Sounds like a great idea, but we should put some effort into it to get it started.
I already made several comments below the question, but let's make these a proposal.
In order to be able to compare the datasets (Which one is suitable for my purpose?) a set of standardized parameters of the data in the set would help. I suggest additions in the format:
[types of data][period][time resolution][geographic area]
[precipitation, wind speeds, temperatures][1960-current][daily][world]
The question needs to be found. We cannot close past questions as duplicates. I suggest either editing in or commenting on past questions with the remark:
Questions about sources of weather data have been combined into the community wiki question Sources of weather data. Please add further answers over there.
Editing this in would be the most obvious, but IMO that feels a bit like intruding on the OPs intention - then a comment would be better.
Candidate questions for this can be found by searching for keywords like weather, rain, snow, ...
Would we have to mention this meta-question too?
Answers from those questions should be copied here. We can leave a comment under each:
Questions about sources of weather data have now been combined into the community wiki question Sources of weather data. Can you copy your answer over there, [name]? (that leaves the credit with them).
If the original author has not done that in a month, someone else can do it refering to the original answer with attribution:
This answer was originally written by [name]. It was copied to this community wiki question from [here].
The copy should be a community wiki, of course.
Please comment on 1) 2) 3) or add 4)...