Average Weather in September in San Fernando Mexico
Daily high temperatures are around 83°F, rarely falling below 76°F or exceeding 89°F.
Daily low temperatures are around 68°F, rarely falling below 65°F or exceeding 71°F. The highest daily average low temperature is 68°F on September 12.
For reference, on May 3, the hottest day of the year, temperatures in San Fernando typically range from 68°F to 89°F, while on January 18, the coldest day of the year, they range from 59°F to 78°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
Santa Cruz de la Sierra, Bolivia (3,151 miles away); Badulla, Sri Lanka (10,754 miles); and Lagawe, Philippines (9,149 miles) are the far-away foreign places with temperatures most similar to San Fernando (view comparison).
The month of September in San Fernando experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 90% throughout the month. The highest chance of overcast or mostly cloudy conditions is 92% on September 15.
The clearest day of the month is September 30, with clear, mostly clear, or partly cloudy conditions 12% of the time.
For reference, on June 24, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 92%, while on February 14, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 73%.
Cloud Cover Categories in September
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Fernando, the chance of a wet day over the course of September is rapidly decreasing, starting the month at 85% and ending it at 77%.
For reference, the year's highest daily chance of a wet day is 87% on September 11, and its lowest chance is 14% on March 24.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in San Fernando is gradually decreasing, starting the month at 10.0 inches, when it rarely exceeds 15.0 inches or falls below 6.6 inches, and ending the month at 9.6 inches, when it rarely exceeds 14.2 inches or falls below 5.5 inches.
The highest average 31-day accumulation is 10.6 inches on September 15.
Average Monthly Rainfall in September
Over the course of September in San Fernando, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 27 minutes, implying an average daily decrease of 56 seconds, and weekly decrease of 6 minutes, 33 seconds.
The shortest day of the month is September 30, with 11 hours, 60 minutes of daylight and the longest day is September 1, with 12 hours, 27 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in San Fernando is 6:59 AM on September 1 and the latest sunrise is 4 minutes later at 7:02 AM on September 30.
The latest sunset is 7:25 PM on September 1 and the earliest sunset is 24 minutes earlier at 7:02 PM on September 30.
Daylight saving time is observed in San Fernando 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 6:40 AM and sets 13 hours, 8 minutes later, at 7:48 PM, while on December 21, the shortest day of the year, it rises at 6:37 AM and sets 11 hours, 7 minutes later, at 5:44 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in September
The chance that a given day will be muggy in San Fernando is decreasing during September, falling from 94% to 87% over the course of the month.
The highest chance of a muggy day during September is 94% on September 12.
For reference, on September 12, the muggiest day of the year, there are muggy conditions 94% of the time, while on January 18, the least muggy day of the year, there are muggy conditions 7% of the time.
Humidity Comfort Levels in September
The average hourly wind speed in San Fernando is increasing during September, increasing from 4.8 miles per hour to 5.9 miles per hour over the course of the month.
For reference, on January 29, the windiest day of the year, the daily average wind speed is 8.0 miles per hour, while on June 21, the calmest day of the year, the daily average wind speed is 4.4 miles per hour.
Average Wind Speed in September
Wind Direction in September
San Fernando is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in San Fernando is essentially constant during September, remaining within 1°F of 86°F throughout.
Average Water Temperature in September
Temperatures in San Fernando are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season in September
The average accumulated growing degree days in San Fernando are rapidly increasing during September, increasing by 716°F, from 5,832°F to 6,548°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in San Fernando is essentially constant during September, remaining within 0.1 kWh of 4.8 kWh throughout.
The lowest average daily incident shortwave solar energy during September is 4.7 kWh on September 15.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of San Fernando are 16.872 deg latitude, -93.208 deg longitude, and 3,245 ft elevation.
The topography within 2 miles of San Fernando contains very significant variations in elevation, with a maximum elevation change of 1,178 feet and an average elevation above sea level of 3,171 feet. Within 10 miles contains very significant variations in elevation (5,164 feet). Within 50 miles also contains extreme variations in elevation (9,429 feet).
The area within 2 miles of San Fernando is covered by cropland (89%) and trees (11%), within 10 miles by cropland (75%) and trees (18%), and within 50 miles by cropland (65%) and trees (29%).
This report illustrates the typical weather in San Fernando 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 San Fernando.
For each station, the records are corrected for the elevation difference between that station and San Fernando 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 San Fernando is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between San Fernando and a given station.
The stations contributing to this reconstruction are: General Div P A Angel H Corzo Molina (22%, 15 kilometers, south); Ángel Albino Corzo International Airport (75%, 18 kilometers, southwest); and Carlos Rovirosa Pérez International Airport (3.0%, 130 kilometers, north).
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 .