The town of Omis has a mild Mediterranean climate with mild and rainy winters and warm and dry summers with a large number of sunny hours annually. There is an average of 2700 hours of sunshine, i.e. a daily average of 7.3 hrs. During summer, it rises even to an average of 11.3 hours, 7.4 hours in spring, 6.3 hours in fall, and 4,2 hours in winter. This high rate of sunny weather has an influence on the relatively high yearly and daily temperature of the air. The average air temperature is 16.0 degrees Celsius. January is in average the coldest with 7.7 degrees Celsius, and July is the warmest (25.6 degrees Celsius) month of the year. This favourable climate and the flow of warm sea currents have an influence on the high temperature of the sea, with a summer average of 22.6 degrees Celsius, that is, an average yearly approximate of 17.5 degrees Celsius.
The microclimate of the town of Omis is largely influenced by the river of Cetina. Through the canyon of the river of Cetina, there is a constant flow of fresh, cold air from the hinterland of Omis. Thanks to this, the town of Omis is always few degrees colder than neighbouring places, which is very helpful during hot summer nights, but not so welcome during the winter, especially when the cold north-eastern wind blows. Just few kilometres upstream from the mouth of the river Cetina, you can find completely different climate, damp forests of deciduous trees and green meadows. During hot summer days, the banks of river Cetina offer refreshment and are perfect getaway from hot and crowded beaches. Omis riviera, thanks to its location under high coastal mountains, is known in Croatia for the strength of north-east wind Bura. This is especially true for the eastern part of Omis riviera (from Omis to Pisak), where the strength of the wind is additionaly reinforced by mountain Biokovo. The western part of the riviera (from Omis to Podstrana) is well protected from these winds, and the climate there is much warmer during cold winter days when north winds blow.
The local and periodical (seasonal) winds also help to maintain a favourable climate. Among them, the most distinct are the local winds "Jugo" or "Sirocco" (south-east wind) and "Bura" (north-east wind), which show up during the entire year, but especially well marked during winter, when their bio-climatic activity is at it's peak. The frequency is of these winds is 35 to 55% annually. The Adriatic Sea acts as a natural reservoir of relatively warm water temperatures of 10-26°C and this is the most important indicator of climate in the wider area of the county. In the early spring and summer, the most characteristic wind is "Maestral" which has important thermoregulation activity, because as it is a sea wind, it brings a favourable coolness. "Maestral" is replaced by the night breeze from the north ("Burin"), which cools the overheated dry land. Opposite to"Maestral" is "Levanat", an eastern cool wind that blows on Omis riviera only on rare occasions, usually as a messenger of changing weather and arrival of "Jugo" wind. "Tramuntana" is one of the strongest winds on the Adriatic sea. It is a cold wind that blows from the north, usually after the rain storms and generally indicates unstable weather. It is similar to "Maestral" but it can blow much stronger, raises large waves and it can blow in any period of the year.
Rainfall on the this area also has Mediterranean characteristics. It amounts to only 809 mm (32 in) yearly, but it is favourably dispersed, so that Spring and especially Summer is mostly dry, while moderate rains fall in Fall and Winter season. Snow is an exceptionally rare phenomenon on the coast. Regarding snow some interesting facts have been recorded: in January of 1510 it snowed on the islands and along the coast, and low temperatures lasted for long. Harsh winters were recorded in 1709, 1782, 1788, 1806, 1929, 1941, and 1942, when low temperatures caused significant damage to olives, figs and winter crops. The snow is the hinterland of Omis is regular occurrence.
