Which is your season?

The weather is going getting better and the daylight hours are quickly increasing <em>(or better still: "… the days are getting longer.")</em>.  the time of the daylight is quickly increasing. Simply put, spring is here. With warmer weather and more hours of daylight my mood is getting better too.
I know there are scientific evidences about the relation between mood and weather and, for example, is demonstrated that the light of the sun increases the production of serotonin, the molecule of the happyness, in our body.

<em>(That's a long sentence! Let's try breaking that down a bit.)</em>

I know there is scientific evidence to suggest that mood and weather are related. <em>(In this context you would have evidence for, to suggest or to show something.) </em>For example, it has been shown that exposure to sunlight increases the production of serotonin, the happiness molecule of happiness, in our body. <em>(The phrase "molecule of happiness" isn't really incorrect. It just looks rather unusual and may not convey what you mean. It might imply that when you are happy you produce that molecule. The phrase "happiness molecule" suggests that the molecule causes happiness and I suspect that is what you meant.)</em>

Anyway, I think we are always in relation all all of us are affected by the weather and some people prefer one season to another. there are people who like more one season than another one.
Who doesn't know people someone who hates summer and prefers to stay at home rather than going out under a hot sun? <em>("… in the hot sun." might be better but what you have isn't wrong)</em>
I think anybody everyone has his their favourite season, independently from irrespective of biochemistry reasons. Perhaps related due to their interests, or memories or anything something else.
I'm not sure about don't know which is my favourite season, but I'm sure it's not winter.