Average Weather in September in Mont-de-Lans France
Daily high temperatures decrease by 8°F, from 61°F to 54°F, rarely falling below 45°F or exceeding 70°F.
Daily low temperatures decrease by 6°F, from 43°F to 37°F, rarely falling below 31°F or exceeding 48°F.
For reference, on August 4, the hottest day of the year, temperatures in Mont-de-Lans typically range from 46°F to 65°F, while on January 18, the coldest day of the year, they range from 14°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
Girdwood, Alaska, United States (4,990 miles away) and Breckenridge, Colorado, United States (5,248 miles) are the far-away foreign places with temperatures most similar to Mont-de-Lans (view comparison).
The month of September in Mont-de-Lans experiences rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 41% to 53%.
The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 59% of the time.
For reference, on May 9, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 60%, while on July 21, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 67%.
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 Mont-de-Lans, the chance of a wet day over the course of September is gradually increasing, starting the month at 22% and ending it at 26%.
For reference, the year's highest daily chance of a wet day is 32% on May 25, and its lowest chance is 19% on March 5.
Over the course of September in Mont-de-Lans, the chance of a day with only rain increases from 22% to 25%, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 0% throughout.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Mont-de-Lans is increasing, starting the month at 2.0 inches, when it rarely exceeds 3.4 inches or falls below 0.7 inches, and ending the month at 2.5 inches, when it rarely exceeds 4.8 inches or falls below 0.6 inches.
Average Monthly Rainfall in September
Over the course of September in Mont-de-Lans, 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, 30 minutes, implying an average daily decrease of 3 minutes, 5 seconds, and weekly decrease of 21 minutes, 38 seconds.
The shortest day of the month is September 30, with 11 hours, 46 minutes of daylight and the longest day is September 1, with 13 hours, 16 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Mont-de-Lans is 6:57 AM on September 1 and the latest sunrise is 35 minutes later at 7:31 AM on September 30.
The latest sunset is 8:12 PM on September 1 and the earliest sunset is 55 minutes earlier at 7:18 PM on September 30.
Daylight saving time is observed in Mont-de-Lans 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 5:48 AM and sets 15 hours, 37 minutes later, at 9:25 PM, while on December 21, the shortest day of the year, it rises at 8:10 AM and sets 8 hours, 46 minutes later, at 4:56 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in September
The chance that a given day will be muggy in Mont-de-Lans 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 Mont-de-Lans is essentially constant during September, remaining around 4.7 miles per hour throughout.
For reference, on April 15, the windiest day of the year, the daily average wind speed is 5.3 miles per hour, while on August 11, the calmest day of the year, the daily average wind speed is 4.5 miles per hour.
Average Wind Speed in September
Wind Direction in September
The growing season in Mont-de-Lans typically lasts for 3.9 months (119 days), from around May 29 to around September 24, rarely starting before May 7 or after June 22, and rarely ending before August 29 or after October 17.
During September in Mont-de-Lans, the chance that a given day is within the growing season is rapidly decreasing falling from 87% to 38% 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 Mont-de-Lans are gradually increasing during September, increasing by 78°F, from 571°F to 649°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Mont-de-Lans is rapidly decreasing during September, falling by 1.6 kWh, from 5.7 kWh to 4.1 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 Mont-de-Lans are 45.036 deg latitude, 6.131 deg longitude, and 5,407 ft elevation.
The topography within 2 miles of Mont-de-Lans contains extreme variations in elevation, with a maximum elevation change of 4,623 feet and an average elevation above sea level of 4,744 feet. Within 10 miles also contains extreme variations in elevation (10,620 feet). Within 50 miles also contains extreme variations in elevation (12,759 feet).
The area within 2 miles of Mont-de-Lans is covered by trees (35%), grassland (30%), and sparse vegetation (12%), within 10 miles by grassland (29%) and bare soil (23%), and within 50 miles by trees (42%) and grassland (21%).
This report illustrates the typical weather in Mont-de-Lans 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 7 weather stations near enough to contribute to our estimation of the temperature and dew point in Mont-de-Lans.
For each station, the records are corrected for the elevation difference between that station and Mont-de-Lans 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 Mont-de-Lans is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Mont-de-Lans and a given station.
The stations contributing to this reconstruction are: Chambéry Airport (16%, 70 kilometers, north); Grenoble-Isère Airport (18%, 73 kilometers, northwest); Château-Arnoux-Saint-Auban Airport (15%, 108 kilometers, south); Turin Caselle Airport (13%, 121 kilometers, east); Montélimar-Ancône (11%, 121 kilometers, southwest); Aosta Airport (15%, 123 kilometers, northeast); and Cuneo International Airport (13%, 130 kilometers, southeast).
Time zones for aiports and weather stations are provided by AskGeo.com .