For the UK, important streetlight (motorways, junctions, etc) are kept on. But the quieter streets and away from junctions are shut off.
It’s done for “climate” reasons but I’m pretty use the root cause is actually just another cost cutting measure.
My county isn’t listed there so there plenty more councils which also do this and arent mentioned.
“Many” is subjective though. So your experience could be valid and my statement still true.
But regardless, energy savings was also one of the cited reasons. So to answer your question: both.
It’s not really any difference to other traditional climate concerns like wind nor rain aside from light being a non-tactile property. But then neither is heat.
I will concede that my interpretation of the term “climate” here might not be correct. I’m not an expert in this field so it’s entirely possible I’ve stretched the definition