Average Weather in September in Shell Valley North Dakota, United States
Daily high temperatures decrease by 13°F, from 73°F to 60°F, rarely falling below 46°F or exceeding 84°F.
Daily low temperatures decrease by 12°F, from 50°F to 38°F, rarely falling below 28°F or exceeding 59°F.
For reference, on July 24, the hottest day of the year, temperatures in Shell Valley typically range from 56°F to 77°F, while on January 12, the coldest day of the year, they range from -1°F to 15°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 Shell Valley experiences increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 35% to 43%.
The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 65% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 66%, while on July 31, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 73%.
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 Shell Valley, the chance of a wet day over the course of September is decreasing, starting the month at 22% and ending it at 16%.
For reference, the year's highest daily chance of a wet day is 37% on June 14, and its lowest chance is 4% on February 8.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Shell Valley is gradually decreasing, starting the month at 1.6 inches, when it rarely exceeds 3.1 inches or falls below 0.5 inches, and ending the month at 1.2 inches, when it rarely exceeds 2.6 inches or falls below 0.2 inches.
Average Monthly Rainfall in September
Over the course of September in Shell Valley, 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, 42 minutes, implying an average daily decrease of 3 minutes, 32 seconds, and weekly decrease of 24 minutes, 43 seconds.
The shortest day of the month is September 30, with 11 hours, 42 minutes of daylight and the longest day is September 1, with 13 hours, 24 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Shell Valley is 6:56 AM on September 1 and the latest sunrise is 41 minutes later at 7:38 AM on September 30.
The latest sunset is 8:20 PM on September 1 and the earliest sunset is 1 hour, 1 minute earlier at 7:19 PM on September 30.
Daylight saving time is observed in Shell Valley 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 5:36 AM and sets 16 hours, 10 minutes later, at 9:46 PM, while on December 21, the shortest day of the year, it rises at 8:30 AM and sets 8 hours, 15 minutes later, at 4:45 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 Shell Valley is gradually decreasing during September, falling from 4% to 0% over the course of the month.
For reference, on July 17, the muggiest day of the year, there are muggy conditions 16% of the time, while on October 12, 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 Shell Valley is increasing during September, increasing from 9.2 miles per hour to 10.4 miles per hour over the course of the month.
For reference, on March 31, the windiest day of the year, the daily average wind speed is 11.9 miles per hour, while on July 22, the calmest day of the year, the daily average wind speed is 8.3 miles per hour.
Average Wind Speed in September
The wind direction in Shell Valley during September is predominantly out of the south from September 1 to September 4 and the west from September 4 to September 30.
Wind Direction in September
The growing season in Shell Valley typically lasts for 4.2 months (129 days), from around May 17 to around September 23, rarely starting before April 30 or after June 2, and rarely ending before September 7 or after October 8.
During September in Shell Valley, the chance that a given day is within the growing season is very rapidly decreasing falling from 96% to 27% 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 Shell Valley are increasing during September, increasing by 207°F, from 1,516°F to 1,724°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Shell Valley is rapidly decreasing during September, falling by 1.5 kWh, from 5.2 kWh to 3.7 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 Shell Valley are 48.798 deg latitude, -99.865 deg longitude, and 1,772 ft elevation.
The topography within 2 miles of Shell Valley contains only modest variations in elevation, with a maximum elevation change of 276 feet and an average elevation above sea level of 1,775 feet. Within 10 miles contains only modest variations in elevation (712 feet). Within 50 miles contains significant variations in elevation (1,286 feet).
The area within 2 miles of Shell Valley is covered by cropland (76%) and grassland (20%), within 10 miles by cropland (48%) and trees (28%), and within 50 miles by cropland (72%) and grassland (15%).
This report illustrates the typical weather in Shell Valley, 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Shell Valley.
For each station, the records are corrected for the elevation difference between that station and Shell Valley 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 Shell Valley is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Shell Valley and a given station.
The stations contributing to this reconstruction are: Rugby Municipal Airport (73%, 20 kilometers, northeast); Rugby Municipal Airport (20%, 47 kilometers, south); and Melita, Man (7%, 98 kilometers, northwest).
Time zones for airports and weather stations are provided by AskGeo.com .