Climate and Average Weather Year Round in Darreh Shahr Iran

In Darreh Shahr, the summers are sweltering, arid, and clear and the winters are cold and mostly clear. Over the course of the year, the temperature typically varies from 36°F to 108°F and is rarely below 26°F or above 112°F.

Based on the beach/pool score, the best times of year to visit Darreh Shahr for hot-weather activities are from late May to late June and from late August to early October.

The hot season lasts for 3.7 months, from May 31 to September 20, with an average daily high temperature above 97°F. The hottest month of the year in Darreh Shahr is July, with an average high of 107°F and low of 77°F.

The cool season lasts for 3.5 months, from November 25 to March 8, with an average daily high temperature below 66°F. The coldest month of the year in Darreh Shahr is January, with an average low of 36°F and high of 56°F.

In Darreh Shahr, 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 Darreh Shahr begins around May 21 and lasts for 4.8 months, ending around October 13.

The clearest month of the year in Darreh Shahr is July, during which on average the sky is clear, mostly clear, or partly cloudy 100% of the time.

The cloudier part of the year begins around October 13 and lasts for 7.2 months, ending around May 21.

The cloudiest month of the year in Darreh Shahr is December, during which on average the sky is overcast or mostly cloudy 38% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Darreh Shahr varies throughout the year.

The wetter season lasts 6.7 months, from October 19 to May 10, with a greater than 8% chance of a given day being a wet day. The month with the most wet days in Darreh Shahr is March, with an average of 4.6 days with at least 0.04 inches of precipitation.

The drier season lasts 5.3 months, from May 10 to October 19. The month with the fewest wet days in Darreh Shahr is August, with an average of 0.2 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Darreh Shahr is March, with an average of 4.6 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 15% on January 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. Darreh Shahr experiences some seasonal variation in monthly rainfall.

The rainy period of the year lasts for 6.8 months, from October 15 to May 10, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in Darreh Shahr is March, with an average rainfall of 1.2 inches.

The rainless period of the year lasts for 5.2 months, from May 10 to October 15. The month with the least rain in Darreh Shahr is August, with an average rainfall of 0.0 inches.

The length of the day in Darreh Shahr varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 58 minutes of daylight; the longest day is June 21, with 14 hours, 21 minutes of daylight.

The earliest sunrise is at 5:10 AM on June 12, and the latest sunrise is 2 hours, 14 minutes later at 7:24 AM on January 9. The earliest sunset is at 5:13 PM on December 3, and the latest sunset is 2 hours, 20 minutes later at 7:33 PM on June 29.

Daylight saving time (DST) is not observed in Darreh Shahr during 2024.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

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 Darreh Shahr, 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 Darreh Shahr experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 5.3 months, from April 29 to October 6, with average wind speeds of more than 6.8 miles per hour. The windiest month of the year in Darreh Shahr is June, with an average hourly wind speed of 7.9 miles per hour.

The calmer time of year lasts for 6.8 months, from October 6 to April 29. The calmest month of the year in Darreh Shahr is December, with an average hourly wind speed of 5.7 miles per hour.

The predominant average hourly wind direction in Darreh Shahr varies throughout the year.

The wind is most often from the north for 9.4 months, from February 15 to November 26, with a peak percentage of 44% on September 15. The wind is most often from the east for 2.6 months, from November 26 to February 15, with a peak percentage of 34% on January 1.

To characterize how pleasant the weather is in Darreh Shahr 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 Darreh Shahr for general outdoor tourist activities are from early April to mid May and from late September to early November, with a peak score in the third week of October.

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 Darreh Shahr for hot-weather activities are from late May to late June and from late August to early October, with a peak score in the third week of September.

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.

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 in Darreh Shahr typically lasts for 9.5 months (289 days), from around February 25 to around December 10, rarely starting before January 25 or after March 24, and rarely ending before November 19 or after January 1.

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 in Darreh Shahr should appear around February 9, only rarely appearing before January 27 or after February 28.

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 extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.3 months, from May 15 to August 24, with an average daily incident shortwave energy per square meter above 7.6 kWh. The brightest month of the year in Darreh Shahr is June, with an average of 8.7 kWh.

The darker period of the year lasts for 3.4 months, from November 1 to February 12, with an average daily incident shortwave energy per square meter below 4.1 kWh. The darkest month of the year in Darreh Shahr is December, with an average of 3.0 kWh.

For the purposes of this report, the geographical coordinates of Darreh Shahr are 33.144 deg latitude, 47.380 deg longitude, and 2,165 ft elevation.

The topography within 2 miles of Darreh Shahr contains very significant variations in elevation, with a maximum elevation change of 945 feet and an average elevation above sea level of 2,247 feet. Within 10 miles contains very significant variations in elevation (5,417 feet). Within 50 miles also contains extreme variations in elevation (9,012 feet).

The area within 2 miles of Darreh Shahr is covered by cropland (35%), shrubs (35%), and sparse vegetation (25%), within 10 miles by shrubs (35%) and sparse vegetation (30%), and within 50 miles by shrubs (49%) and trees (27%).