Touring - Sleeping Bag in Summer?

Does anyone here tour without a sleeping bag in summer weather? I'm riding - again! - from Pittsburgh to DC over a week in August, and I'm wondering if there's a reason to carry the sleeping bag. My tent is a two person Columbia Lost Lake, and I'll carry the foam sleep pad with me, and a travel pillow.

I do not bring one if it is forecast for above 70 degrees.

For summer tours, I forego the bag and carry the pad and a light sheet. I've found that to be sufficient for most nights. Also consider checking the local weather channel forecast (www.weather.com) for your destination right before departure to help you decide whether to take the bag or not. And remember, 65F lying still in a tent early in the morning is going to feel a lot cooler than 65F pumping the pedals.

If the typical lows for an area is only in the mid-50s, I don't take a sleeping bag. Instead, I take a lightweight sheet and perhaps a lightweight, small blanket. When temperatures can typically drop into the 40s or below, then I take a sleeping bag.

It can get pretty chilly in Western Pa even if the average low for August is 60F. You could probably get by if you have some warm clothes to sleep in, but I would take my REI Travel Sack (rated 55+F) if I were doing that ride. At 27 ounces it isn't all that much extra weight.

I have camped without a bag and been cold. It wasn't fun, so be a bit conservative.

If you know it is going to be really warm at night I would skip the bag, but still take a sheet.

I happen to have a light sleeping bag (40º F). Typically I'll start by opening it up and using a part of it; as the temperature drops, I often wind up inside it. It's down, so it packs down very small. I can't think of a reason why I wouldn't bring it.

By the way, FWIW I highly recommend a compressible air mattress (e.g. Thermarest), it compacts far better than foam.