I can confirm those studies are correct to me personally. When the weather is hot, even if it's not too hot, it's really hard for me to get productive. And pushing myself to be productive can be a pain, though, most of the times I have to do it anyway. So, good for you for not making that same mistake by setting up your working environment to be comfortable. But when it's cloudy, or cold, or even better: raining, it can boost my artistic productivity.