Herceg Novi has approximately 200 sunny days a year. In July and August there are approximately 11 sunny hours per day. Average annual temperature is 16.2 °C (61.2 °F) (similar to that of Naples and Lisbon). There are frequent slight temperature oscillations; the average daily temperature fluctuation is only 4 °C (39 °F). Average temperature from May to September is about 25 °C (77 °F), which provides a swimming season over 5 months long since the average summer sea temperature is rather high, between 22 °C (72 °F) - 26 °C (79 °F).
The annual average precipitation is 1,930 millimetres (76 in). Relative air humidity is at its highest level, 80%, in the fall. Its lowest level, 63%, comes in the summer