Travel on weekdays from mid-July through the end of August at this price. Searching on Lufthansa we found seats departing SFO on Sunday, August 5 and returning from ARN on Monday, August 13, 2018. Lufthansa also has great deals on Spring flights for only $484, but we chose to highlight this Summer fare because flights are usually a few hundred dollars more during that period.
Need a room in Stockholm? This is what is available for the provided dates on Hotelwatchdog.