Weather condition is changeable in this time of year, temperature could vary from 10 °C to 25 °C with possible rain. You should have clothes for warm and cold weather.
More about weather:
Bor Lake is situated on 438 meter above the sea level, at the foot of Crni Vrh(1043 meters) mountain and its weather condition is influenced by the mountain. Bor Lake weather condition is something between Crni Vrh and Bor (353 meters) weather condition, similar to Crni Vrh weather and always few degree warmer.