Climate and Average Weather Year Round in İznik Turkey

In İznik, the summers are warm, dry, and clear and the winters are very cold and partly cloudy. Over the course of the year, the temperature typically varies from 34°F to 88°F and is rarely below 26°F or above 95°F.

Based on the beach/pool score, the best time of year to visit İznik for hot-weather activities is from late June to late August.

The hot season lasts for 3.3 months, from June 7 to September 15, with an average daily high temperature above 80°F. The hottest month of the year in İznik is July, with an average high of 87°F and low of 64°F.

The cool season lasts for 3.6 months, from November 27 to March 14, with an average daily high temperature below 56°F. The coldest month of the year in İznik is January, with an average low of 35°F and high of 49°F.

In İznik, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.

The clearer part of the year in İznik begins around May 28 and lasts for 4.1 months, ending around September 30.

The clearest month of the year in İznik is July, during which on average the sky is clear, mostly clear, or partly cloudy 95% of the time.

The cloudier part of the year begins around September 30 and lasts for 7.9 months, ending around May 28.

The cloudiest month of the year in İznik is December, during which on average the sky is overcast or mostly cloudy 61% 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 İznik varies throughout the year.

The wetter season lasts 8.2 months, from October 2 to June 9, with a greater than 18% chance of a given day being a wet day. The month with the most wet days in İznik is December, with an average of 8.7 days with at least 0.04 inches of precipitation.

The drier season lasts 3.8 months, from June 9 to October 2. The month with the fewest wet days in İznik is July, with an average of 2.8 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 İznik is December, with an average of 8.1 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 28% on December 12.

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. İznik experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in İznik. The month with the most rain in İznik is December, with an average rainfall of 2.5 inches.

The month with the least rain in İznik is July, with an average rainfall of 0.7 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. İznik experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 1.8 months, from January 10 to March 2, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in İznik is February, with an average snowfall of 1.8 inches.

The snowless period of the year lasts for 10 months, from March 2 to January 10. The least snow falls around July 24, with an average total accumulation of 0.0 inches.

The length of the day in İznik varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 17 minutes of daylight; the longest day is June 20, with 15 hours, 4 minutes of daylight.

The earliest sunrise is at 5:30 AM on June 14, and the latest sunrise is 2 hours, 54 minutes later at 8:24 AM on January 5. The earliest sunset is at 5:34 PM on December 7, and the latest sunset is 3 hours, 1 minute later at 8:35 PM on June 27.

Daylight saving time (DST) is not observed in İznik 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.

İznik experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 2.7 months, from June 17 to September 8, during which time the comfort level is muggy, oppressive, or miserable at least 8% of the time. The month with the most muggy days in İznik is August, with 7.4 days that are muggy or worse.

The least muggy day of the year is February 23, when muggy conditions are essentially unheard of.

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 İznik experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 3.8 months, from December 9 to April 4, with average wind speeds of more than 6.3 miles per hour. The windiest month of the year in İznik is February, with an average hourly wind speed of 7.0 miles per hour.

The calmer time of year lasts for 8.2 months, from April 4 to December 9. The calmest month of the year in İznik is May, with an average hourly wind speed of 5.6 miles per hour.

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

The wind is most often from the north for 8.6 months, from February 20 to November 9, with a peak percentage of 73% on August 3. The wind is most often from the south for 3.4 months, from November 9 to February 20, with a peak percentage of 44% on January 1.

İznik 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 3.6 months, from June 14 to October 1, with an average temperature above 69°F. The month of the year in İznik with the warmest water is August, with an average temperature of 74°F.

The time of year with cooler water lasts for 3.9 months, from December 17 to April 13, with an average temperature below 52°F. The month of the year in İznik with the coolest water is February, with an average temperature of 46°F.

To characterize how pleasant the weather is in İznik 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 time of year to visit İznik for general outdoor tourist activities is from late May to late September, with a peak score in the second 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 İznik for hot-weather activities is from late June to late August, with a peak score in the last week of July.

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 İznik typically lasts for 8.1 months (250 days), from around March 21 to around November 26, rarely starting before February 24 or after April 10, and rarely ending before November 2 or after December 21.

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 İznik should appear around March 7, only rarely appearing before February 13 or after April 4.

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 3.1 months, from May 17 to August 21, with an average daily incident shortwave energy per square meter above 6.6 kWh. The brightest month of the year in İznik is July, with an average of 7.7 kWh.

The darker period of the year lasts for 3.6 months, from October 28 to February 17, with an average daily incident shortwave energy per square meter below 2.9 kWh. The darkest month of the year in İznik is December, with an average of 1.7 kWh.

For the purposes of this report, the geographical coordinates of İznik are 40.429 deg latitude, 29.721 deg longitude, and 325 ft elevation.

The topography within 2 miles of İznik contains very significant variations in elevation, with a maximum elevation change of 928 feet and an average elevation above sea level of 363 feet. Within 10 miles contains very significant variations in elevation (3,865 feet). Within 50 miles also contains extreme variations in elevation (8,389 feet).

The area within 2 miles of İznik is covered by cropland (47%), water (27%), and trees (15%), within 10 miles by trees (42%) and cropland (39%), and within 50 miles by trees (49%) and cropland (33%).