Welcome @Surtly, do you already have a working prototype with the sensors you want to have and whatever you are using to log your data? It would probably be worth getting everything working on a battery pack first and figuring out your power requirements before looking into getting solar power working, you might be surprised how long a battery pack might last if you only need infrequent samples, etc.
That being said, there is a popular instructables that I had bookmarked that has some good information on it and could help getting an idea of how much power you could expect, etc.
Either way I encourage you to create a Build Log for your project, I'm sure others would love to see the project develop and there are some smart people here who can really give you some great feedback and advice.
Here's the link to the instructables: