when it is observed during 21% of all days.
Light rain is the most severe precipitation observed during 31% of those days with precipitation. It is most likely around April 6, when it is observed during 13% of all days.
Moderate rain is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around April 16, when it is observed during 6% of all days.
Heavy rain is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around September 30, when it is observed during 5% of all days.
During the warm season, which lasts from June 8 to September 12, there is a 31% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of thunderstorms (53% of days with precipitation have at worst thunderstorms), light rain (23%), heavy rain (14%), and moderate rain (10%).
During the cold season, which lasts from November 24 to February 27, there is a 25% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (35% of days with precipitation have at worst light rain), light snow (23%), moderate rain (14%), and thunderstorms (11%).
The likelihood of snow falling is highest around January 19, occurring in 11% of days. The season in which it is relatively likely for snow to fall spans from November 13 to March 16.
Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 38% (comfortable) to 91% (very humid) over the course of the year, rarely dropping below 21% (dry) and reaching as high as 100% (very humid).
The air is driest around March 5, at which time the relative humidity drops below 47% (comfortable) three days out of four; it is most humid around October 16, exceeding 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 year, the dew point typically varies from 19Â°F (dry) to 72Â°F (very muggy) and is rarely below 7Â°F (dry) or above 76Â°F (very muggy).
There are two periods in the year that are most comfortable: The first is between April 11 and May 27 and the second is between September 9 and October 26. The air feels neither too dry nor too muggy during these periods.
Over the course of the year typical wind speeds vary from 0 mph to 21 mph (calm to fresh breeze), rarely exceeding 28 mph (strong breeze).
The highest average wind speed of 12 mph (gentle breeze) occurs around April 6, at which time the average daily maximum wind speed is 21 mph (fresh breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around August 7, at which time the average daily maximum wind speed is 14 mph (moderate breeze).