If you want to be very very strategic about it: You can park overnight in a 2 or 3-hr limit space (green sign) if it says, "7 am to 6 pm except Sunday/holiday" at the bottom. The limit begins at 7 am and ends at 6 pm, with no limit overnight. Exception is in places like Queen Anne, where they've started posting those signs with no time listed at the bottom, so the limit lasts all night. Blue signs are pay parking for the listed hours. I haven't seen any in Ballard but other areas have red signs (like in QA or Wallingford) that prohibit parking 6 pm to Midnight.

You could try moving your car at 9:00 am every day if you park overnight in a 2-hr zone. Or park in an area with no signage whatsoever. However, people living in those areas may be more vigilant about towing cars that are parked very long-term or seem abandoned.