The answer is no. Sorry.
I took it with me on a bike tour of the northeast, July 27th to August 27th. This summer was plenty warm, not unseasonably cold.
First night, I wore a merino wool midweight baselayer, wool socks, a fleece jacket, and a hat, plus the sleeping bag liner.
I was cold the first night, the second, and the third! The problem was, if I blocked wind with my tent the humidity built up and was really uncomfortable, but the sleeping bag liner did nothing and every breeze ripped right through me.
On Day 4, we were with family and I grabbed a fleece sleeping bag liner with a polyester shell (an ALPS Mountaineering Razor) and then I was warm the whole trip. On the top of one mountain, it got to 40º and I would have not slept a minute if I had not grabbed the fleece bag. There were plenty of nights when I didn't need it and the sleeping bag would have been enough, but there were a LOT more nights when I did need it, at least by morning.
I would be very wary of sleeping bag liners for ANYTHING but cleanliness. They are simply not that warm.
The North Face makes a sleeping bag, the Aleutian 1S 55º, that would be perfect for a summer, and it only costs $70.