The Neretva valley has a typical Mediterranean climate with dry hot summers and regular seasonality. Given the advantages for life and encouragement of human activity, ecologists call this ‘the olive tree climate’.
The delta has hills on its northern, north-eastern and southern sides, whilst towards the west it is open to the sea and marine influences. This causes the creation of various micro-climates, with winter temperatures in the area between Metković and Opuzen one or two degrees lower, affecting the growth of citrus trees in the upper part. There are no strong winds in the Neretva valley but eastern winds are somewhat stronger than western winds. As in other Croatian coastal areas, all the northern, northwestern and eastern winds are called the bum - a cold wind most frequently accompanied by fair and sunny weather, favoured especially by hunters. The group of south-eastern and south winds (frequent in the autumn and winter) are called the jugo.
The maestral (Zmorac), is a western summer wind produced by a great difference between the warmth of the land and the sea. Deep in the interior of the valley, the fresh sea air alleviates the sultriness of summer afternoons. The summers of the Neretva are long, warm and dry, and winters gentle and wet. There are 2,700 average annual hours of sun and the mean annual temperature amounts to 15.7°C. The coldest months are December, January and February; even then the temperature rarely falls below zero. The warmest months are July and August. The temperature in August can reach 35 °C or even 40 °C. Average annual rainfall is 1300 mm, mostly in the winter. Mist and snow are rare.
