I'm petite/athletic 5'-0" female looking for a lightweight leak/water proof daypack - will SealLine Urban Backpack suit me?

It depends on what you need it for. If you simply want a backpack for riding your bike around town or small day hikes where you will encounter rain (no more than 20 lbs packed) then this is a great pack. The extremely durable 600D material and welded seams makes this one of the most durable packs out there. If you want one for actual backpacking in the backcountry, this might not be the best choice. The reason is it lacks an adequate waist belt which is needed for long distance hikes. More than 5 miles and carrying 25+lbs you will really start feeling it in your shoulders. It does come with a 1" webbing waste belt, but this is to help stabilize it, not to carry the weight. The thing I love about this pack is it's easy entry. The roll top closure and clasp make this one of the best packs for quick access. I also love that once you put something in it, whether it's a computer and/or other electronic devices, books, papers, clothes, or whatever, it is going to stay dry. The stiffener at the top makes it really easy to roll and it will soon become one of your favorite packs. I also like the fact that it doesn't look like other packs out there. It really stands out in a good way. The quality and construction are top notch and it has a very high-end feel. It's also entirely made in the USA (Seattle, WA). It is an awesome pack!