Do you have anything else you could/would rather be doing? If you're planning on applying to a bunch of research-heavy schools, you should definitely do it. Otherwise, it would be better if you find something else (volunteer-oriented) to do that you think you would actually like. It's not too late to be applying to volunteer things right now. One of the best things I've ever done was volunteer in a free health clinic.
You can actually get a lot out of it (research) for yourself, for your application, and for the interviews. I had two summers worth of research experience and it was more than enough to talk about.