Reddit reviews Perko R2 Concealed Door Closer PB

I'm thinking that the only option that would not be exposed on the outside is a chain closer. I've not had the pleasure of specifying or installing any of these, but I've seen them on UK fire doors and they seem to work fine, if not as controlled as the traditional hydraulic closer.

Just as an FYI, about 4 years ago I installed a ryobi doorman on a heavily used outside door that gets regularly to -20°F. I did it as a temporary measure thinking it would at least work for the summer, but it is still going strong. It is under a porch-roof, however.