Average Weather in September in La Mesa Mexico
Daily high temperatures decrease by 3°F, from 89°F to 86°F, rarely falling below 78°F or exceeding 95°F.
Daily low temperatures decrease by 7°F, from 63°F to 56°F, rarely falling below 49°F or exceeding 68°F.
For reference, on June 19, the hottest day of the year, temperatures in La Mesa typically range from 63°F to 95°F, while on January 5, the coldest day of the year, they range from 35°F to 64°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
San Juan, Argentina (5,152 miles away); Gharyan, Libya (6,740 miles); and Narromine, Australia (7,906 miles) are the far-away foreign places with temperatures most similar to La Mesa (view comparison).
The month of September in La Mesa experiences very rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 33% to 17%. The lowest chance of overcast or mostly cloudy conditions is 17% on September 28.
The clearest day of the month is September 28, with clear, mostly clear, or partly cloudy conditions 83% of the time.
For reference, on July 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 52%, while on June 9, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 85%.
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 La Mesa, the chance of a wet day over the course of September is very rapidly decreasing, starting the month at 36% and ending it at 12%.
For reference, the year's highest daily chance of a wet day is 50% on August 4, and its lowest chance is 2% on May 23.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in La Mesa is rapidly decreasing, starting the month at 2.2 inches, when it rarely exceeds 3.3 inches or falls below 1.1 inches, and ending the month at 1.2 inches, when it rarely exceeds 2.5 inches or falls below 0.2 inches.
Average Monthly Rainfall in September
Over the course of September in La Mesa, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 54 minutes, implying an average daily decrease of 1 minute, 52 seconds, and weekly decrease of 13 minutes, 4 seconds.
The shortest day of the month is September 30, with 11 hours, 53 minutes of daylight and the longest day is September 1, with 12 hours, 47 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in La Mesa is 5:59 AM on September 1 and the latest sunrise is 17 minutes later at 6:17 AM on September 30.
The latest sunset is 6:47 PM on September 1 and the earliest sunset is 37 minutes earlier at 6:10 PM on September 30.
Daylight saving time is not observed in La Mesa during 2018.
For reference, on June 21, the longest day of the year, the Sun rises at 5:20 AM and sets 14 hours, 11 minutes later, at 7:31 PM, while on December 21, the shortest day of the year, it rises at 7:18 AM and sets 10 hours, 7 minutes later, at 5:25 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in La Mesa is rapidly decreasing during September, falling from 14% to 1% over the course of the month.
For reference, on August 6, the muggiest day of the year, there are muggy conditions 23% of the time, while on January 1, 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 La Mesa is increasing during September, increasing from 6.0 miles per hour to 7.3 miles per hour over the course of the month.
For reference, on April 30, the windiest day of the year, the daily average wind speed is 9.4 miles per hour, while on August 8, the calmest day of the year, the daily average wind speed is 5.5 miles per hour.
Average Wind Speed in September
Wind Direction in September
The growing season in La Mesa typically lasts for 8.0 months (243 days), from around March 18 to around November 16, rarely starting before February 19 or after April 19, and rarely ending before October 28 or after December 8.
The month of September in La Mesa is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in September
The average accumulated growing degree days in La Mesa are rapidly increasing during September, increasing by 655°F, from 3,946°F to 4,601°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in La Mesa is essentially constant during September, remaining within 0.1 kWh of 6.0 kWh throughout.
The highest average daily incident shortwave solar energy during September is 6.1 kWh on September 11.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of La Mesa are 31.160 deg latitude, -110.974 deg longitude, and 4,019 ft elevation.
The topography within 2 miles of La Mesa contains significant variations in elevation, with a maximum elevation change of 541 feet and an average elevation above sea level of 3,960 feet. Within 10 miles contains significant variations in elevation (3,366 feet). Within 50 miles also contains extreme variations in elevation (7,766 feet).
The area within 2 miles of La Mesa is covered by shrubs (83%) and grassland (17%), within 10 miles by shrubs (80%) and grassland (11%), and within 50 miles by shrubs (74%) and grassland (19%).
This report illustrates the typical weather in La Mesa 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 is only a single weather station, Nogales International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of La Mesa.
At a distance of 32 kilometers from La Mesa, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.
The station records are corrected for the elevation difference between the station and La Mesa according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.
Time zones for aiports and weather stations are provided by AskGeo.com .