I share the parent's sentiment; finding easy access to good weather data is hard.
Do you want your side project to be an experience in learning how to parse obscure formats and coordinating obsolete dependencies, or HTTP GET some JSON and immediately do something with the data?
They're literally giving you all of the data in a plaintext format with documentation, and you're still complaining?
Sure, having everything handed to you on a silver platter is nice, but why should they do your project for you?
You know what you get with a format that's not "modern"? A huge, mature set of tooling that works. For instance, without trying because just responding to this whinging is barely worth the wear on my keyboard, I'd be disappointed if OS X wouldn't cheerily open the file, and unarchive it into the original directory structure simply by typing "open weather_data.txt.gz" from a terminal window. In other words, one could script it. I'd show you how, but holding your hand leaves me with only one hand for typing.
> HTTP GET some JSON and immediately do something with the data
Well, that's the magic of JSON: any code I write just wondrously knows what to do it without me telling it how to parse it. How can poor ol' ASCII text possibly compete?
wget -O - http://cdiac.ornl.gov/ftp/ushcn_daily/state01_AL.txt.gz | gunzip -c | in2csv -s schema.txt | csvjson
Why can't we ask for nice things, even if they are "free"?
How are you going to get a kid interested in programming historical weather analysis when he's got to figure out how to configure an entire stack just to query your dataset. If you really want my opinion, this should be an AI problem, not yet another tedious MVC application.
Furthermore, when I jump into projects, I am most definitely appreciative that there is a responsive system on the other end, no matter how much I'm getting paid. I'm not some noob and yes I have imported gigabytes of minimally-structured data into my own applications, but I don't want to have to do that every time. Especially just to tinker.
If you're not thinking about how your software development experience can be made quicker, more direct, and less painful, I pity you. Shit on JSON all you want, but I'll take a populated native object and a blinking cursor over FTP'd text files any day.
I'm not sure this particular hill is worth dying for. Remember, text was the universal transport long before JSON was (and probably will be long after).