Definitely do NOT count on it.
As of March 2019: The Central Library has an early bird parking rate on weekdays. If you park before 9:30 AM (garage opens at 7 AM) and leave by 6 PM then you only pay a flat $16 for the entire day. This may seem high, but for that area of downtown it's not (the building across the street charges a $19 early bird special). If you're there for only a few hours they charge you by the hour. I park there occasionally and rarely have issues finding a spot before 8:30 AM. After that it can be slim pickings. Also, the layout is a repeating pattern of 3 consecutive spots sandwiched between cement pillars. The spots next to the pillars are narrow. I have a small car and can squeeze in to those spots. If you drive a larger sedan, SUV or truck then you may have issues if you're not there early enough to grab a middle spot. They also have a flat parking rate on the weekends that is much lower.
It's downtown, so parking during the day on a weekday might be a bit of a challenge
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