Average Weather in September in Stonington Maine, United States
Daily high temperatures decrease by 8°F, from 69°F to 60°F, rarely falling below 54°F or exceeding 76°F.
Daily low temperatures decrease by 8°F, from 55°F to 48°F, rarely falling below 39°F or exceeding 62°F.
For reference, on July 26, the hottest day of the year, temperatures in Stonington typically range from 59°F to 72°F, while on January 29, the coldest day of the year, they range from 17°F to 32°F.
Average High and Low Temperature in September
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in September
The month of September in Stonington experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 39% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 37% on September 3.
The clearest day of the month is September 3, with clear, mostly clear, or partly cloudy conditions 63% of the time.
For reference, on May 16, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 58%, while on September 3, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 63%.
Cloud Cover Categories in September
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Stonington, the chance of a wet day over the course of September is increasing, starting the month at 22% and ending it at 27%.
For reference, the year's highest daily chance of a wet day is 33% on December 11, and its lowest chance is 22% on August 30.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Stonington is rapidly increasing, starting the month at 2.8 inches, when it rarely exceeds 5.4 inches or falls below 1.1 inches, and ending the month at 3.9 inches, when it rarely exceeds 7.0 inches or falls below 1.5 inches.
Average Monthly Rainfall in September
Over the course of September in Stonington, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 27 minutes, implying an average daily decrease of 3 minutes, 0 seconds, and weekly decrease of 20 minutes, 59 seconds.
The shortest day of the month is September 30, with 11 hours, 45 minutes of daylight and the longest day is September 1, with 13 hours, 12 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Stonington is 5:58 AM on September 1 and the latest sunrise is 33 minutes later at 6:31 AM on September 30.
The latest sunset is 7:10 PM on September 1 and the earliest sunset is 53 minutes earlier at 6:16 PM on September 30.
Daylight saving time is observed in Stonington during 2021, but it neither starts nor ends during September, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 4:51 AM and sets 15 hours, 30 minutes later, at 8:21 PM, while on December 21, the shortest day of the year, it rises at 7:06 AM and sets 8 hours, 52 minutes later, at 3:59 PM.
Sunrise & Sunset with Twilight in September
The figure below presents a compact representation of key lunar data for September 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
Moon Rise, Set & Phases in September
The chance that a given day will be muggy in Stonington is gradually decreasing during September, falling from 4% to 0% over the course of the month.
For reference, on August 3, the muggiest day of the year, there are muggy conditions 9% of the time, while on October 30, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in September
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed in Stonington is increasing during September, increasing from 7.6 miles per hour to 9.4 miles per hour over the course of the month.
For reference, on January 13, the windiest day of the year, the daily average wind speed is 13.6 miles per hour, while on August 8, the calmest day of the year, the daily average wind speed is 6.9 miles per hour.
Average Wind Speed in September
The hourly average wind direction in Stonington throughout September is predominantly from the south, with a peak proportion of 36% on September 1.
Wind Direction in September
Stonington is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in Stonington is gradually decreasing during September, falling by 3°F, from 57°F to 54°F, over the course of the month.
Average Water Temperature in September
The growing season in Stonington typically lasts for 6.0 months (182 days), from around April 25 to around October 24, rarely starting before April 8 or after May 10, and rarely ending before October 5 or after November 11.
The month of September in Stonington is very likely fully within the growing season, with the chance that a given day is in the growing season gradually decreasing from 100% to 95% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in September
The average accumulated growing degree days in Stonington are increasing during September, increasing by 255°F, from 1,248°F to 1,503°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Stonington is decreasing during September, falling by 1.5 kWh, from 5.4 kWh to 4.0 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of Stonington are 44.156 deg latitude, -68.667 deg longitude, and 56 ft elevation.
The topography within 2 miles of Stonington contains only modest variations in elevation, with a maximum elevation change of 151 feet and an average elevation above sea level of 25 feet. Within 10 miles contains only modest variations in elevation (518 feet). Within 50 miles contains significant variations in elevation (1,532 feet).
The area within 2 miles of Stonington is covered by water (60%) and trees (25%), within 10 miles by water (81%) and trees (15%), and within 50 miles by water (61%) and trees (35%).
This report illustrates the typical weather in Stonington, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Stonington.
For each station, the records are corrected for the elevation difference between that station and Stonington according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Stonington is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Stonington and a given station.
Time zones for airports and weather stations are provided by AskGeo.com .