Climate
The mesoclimatic conditions of the town are influenced by the location of this area in the western part of the Carpathian Mountains, at the borderland of mountains and mountain foothills; and also by large height differences. The microclimate of this area is influenced by considerably differentiated relief, and local land use (built-up areas, agricultural land, coppices and forests). The weather conditions are mainly influenced by polar-sea air masses coming from the Atlantic (about 65% of days per year). The largest frequency of the inflow of these air masses occurs in November and the smallest in March and September. Polar-continental air inflows during about 20% of days annually with a significant high in January, a high frequency in March and a minimum in April and November. Arctic air masses occur in about 6% of days annually with significant highs in April and September and minimum in July. Tropical air masses are the most rare (about 3% of days annually). Their maximum occurs in April. The air masses inflow mainly from the west. In addition, the arrangement of valleys strongly influence wind direction. In the lowland and upland part of Cieszyn Silesia, south-westerly winds are the most frequent (about 12-18%) as well as westerly winds (about 10%). These are followed by northerly and north-westerly winds whereas easterly winds are the least frequent (about 4%).
A percentage of southerly winds are represented by föhn winds, which usually occur in winter. Their positive influence consists in the lowering of relative humidity, the lowering of temperature and the liquidation of thermal inversions, which are quite frequent in this area. Their negative influence consists in the occurrence of sudden pressure changes. The frequency of these winds at the foothills of Beskidy Mountains is as large as 47%.
The characteristic parameters of Cieszyn climate include (data from the period 1961-1990):
• mean annual air temperature: 8.20C
• annual precipitation totals:
• 939 mm (period 1931-1990),
• in dry years 700-800 mm,
• in wet years up to 1200 mm
• mean annual number of foggy days: 40-60
• vegetation period: 224 days
• period without ground frost: 180 days
• mean period of snow cover occurrence: 60-70 days