In Batumi, in June the temperature during the day is 25-30°C, and at night it goes down to 15-20°C. But it gets hotter at the end of the month: during the day the temperature will be above 30°C and at night - from 20°C. The sea in June warms up to a temperature of 23-24°C. Therefore, in the first half of June it may still not quite comfortable to swim, but around the third decade of the month the water will be warm enough for comfortable swimming.