This question is for a Windy employee:
How much data space is needed to hold historical data? What is the size of the database need to be to hold all historical data? Couple of Terrabytes? Petabytes?
Their are very effective and cheap cloud storage solutions like Azure, AWS and Google. For example for 10 TB of hot data storage, it would typically cost around $300/month.
Since I'm sure you get 10's of thousands of visitors each month, Windy could run a donation drive like Wikipedia does so that it can collect money to spend on Storage and hosting of this beautiful webapp! This would be much better than implementing ugly advertising banners on the site to generate revenue to pay for storage.
I'm sure there are many people here that would donate and would get their universities and/or workplace to donate so that they can have access to this data.