Average Weather in Ad Dilam Saudi Arabia

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2. Saudi Arabia
3. Ar Riyāḑ
4. Ad Dilam

In Ad Dilam, the summers are long, sweltering, and arid; the winters are cool and dry; and it is mostly clear year round. Over the course of the year, the temperature typically varies from 49°F to 111°F and is rarely below 42°F or above 115°F.

The hot season lasts for 4.4 months, from May 14 to September 25, with an average daily high temperature above 103°F. The hottest day of the year is July 27, with an average high of 111°F and low of 87°F.

The cool season lasts for 3.0 months, from November 26 to February 26, with an average daily high temperature below 78°F. The coldest day of the year is January 10, with an average low of 49°F and high of 70°F.

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.

In Ad Dilam, 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 Ad Dilam begins around August 29 and lasts for 3.1 months, ending around December 2. On October 1, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 90% of the time, and overcast or mostly cloudy 10% of the time.

The cloudier part of the year begins around December 2 and lasts for 8.9 months, ending around August 29. On July 21, the cloudiest day of the year, the sky is overcast or mostly cloudy 44% of the time, and clear, mostly clear, or partly cloudy 56% of the time.

Ad Dilam does not experience significant seasonal variation in the frequency of wet days (i.e., those with greater than 0.04 inches of liquid or liquid-equivalent precipitation). The frequency ranges from -0% to 5%, with an average value of 2%.

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 5% on March 17.

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. Ad Dilam experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Ad Dilam. The most rain falls during the 31 days centered around March 11, with an average total accumulation of 0.3 inches.

The least rain falls around June 30, with an average total accumulation of 0.0 inches.

The length of the day in Ad Dilam varies over the course of the year. In 2017, the shortest day is December 21, with 10 hours, 39 minutes of daylight; the longest day is June 21, with 13 hours, 37 minutes of daylight.

The earliest sunrise is at 5:03 AM on June 8, and the latest sunrise is 1 hour, 33 minutes later at 6:36 AM on January 14. The earliest sunset is at 5:03 PM on November 29, and the latest sunset is 1 hour, 40 minutes later at 6:43 PM on July 3.

Daylight saving time (DST) is not observed in Ad Dilam during 2017.

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.

The perceived humidity level in Ad Dilam, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

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 in Ad Dilam experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 2.9 months, from May 23 to August 20, with average wind speeds of more than 4.5 miles per hour. The windiest day of the year is July 6, with an average hourly wind speed of 5.2 miles per hour.

The calmer time of year lasts for 9.1 months, from August 20 to May 23. The calmest day of the year is October 4, with an average hourly wind speed of 3.9 miles per hour.

The predominant average hourly wind direction in Ad Dilam varies throughout the year.

The wind is most often from the east for 2.0 days, from May 22 to May 24 and for 1.4 months, from August 31 to October 12, with a peak percentage of 45% on September 12. The wind is most often from the north for 3.2 months, from May 24 to August 31, with a peak percentage of 75% on July 6. The wind is most often from the south for 7.3 months, from October 12 to May 22, with a peak percentage of 41% on January 1.

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 3.7 months, from May 10 to September 2, with an average daily incident shortwave energy per square meter above 7.4 kWh. The brightest day of the year is June 20, with an average of 8.2 kWh.

The darker period of the year lasts for 2.8 months, from November 10 to February 3, with an average daily incident shortwave energy per square meter below 5.1 kWh. The darkest day of the year is December 13, with an average of 4.3 kWh.

For the purposes of this report, the geographical coordinates of Ad Dilam are 23.991 deg latitude, 47.162 deg longitude, and 1,483 ft elevation.

The topography within 2 miles of Ad Dilam contains only modest variations in elevation, with a maximum elevation change of 167 feet and an average elevation above sea level of 1,477 feet. Within 10 miles contains only modest variations in elevation (558 feet). Within 50 miles contains significant variations in elevation (2,654 feet).

The area within 2 miles of Ad Dilam is covered by bare soil (62%) and cropland (38%), within 10 miles by bare soil (83%) and cropland (17%), and within 50 miles by bare soil (96%).

This report illustrates the typical weather in Ad Dilam, 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 Ad Dilam.

For each station, the records are corrected for the elevation difference between that station and Ad Dilam 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 Ad Dilam is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Ad Dilam and a given station.

The stations contributing to this reconstruction are: Prince Sultan Air Base (87%, 27 kilometers, east) and Riyadh Air Base (13%, 91 kilometers, northwest).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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.