Average Weather in September in Sac City Iowa, United States
Daily high temperatures decrease by 9°F, from 79°F to 70°F, rarely falling below 58°F or exceeding 89°F.
Daily low temperatures decrease by 12°F, from 60°F to 48°F, rarely falling below 36°F or exceeding 69°F.
For reference, on July 5, the hottest day of the year, temperatures in Sac City typically range from 65°F to 84°F, while on January 20, the coldest day of the year, they range from 13°F to 29°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
Almaty, Kazakhstan (6,503 miles away); Yinchuan, China (6,698 miles); and Kujang-ŭp, North Korea (6,206 miles) are the far-away foreign places with temperatures most similar to Sac City (view comparison).
The month of September in Sac City experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 32% throughout the month.
The clearest day of the month is September 14, with clear, mostly clear, or partly cloudy conditions 70% of the time.
For reference, on February 3, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on July 28, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 72%.
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 Sac City, the chance of a wet day over the course of September is decreasing, starting the month at 31% and ending it at 27%.
For reference, the year's highest daily chance of a wet day is 43% on June 7, and its lowest chance is 8% on January 11.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Sac City is decreasing, starting the month at 3.2 inches, when it rarely exceeds 5.5 inches or falls below 1.2 inches, and ending the month at 2.5 inches, when it rarely exceeds 4.3 inches or falls below 0.9 inches.
Average Monthly Rainfall in September
Over the course of September in Sac City, 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, 22 minutes, implying an average daily decrease of 2 minutes, 49 seconds, and weekly decrease of 19 minutes, 44 seconds.
The shortest day of the month is September 30, with 11 hours, 47 minutes of daylight and the longest day is September 1, with 13 hours, 9 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Sac City is 6:45 AM on September 1 and the latest sunrise is 31 minutes later at 7:16 AM on September 30.
The latest sunset is 7:53 PM on September 1 and the earliest sunset is 51 minutes earlier at 7:03 PM on September 30.
Daylight saving time is observed in Sac City during 2018, 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 5:42 AM and sets 15 hours, 18 minutes later, at 9:00 PM, while on December 21, the shortest day of the year, it rises at 7:46 AM and sets 9 hours, 4 minutes later, at 4:50 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Sac City is very rapidly decreasing during September, falling from 29% to 3% over the course of the month.
For reference, on July 22, the muggiest day of the year, there are muggy conditions 51% of the time, while on November 15, 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 Sac City is increasing during September, increasing from 9.5 miles per hour to 11.0 miles per hour over the course of the month.
For reference, on April 12, the windiest day of the year, the daily average wind speed is 13.4 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 8.5 miles per hour.
Average Wind Speed in September
Wind Direction in September
The growing season in Sac City typically lasts for 5.6 months (171 days), from around April 22 to around October 10, rarely starting before April 3 or after May 13, and rarely ending before September 23 or after October 29.
The month of September in Sac City is more likely than not fully within the growing season, with the chance that a given day is in the growing season rapidly decreasing from 100% to 76% 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 Sac City are increasing during September, increasing by 414°F, from 2,588°F to 3,002°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Sac City is decreasing during September, falling by 1.2 kWh, from 5.6 kWh to 4.4 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 Sac City are 42.422 deg latitude, -94.990 deg longitude, and 1,243 ft elevation.
The topography within 2 miles of Sac City contains only modest variations in elevation, with a maximum elevation change of 128 feet and an average elevation above sea level of 1,239 feet. Within 10 miles also contains only modest variations in elevation (312 feet). Within 50 miles contains only modest variations in elevation (636 feet).
The area within 2 miles of Sac City is covered by cropland (91%), within 10 miles by cropland (99%), and within 50 miles by cropland (98%).
This report illustrates the typical weather in Sac City year round, 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 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Sac City.
For each station, the records are corrected for the elevation difference between that station and Sac City 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 Sac City is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Sac City and a given station.
The stations contributing to this reconstruction are: Storm Lake Municipal Airport (46%, 28 kilometers, northwest); Arthur N Neu Airport (24%, 45 kilometers, south); Denison Municipal Airport (16%, 58 kilometers, southwest); and Fort Dodge Municipal Airport (13%, 68 kilometers, east).
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Time zones for aiports and weather stations are provided by AskGeo.com .