Aasiaat's short summer carries several town events, including Greenland National Day on 21 June, the Midnight Sun Marathon, Aasiaat Kulturfestival, and Nipiaa Rock Festival. Dates and scale can change, so check locally before planning a trip around one event.
The festivals are not the only reason to come, but they are a good way to see the town at its most social. They also make practical sense: summer is already the best season for boats, kayaking, and whale watching.