Average Weather in Jefferson Louisiana, United States
In Jefferson, the summers are long, hot, and oppressive; the winters are short, cool, and windy; and it is wet and partly cloudy year round. Over the course of the year, the temperature typically varies from 47°F to 92°F and is rarely below 34°F or above 97°F.
Based on the tourism score, the best times of year to visit Jefferson for warm-weather activities are from late March to mid May and from late September to early November.
The hot season lasts for 4.1 months, from May 19 to September 23, with an average daily high temperature above 86°F. The hottest day of the year is July 21, with an average high of 92°F and low of 78°F.
The cool season lasts for 2.9 months, from November 30 to February 24, with an average daily high temperature below 68°F. The coldest day of the year is January 8, with an average low of 47°F and high of 63°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, 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 Jefferson, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Jefferson begins around September 12 and lasts for 9.1 months, ending around June 17. On October 26, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 67% of the time, and overcast or mostly cloudy 33% of the time.
The cloudier part of the year begins around June 17 and lasts for 2.9 months, ending around September 12. On July 30, the cloudiest day of the year, the sky is overcast or mostly cloudy 59% of the time, and clear, mostly clear, or partly cloudy 41% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Jefferson varies significantly throughout the year.
The wetter season lasts 3.3 months, from June 2 to September 12, with a greater than 41% chance of a given day being a wet day. The chance of a wet day peaks at 61% on July 29.
The drier season lasts 8.7 months, from September 12 to June 2. The smallest chance of a wet day is 21% on October 29.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 61% on July 29.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Jefferson experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Jefferson. The most rain falls during the 31 days centered around June 28, with an average total accumulation of 5.6 inches.
The least rain falls around October 17, with an average total accumulation of 3.3 inches.
Average Monthly Rainfall
The length of the day in Jefferson varies significantly over the course of the year. In 2018, the shortest day is December 21, with 10 hours, 13 minutes of daylight; the longest day is June 21, with 14 hours, 5 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:58 AM on June 11, and the latest sunrise is 1 hour, 17 minutes later at 7:16 AM on November 3. The earliest sunset is at 5:00 PM on December 1, and the latest sunset is 3 hours, 5 minutes later at 8:05 PM on June 30.
Daylight saving time (DST) is observed in Jefferson during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
Jefferson experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 5.9 months, from April 24 to October 22, during which time the comfort level is muggy, oppressive, or miserable at least 28% of the time. The muggiest day of the year is July 23, with muggy conditions 99% of the time.
The least muggy day of the year is January 23, with muggy conditions 5% of the time.
Humidity Comfort Levels
The average hourly wind speed in Jefferson experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 8.0 months, from September 24 to May 23, with average wind speeds of more than 8.7 miles per hour. The windiest day of the year is March 7, with an average hourly wind speed of 10.7 miles per hour.
The calmer time of year lasts for 4.0 months, from May 23 to September 24. The calmest day of the year is August 8, with an average hourly wind speed of 6.8 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Jefferson varies throughout the year.
The wind is most often from the south for 4.7 months, from February 23 to July 15 and for 6.0 days, from August 16 to August 22, with a peak percentage of 50% on June 2. The wind is most often from the east for 2.9 months, from August 22 to November 19, with a peak percentage of 44% on September 20. The wind is most often from the north for 3.1 months, from November 19 to February 23, with a peak percentage of 37% on January 1.
Jefferson 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 water temperature experiences significant seasonal variation over the course of the year.
The time of year with warmer water lasts for 3.9 months, from May 28 to September 26, with an average temperature above 80°F. The day of the year with the warmest water is August 10, with an average temperature of 86°F.
The time of year with cooler water lasts for 3.4 months, from December 7 to March 20, with an average temperature below 65°F. The day of the year with the coolest water is February 1, with an average temperature of 60°F.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in Jefferson throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Jefferson for general outdoor tourist activities are from late March to mid May and from late September to early November, with a peak score in the last week of April.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best times of year to visit Jefferson for hot-weather activities are from early May to mid June and from early September to early October, with a peak score in the third week of May.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in Jefferson typically lasts for 12 months (353 days), from around January 17 to around January 4, rarely starting after February 22, or ending before December 11.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Jefferson should appear around January 15, only rarely appearing before January 9 or after January 25.
Growing Degree Days
The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.
The brighter period of the year lasts for 2.7 months, from April 1 to June 22, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is May 19, with an average of 6.6 kWh.
The darker period of the year lasts for 2.5 months, from November 16 to February 1, with an average daily incident shortwave energy per square meter below 3.7 kWh. The darkest day of the year is December 24, with an average of 3.0 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Jefferson are 29.966 deg latitude, -90.153 deg longitude, and 3 ft elevation.
The topography within 2 miles of Jefferson is essentially flat, with a maximum elevation change of 43 feet and an average elevation above sea level of 5 feet. Within 10 miles is also essentially flat (49 feet). Within 50 miles is essentially flat (827 feet).
The area within 2 miles of Jefferson is covered by artificial surfaces (71%), water (12%), and herbaceous vegetation (12%), within 10 miles by artificial surfaces (42%) and herbaceous vegetation (28%), and within 50 miles by herbaceous vegetation (55%) and water (28%).
This report illustrates the typical weather in Jefferson, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Jefferson.
For each station, the records are corrected for the elevation difference between that station and Jefferson 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 Jefferson is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Jefferson and a given station.
Time zones for aiports and weather stations are provided by AskGeo.com .