I’ve lived for a long time in both Nordic climates (born in Russia, raised in Canada) and southern climates (Thailand, Vietnam, Mexico). I don’t feel absolute temperature affects my happiness levels long term at all.

When it’s a gloomy rainy day, ya I might feel a bit down. But my wife loves those days. She feels cozy. So it’s really subjective.

But long term the baseline changes quickly and I don’t care if it’s winter or summer. I feel equally happy in both conditions.