Average Weather in September in Bellevue Idaho, United States
Daily high temperatures decrease by 12°F, from 77°F to 65°F, rarely falling below 52°F or exceeding 85°F.
Daily low temperatures decrease by 9°F, from 47°F to 38°F, rarely falling below 29°F or exceeding 55°F.
For reference, on July 26, the hottest day of the year, temperatures in Bellevue typically range from 53°F to 84°F, while on January 2, the coldest day of the year, they range from 13°F to 30°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 Bellevue experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 25% to 33%.
The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 75% of the time.
For reference, on February 27, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on July 27, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 82%.
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 Bellevue, the chance of a wet day over the course of September is essentially constant, remaining around 10% throughout.
For reference, the year's highest daily chance of a wet day is 21% on May 23, and its lowest chance is 6% on July 6.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Bellevue is essentially constant, remaining about 0.6 inches throughout, and rarely exceeding 1.6 inches.
Average Monthly Rainfall in September
Over the course of September in Bellevue, 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, 25 minutes, implying an average daily decrease of 2 minutes, 56 seconds, and weekly decrease of 20 minutes, 29 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, 10 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Bellevue is 7:01 AM on September 1 and the latest sunrise is 32 minutes later at 7:34 AM on September 30.
The latest sunset is 8:11 PM on September 1 and the earliest sunset is 52 minutes earlier at 7:18 PM on September 30.
Daylight saving time is observed in Bellevue during 2020, but it neither starts nor ends during September, so the entire month is in daylight saving time.
For reference, on June 20, the longest day of the year, the Sun rises at 5:56 AM and sets 15 hours, 25 minutes later, at 9:21 PM, while on December 21, the shortest day of the year, it rises at 8:06 AM and sets 8 hours, 57 minutes later, at 5:04 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Bellevue is essentially constant during September, remaining around 0% throughout.
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 Bellevue is essentially constant during September, remaining within 0.2 miles per hour of 7.2 miles per hour throughout.
For reference, on June 25, the windiest day of the year, the daily average wind speed is 8.0 miles per hour, while on December 25, the calmest day of the year, the daily average wind speed is 6.1 miles per hour.
Average Wind Speed in September
The hourly average wind direction in Bellevue throughout September is predominantly from the west, with a peak proportion of 35% on September 3.
Wind Direction in September
The growing season in Bellevue typically lasts for 3.9 months (119 days), from around May 29 to around September 25, rarely starting before May 4 or after June 19, and rarely ending before September 7 or after October 16.
During September in Bellevue, the chance that a given day is within the growing season is very rapidly decreasing falling from 96% to 37% 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 Bellevue are increasing during September, increasing by 244°F, from 1,595°F to 1,839°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Bellevue is rapidly decreasing during September, falling by 1.6 kWh, from 6.3 kWh to 4.7 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 Bellevue are 43.464 deg latitude, -114.261 deg longitude, and 5,509 ft elevation.
The topography within 2 miles of Bellevue contains very significant variations in elevation, with a maximum elevation change of 1,946 feet and an average elevation above sea level of 5,426 feet. Within 10 miles contains very significant variations in elevation (3,694 feet). Within 50 miles also contains extreme variations in elevation (8,967 feet).
The area within 2 miles of Bellevue is covered by shrubs (61%) and cropland (21%), within 10 miles by shrubs (73%) and cropland (14%), and within 50 miles by shrubs (64%).
This report illustrates the typical weather in Bellevue 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Bellevue.
For each station, the records are corrected for the elevation difference between that station and Bellevue 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 Bellevue is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Bellevue and a given station.
The stations contributing to this reconstruction are: Friedman Memorial Airport (96%, 5.2 kilometers, northwest); Jerome County Airport (2.4%, 84 kilometers, south); and Pocatello Regional Airport (1.2%, 150 kilometers, southeast).
Time zones for aiports and weather stations are provided by AskGeo.com .