Average Weather on September 21 at Poitiers–Biard Airport France
On September 21, the temperature at Poitiers–Biard Airport typically ranges from 52°F to 69°F and is rarely below 44°F or above 80°F.
For reference, on August 3, the hottest day of the year, temperatures at Poitiers–Biard Airport typically range from 57°F to 79°F, while on February 8, the coldest day of the year, they range from 34°F to 47°F.
The coolest time of the day is from 1:15 AM to 9:15 AM, with the coldest at 7:15 AM, at which time the temperature is below 57°F three days out of four, and below 61°F nine days out of ten.
The warmest time of the day is from 12:45 PM to 7:30 PM, with the hottest at 4:30 PM, at which time the temperature is above 64°F three days out of four, and above 60°F nine days out of ten.
The day has gained half its heat by 10:45 AM and lost it again by 9:15 PM.
Average Temperature on September 21
The figure below shows you a compact characterization of the range of temperatures experienced on September 21 throughout the historical record. The horizontal axis is the time of day and the colored stacked areas indicate the percentage of hours spent in various temperature bands.
Temperature Bands on September 21
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
Compared to September 21 (excluding 30 days before and after), June 3 has the most similar daily average high and low temperatures.
At Poitiers–Biard Airport on September 21, the average percentage of the sky covered by clouds does not show significant systematic variation over the course of the day, with the percentage of time that the sky is overcast or mostly cloudy remaining about 46% throughout the day.
For reference, on January 3, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 72%, while on July 24, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 69%.
Cloud Cover Categories on September 21
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
On average, there is a 23% chance that more than 0.04 inches of total precipitation will fall at Poitiers–Biard Airport throughout the day on September 21, all of which can be expected to be rain.
For reference, the year's highest daily chance of precipitation is 33% on December 30, and its lowest chance is 16% on August 27.
For those 23% of years with precipitation on September 21, the chart below shows when throughout the day that precipitation is more or less likely to occur, excluding hourly accumulations of less than 0.01 inches. If precipitation were equally likely throughout the day, all hours would report 4.2% (100% divided by 24 hours).
Precipitation is most likely between 1 PM and 2 PM, and least likely between 1 AM and 2 AM.
Hourly Share of Precipitation on September 21
At Poitiers–Biard Airport on Saturday, September 21, 2019, the Sun rises at 7:43 AM and sets 12 hours, 16 minutes later, at 7:59 PM. Solar noon is at 1:51 PM.
For reference, on June 21, the longest day of the year, the Sun rises at 6:05 AM and sets 15 hours, 50 minutes later, at 9:55 PM, while on December 22, the shortest day of the year, it rises at 8:40 AM and sets 8 hours, 34 minutes later, at 5:14 PM.
Civil twilight, the period before the Sun has risen or after the Sun has set during which time it is possible to engage in most outdoor activities without artificial lighting, begins and ends 30 minutes before sunrise and after sunset, at 7:13 AM and 8:29 PM respectively.
Nautical twilight, during which time it is possible to clearly discern the horizon (e.g., for navigational purposes), begins and ends 1 hour, 6 minutes before sunrise and after sunset, at 6:37 AM and 9:04 PM respectively.
Astronomical twilight, outside of which it is possible to make the most sensitive of astronomical observations, begins and ends 1 hour, 42 minutes before sunrise and after sunset, at 6:01 AM and 9:41 PM respectively.
Solar Elevation on September 21, 2019
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.
At Poitiers–Biard Airport on September 21, the chance of muggy conditions does not change significantly over the course of the day, remaining around 1% throughout.
Humidity Comfort Levels on September 21
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 Poitiers–Biard Airport on September 21 varies throughout the day, with a daily average of 8.8 miles per hour.
The windiest time of day is around 3:30 PM, with an average hourly wind speed of 11.1 miles per hour, mostly staying between 7.2 miles per hour and 14.5 miles per hour, and rarely falling below 4.4 miles per hour or exceeding 18.7 miles per hour.
The calmest time of day is around 5:15 AM, with an average hourly wind speed of 7.4 miles per hour, mostly staying between 5.1 miles per hour and 9.1 miles per hour, and rarely falling below 3.4 miles per hour or exceeding 12.1 miles per hour.
For reference, on December 30, the windiest day of the year, the daily average wind speed is 11.0 miles per hour, while on August 5, the calmest day of the year, the daily average wind speed is 7.9 miles per hour.
Wind Speed on September 21
Over the entire course of September 21 at Poitiers–Biard Airport, the hourly average wind direction, in order of prevalence, is from the west (31%), south (24%), east (23%), and north (21%).
Wind Direction on September 21
Shortwave Solar Power
This section discusses the incident shortwave solar power 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 peak incident shortwave solar power per square meter is 0.58 kilowatts at around 1:45 PM.
In contrast, the corresponding value on July 7, the brightest day of the year, is 0.79 kilowatts at around 12:45 PM. The corresponding value on December 27, the darkest day of the year, is 0.21 kilowatts at around 12:15 PM.
Shortwave Solar Power on September 21
For the purposes of this report, the geographical coordinates of Poitiers–Biard Airport are 46.588 deg latitude, 0.307 deg longitude, and 384 ft elevation.
The topography within 2 miles of Poitiers–Biard Airport contains only modest variations in elevation, with a maximum elevation change of 249 feet and an average elevation above sea level of 374 feet. Within 10 miles also contains only modest variations in elevation (351 feet). Within 50 miles contains only modest variations in elevation (1,440 feet).
The area within 2 miles of Poitiers–Biard Airport is covered by artificial surfaces (52%), cropland (34%), and trees (14%), within 10 miles by cropland (60%) and trees (20%), and within 50 miles by cropland (63%) and grassland (18%).
This report illustrates the typical weather at Poitiers–Biard 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
Poitiers–Biard 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 Niort-Souché, Angoulême – Cognac International Airport, Tours Val de Loire Airport, Cognac-Châteaubernard Air Base, Limoges-Bellegarde, Angers – Loire Airport, Angers-Avrillé, and Le Mans-Arnage.
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.
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.