The best time to visit Rummu is during the summer months, from June to August, when the weather is warm and pleasant for outdoor activities.During these months, the temperatures are ideal for swimming, diving, and paddleboarding in the crystal-clear waters of the Rummu quarry. The long daylight hours also mean you have more time to explore the unique submerged prison ruins and the surrounding landscape. It's also when various local businesses and services around the quarry are fully operational.For those looking for a quieter experience, late spring (May) or early autumn (September) can also be good options. The weather is still generally pleasant, though cooler, and there are fewer visitors, which can lead to a more relaxed exploration of the area.