Because its so hard to find a true session beer in the US, most of the session beers I drink are served at cellar temp in the UK.
Since there are practically zero session beers in U.S. "craft" brewing, I tend to drink them at the UK cellar temps I find them in.
11 degrees c, which is 51.8F, not 51.7F, not 51.9F BUT 51.8F AND IF YOU DON'T SERVE IT AT EXACTLY THAT TEMPERATURE YOU WILL LOSE THE ABILITY TO TASTE.
Honestly there's not many true session beers around here, but when i'm over in the UK i usually drink them at cellar temp
I left a Daytime six-pack in my truck while golfing on Sunday, and came back and pounded a few that were certainly above 51.8 degrees Fahrenheit. Probably closer to 75-80. I don't know if it's the lack of a malt backbone that allowed the beer to not suck, but...it didn't suck.