There seems to be a lot of disagreement about the temperatures and conditions under which the Maillard reaction can occur. Cooking professionals reference all sorts of "minimum temperatures" — I've seen sources say 350°F (175°C), 310°F (155°C), 300°F (150°C), 250°F (120°C), 230°F (110°C), and boiling (212°F/100°C) all given as a minimum. Many sources say it cannot occur in the presence of water.
Previous questions on this forum that have discussed the Maillard reaction have also included statements about temperatures, often in disagreement with each other. (See, for example, here, here, and here.) Many answers and comments on answers also have conflicting information.
It's clear that the Maillard reaction requires proteins and a reducing sugar. It is also clear that it will happen at neutral pH or higher, but acidic conditions will significantly inhibit it.
But what temperatures can it actually occur at? Are there examples of the Maillard reaction occurring at lower temperatures?
(I will offer my own answer, but I would certainly be interested in hearing of other examples and information.)