This is what google reports as time on site: 00:15:42
is this 15 minutes or seconds?
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My bounce rate is 39% would that be good?
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What would be a good bounce rate for lets say 250-500 unique visits a day?
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Revjoe, the bounce rate is pretty good and no need to worry.

ya 39% bounce rate is good but if the site has high bounce rate it not means the has not good do just work your bounce rate is good

For me the bounce rate is high, because I have always had bounce rate below 15% for my site.

Revjoe,

Keep in mind that bounce rate is heavily dependent on industry. Also, this metric should be evaluated in conjunction with other factors such as the structure of your site. For instance a blog with one page may have a very high bounce rate but it could still have very engaging content and a high number of returning visitors. In general, numbers around 20-30% are acceptable. Obviously the lower the better but there should always be some kind of rate even if it is very low (i.e. people get distracted and leave the site, they get to your site by mistake, they close a browser and open the site again in another browser, etc). So its hard to say if your bounce rate is good or not because we don’t know what your site is about or how it is built. You also want to be sure you are excluding traffic that will skew your data (your own machine for example).

There are some good answers here as well,

What is a really great bounce rate for a product or service site? What does Good look like? | SEOmoz Q&A

Hope that answers your question,

Shawn