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Average Weather at Harry P Williams Memorial Airport Louisiana, United States

At Harry P Williams Memorial Airport, 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 45°F to 90°F and is rarely below 31°F or above 94°F.

Based on the tourism score, the best times of year to visit Harry P Williams Memorial Airport for warm-weather activities are from late March to mid May and from late September to late October.

Climate Summary

coolcomfortablewarmhotwarmJanFebMarAprMayJunJulAugSepOctNovDecNowNow67%67%41%41%clearovercastprecipitation: 5.9 inprecipitation: 5.9 in3.7 in3.7 inmuggy: 98%muggy: 98%4%4%drydrytourism score: 6.6tourism score: 6.63.13.1
Click on each chart for more information.

Temperature

The hot season lasts for 4.2 months, from May 18 to September 26, with an average daily high temperature above 84°F. The hottest day of the year is July 25, with an average high of 90°F and low of 74°F.

The cool season lasts for 2.8 months, from December 1 to February 25, with an average daily high temperature below 68°F. The coldest day of the year is January 16, with an average low of 45°F and high of 63°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

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

Average Hourly Temperature at Harry P Williams Memorial AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMNowNowcoldcoldcoldcoldcoolcoolcomfortablewarmhotcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

El Hamma, Tunisia (5,680 miles away); Al Mindak, Saudi Arabia (7,775 miles); and Longmen, China (8,194 miles) are the far-away foreign places with temperatures most similar to Harry P Williams Memorial Airport (view comparison).

Clouds

At Harry P Williams Memorial Airport, 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 at Harry P Williams Memorial Airport begins around September 13 and lasts for 9.1 months, ending around June 17. On October 25, 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 13. On July 29, 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

Cloud Cover Categories at Harry P Williams Memorial AirportclearerclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Oct 2567%Oct 2567%Jul 2941%Jul 2941%Sep 1354%Sep 1354%Jun 1755%Jun 1755%NowNowclearmostly cloudyovercastmostly clearpartly cloudy
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Harry P Williams Memorial Airport varies significantly throughout the year.

The wetter season lasts 3.3 months, from June 2 to September 11, with a greater than 41% chance of a given day being a wet day. The chance of a wet day peaks at 60% on July 7.

The drier season lasts 8.7 months, from September 11 to June 2. The smallest chance of a wet day is 23% on October 28.

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 60% on July 7.

Daily Chance of Precipitation

Daily Chance of Precipitation at Harry P Williams Memorial AirportwetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jul 760%Jul 760%Oct 2823%Oct 2823%Jun 241%Jun 241%Sep 1141%Sep 1141%NowNowrain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

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. Harry P Williams Memorial Airport experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year at Harry P Williams Memorial Airport. The most rain falls during the 31 days centered around June 27, with an average total accumulation of 5.9 inches.

The least rain falls around October 13, with an average total accumulation of 3.7 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

The length of the day at Harry P Williams Memorial Airport varies significantly over the course of the year. In 2020, the shortest day is December 21, with 10 hours, 14 minutes of daylight; the longest day is June 20, with 14 hours, 3 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight at Harry P Williams Memorial AirportJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 1912 hr, 7 minMar 1914 hr, 3 minJun 2014 hr, 3 minJun 2012 hr, 9 minSep 2212 hr, 9 minSep 2210 hr, 14 minDec 2110 hr, 14 minDec 21nightnightday
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 6:04 AM on June 10, and the latest sunrise is 1 hour, 18 minutes later at 7:22 AM on March 8. The earliest sunset is at 5:05 PM on December 2, and the latest sunset is 3 hours, 4 minutes later at 8:09 PM on June 30.

Daylight saving time (DST) is observed at Harry P Williams Memorial Airport during 2020, starting in the spring on March 8, lasting 7.8 months, and ending in the fall on November 1.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time at Harry P Williams Memorial AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 106:04 AMJun 106:04 AM8:09 PMJun 308:09 PMJun 30Dec 25:05 PMDec 25:05 PM7:22 AMMar 87:22 AMMar 8Mar 8DSTMar 8DSTDSTNov 1DSTNov 1daynightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2020. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Harry P Williams Memorial Airport experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 6.3 months, from April 15 to October 25, 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 20, with muggy conditions 98% of the time.

The least muggy day of the year is January 16, with muggy conditions 4% of the time.

Humidity Comfort Levels

Humidity Comfort Levels at Harry P Williams Memorial AirportmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jan 164%Jan 164%98%Jul 2098%Jul 20Apr 1528%Apr 1528%Oct 2528%Oct 2528%NowNowmiserablemiserableoppressiveoppressivedrydryhumidhumidmuggymuggy
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed at Harry P Williams Memorial Airport experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.9 months, from September 26 to May 21, with average wind speeds of more than 9.1 miles per hour. The windiest day of the year is December 26, with an average hourly wind speed of 11.5 miles per hour.

The calmer time of year lasts for 4.1 months, from May 21 to September 26. The calmest day of the year is August 7, with an average hourly wind speed of 6.7 miles per hour.

Average Wind Speed

Average Wind Speed at Harry P Williams Memorial AirportwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mph14 mph16 mph18 mphDec 2611.5 mphDec 2611.5 mphAug 76.7 mphAug 76.7 mphSep 269.1 mphSep 269.1 mphMay 219.1 mphMay 219.1 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction at Harry P Williams Memorial Airport varies throughout the year.

The wind is most often from the south for 5.0 months, from February 21 to July 20 and for 2.0 weeks, from August 8 to August 22, with a peak percentage of 54% on June 3. 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 19. The wind is most often from the north for 3.1 months, from November 19 to February 21, with a peak percentage of 37% on January 1.

Wind Direction

Wind Direction at Harry P Williams Memorial AirportNSWSENJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

Harry P Williams Memorial Airport 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 30 to September 26, with an average temperature above 81°F. The day of the year with the warmest water is August 5, with an average temperature of 86°F.

The time of year with cooler water lasts for 3.3 months, from December 7 to March 17, with an average temperature below 66°F. The day of the year with the coolest water is January 28, with an average temperature of 61°F.

Average Water Temperature

Average Water Temperature at Harry P Williams Memorial AirportwarmcoolcoolJanFebMarAprMayJunJulAugSepOctNovDec55°F60°F65°F70°F75°F80°F85°F90°FAug 586°FAug 586°F61°FJan 2861°FJan 28May 3081°FMay 3081°FSep 2681°FSep 2681°FDec 766°FDec 766°FMar 1766°FMar 1766°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is at Harry P Williams Memorial Airport 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 Harry P Williams Memorial Airport for general outdoor tourist activities are from late March to mid May and from late September to late October, with a peak score in the last week of April.

Tourism Score

Tourism Score at Harry P Williams Memorial Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.66.63.13.16.36.33.93.9NowNow precipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

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 Harry P Williams Memorial Airport for hot-weather activities are from early May to late June and from late August to late September, with a peak score in the first week of June.

Beach/Pool Score

Beach/Pool Score at Harry P Williams Memorial AirportJanFebMarAprMayJunJulAugSepOctNovDec02468106.16.10.80.85.75.75.05.0NowNow precipitationprecipitationcloudscloudstemperaturetemperaturebeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

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.

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season at Harry P Williams Memorial Airport typically lasts for 10 months (317 days), from around February 5 to around December 18, rarely starting after March 6, or ending before November 23.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season at Harry P Williams Memorial Airportgrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Feb 550%Feb 550%Dec 1850%Dec 1890%Mar 690%Mar 690%Nov 2390%Nov 2317%Jan 917%Jan 9Jul 9100%Jul 9100%NowNowcoldcoolcomfortablewarmhotvery cold
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms at Harry P Williams Memorial Airport should appear around January 16, only rarely appearing before January 10 or after January 28.

Growing Degree Days

Growing Degree Days at Harry P Williams Memorial AirportJanFebMarAprMayJunJulAugSepOctNovDec0°F1,000°F2,000°F3,000°F4,000°F5,000°F6,000°F7,000°FJan 1690°FJan 1690°FApr 6900°FApr 6900°FMay 191,800°FMay 191,800°FDec 316,826°FDec 316,826°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

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 2.6 months, from March 30 to June 19, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is May 18, with an average of 6.6 kWh.

The darker period of the year lasts for 2.5 months, from November 15 to February 1, with an average daily incident shortwave energy per square meter below 3.8 kWh. The darkest day of the year is December 23, with an average of 3.1 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy at Harry P Williams Memorial AirportbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWhMay 186.6 kWhMay 186.6 kWhDec 233.1 kWhDec 233.1 kWhMar 305.9 kWhMar 305.9 kWhFeb 13.8 kWhFeb 13.8 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Harry P Williams Memorial Airport are 29.712 deg latitude, -91.334 deg longitude, and 3 ft elevation.

The topography within 2 miles of Harry P Williams Memorial Airport is essentially flat, with a maximum elevation change of 10 feet and an average elevation above sea level of 4 feet. Within 10 miles is also essentially flat (39 feet). Within 50 miles is essentially flat (141 feet).

The area within 2 miles of Harry P Williams Memorial Airport is covered by cropland (49%) and herbaceous vegetation (49%), within 10 miles by herbaceous vegetation (79%) and cropland (12%), and within 50 miles by herbaceous vegetation (50%) and water (33%).

Data Sources

This report illustrates the typical weather at Harry P Williams Memorial Airport, 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

Harry P Williams Memorial Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.

In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.

The stations on which we may fall back include but are not limited to Salt Point; Acadiana Regional Airport; Houma-Terrebonne Airport; Abbeville Chris Crusta Memorial Airport; Lafayette Regional Airport; Baton Rouge Metropolitan Airport; Louis Armstrong New Orleans International Airport; and Galliano, South Lafourche Airport.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

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.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.