Climate and Average Weather Year Round at Ilam Iran

At Ilam, the summers are arid, clear, and hot and the winters are very cold and mostly clear. Over the course of the year, the temperature typically varies from 32°F to 98°F and is rarely below 26°F or above 103°F.

Based on the beach/pool score, the best time of year to visit Ilam for hot-weather activities is from mid June to early September.

The hot season lasts for 3.6 months, from June 2 to September 21, with an average daily high temperature above 88°F. The hottest month of the year at Ilam is July, with an average high of 98°F and low of 71°F.

The cool season lasts for 3.6 months, from November 27 to March 15, with an average daily high temperature below 58°F. The coldest month of the year at Ilam is January, with an average low of 32°F and high of 49°F.

At Ilam, 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 Ilam begins around May 22 and lasts for 4.7 months, ending around October 13.

The clearest month of the year at Ilam 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 7.3 months, ending around May 22.

The cloudiest month of the year at Ilam 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 at Ilam 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 at Ilam is March, with an average of 4.9 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 at Ilam 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 at Ilam is March, with an average of 4.8 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 16% on March 22.

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. Ilam 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 at Ilam is March, with an average rainfall of 1.3 inches.

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

The length of the day at Ilam varies significantly over the course of the year. In 2026, the shortest day is December 22, with 9 hours, 55 minutes of daylight; the longest day is June 21, with 14 hours, 23 minutes of daylight.

The earliest sunrise is at 5:13 AM on June 13, and the latest sunrise is 2 hours, 16 minutes later at 7:29 AM on January 8. The earliest sunset is at 5:15 PM on December 5, and the latest sunset is 2 hours, 23 minutes later at 7:38 PM on June 29.

Daylight saving time (DST) is not observed at Ilam during 2026.

The figure below presents a compact representation of key lunar data for 2026. 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 at Ilam, 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 at Ilam experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.5 months, from May 14 to September 29, with average wind speeds of more than 8.1 miles per hour. The windiest month of the year at Ilam is June, with an average hourly wind speed of 9.3 miles per hour.

The calmer time of year lasts for 7.5 months, from September 29 to May 14. The calmest month of the year at Ilam is December, with an average hourly wind speed of 6.8 miles per hour.

The predominant average hourly wind direction at Ilam varies throughout the year.

The wind is most often from the west for 1.2 months, from April 8 to May 15, with a peak percentage of 32% on May 14. The wind is most often from the north for 4.9 months, from May 15 to October 13, with a peak percentage of 46% on September 4. The wind is most often from the east for 5.8 months, from October 13 to April 8, with a peak percentage of 44% on January 1.

To characterize how pleasant the weather is at Ilam 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 Ilam for general outdoor tourist activities are from mid May to mid June and from early September to mid October, with a peak score in the last week of September.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Ilam for hot-weather activities is from mid June to early September, with a peak score in the first week of August.

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 at Ilam typically lasts for 8.5 months (261 days), from around March 13 to around November 29, rarely starting before February 16 or after April 5, and rarely ending before November 5 or after December 25.

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 Ilam should appear around March 14, only rarely appearing before March 3 or after March 30.

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 16 to August 24, with an average daily incident shortwave energy per square meter above 7.6 kWh. The brightest month of the year at Ilam is June, with an average of 8.7 kWh.

The darker period of the year lasts for 3.3 months, from November 2 to February 11, with an average daily incident shortwave energy per square meter below 4.1 kWh. The darkest month of the year at Ilam is December, with an average of 3.0 kWh.

For the purposes of this report, the geographical coordinates of Ilam are 33.587 deg latitude, 46.405 deg longitude, and 4,390 ft elevation.

The topography within 2 miles of Ilam contains very significant variations in elevation, with a maximum elevation change of 1,119 feet and an average elevation above sea level of 4,456 feet. Within 10 miles contains very significant variations in elevation (6,394 feet). Within 50 miles also contains extreme variations in elevation (9,108 feet).

The area within 2 miles of Ilam is covered by shrubs (48%) and sparse vegetation (39%), within 10 miles by trees (35%) and shrubs (33%), and within 50 miles by shrubs (38%) and trees (26%).