Bilecik has a transitional climate due to its location in the Marmara Region of Turkey, which reflects the effects of both the Marmara and Central Anatolia Regions in the city's climate. Generally, winters are cold and rainy, while summers are hot and relatively dry. Spring and fall seasons are generally mild and rainy.
During the winter months, temperatures usually hover around 0°C, but can drop below zero on some cold days. Snowfall can occur and snow cover can remain for several days or weeks, especially in the higher elevations. This offers some opportunities for winter tourism in the city, but can make daily life and transportation difficult for locals.
In summer, temperatures usually range between 25°C and 35°C. July and August are the hottest months of the year and can experience severe heat waves. Hot weather can cause health problems, especially for the elderly and those with chronic diseases. High temperatures also lead to increased water consumption and put pressure on local water resources.
In Bilecik, winds generally blow from the north and northwest directions. These winds can gain speed especially in spring and fall and are sometimes felt as strong winds. This effect of the wind can be particularly pronounced on agricultural activities and can cause allergic reactions by increasing dust and pollen transportation.
Humidity varies throughout the year. While humidity is lower in summer, it increases in winter and especially during rainy periods. High humidity can be challenging for people with respiratory problems. Rainfall usually intensifies in the fall and winter months, which can lead to intermittent flooding and inundation.
Bilecik's climate can affect life in the city in general; for example, the need for heating increases in winter, while more energy is used to cool down in summer. Furthermore, such marked seasonal variability requires seasonal planning in sectors such as clothing and agriculture. Thus, the inhabitants of Bilecik have to organize their lives by adapting to these climatic variations.