When we say that it’s a nice day, we usually mean that it is warm and sunny. I guess this makes sense since having a rainy day limits what you can do. However I think that there is more optimal weather than this, such as when it is cloudy and cool, with a nice warm breeze from the south. You can keep all your “nice days” full of blinding brightness and road glare and I will enjoy the cloudy days.
On the other hand, a lot of people also say how much they enjoy rainy days. They like being indoors while it’s raining, if they had to be outside for more than 30 minutes while it’s raining they would no longer like rainy days.