Lava caving in Iceland is available year-round. However, the best time for your Icelandic lava caving trip is in July and August. These two months see the warmest temperatures, the least amount of rain, and the most daylight. However, if you’d like to see the Northern Lights, or Aurora Borealis, then come February to March or September to October, especially during the equinoxes. Winter is understandably frigid; but, it is also the best time to see some impressive ice formations while lava caving in Iceland. So, bring your thermals and a sense of humor!