Clothing for a internship at a city radio station

what type of radio station? NPR or pop?

I'd say trousers, decent shoes, and a standard dress shirt in varying colors.

Depending on the station jeans could be sufficient instead of trousers as I have seen a lot of moderators wear those. 

Is it a talk station or a music station? By public radio station, it sounds like it is more formal? I'd say casual business wear (i.e. chinos, dress shirt, tie, sportcoat).

Hey Lorraine. I think I'm uniquely qualified to answer this one, as the host of a web series about menswear and a nationally-syndicated public radio show .

As long as your son is clean, he'll be fine. He should probably consider showing up on the first day in something like business casual (say chinos and a sweater), but that will likely make him the among the most dressed-up people at the station. The likelihood is that the expectation will basically be clean clothes, no ripped jeans.

Edited to add: if it's a classical station, I'd definitely go with business casual. It's still likely to be casual, but a more conservative brand of casual. Journalists, on the whole, are a slovenly lot.

I would say lots of tweed, elbow patches cardigan and a tweed bow tie.

Well, if it were your son coming here and asking what to wear at his internship, I'd suggest he take his cue from what other people there are working. Specifically, what he's seen other interns at the station wearing, or if he hasn't met any other interns, then what those persons just above interns in the "chain of command" are wearing. Presumably, he's been to the radio station prior to accepting an internship offer there, so he would have some idea of how the people there dress. Naturally, he's free to take it up a small step from what they're wearing, but if everyone else is in jeans and sweat shirts, at least he'll know it may not be appropriate to show up for work in a suit and tie. Conversely, if even the other interns wear ties, he shouldn't arrive in baggy shorts and a t-shirt.

But since your son hasn't come here seeking advice, I would tell you - in a friendly, non-confrontational way - that you shouldn't get involved in figuring out what he ought to wear. This is a decision he needs to make for himself. And that if he doesn't care enough to figure out what he ought to be wearing to his internship, maybe - just maybe - you need to have a father-son talk with him not about clothing, but about the proper attitude toward work and career.
--
Michael
(I've seen both WKRP in Cincinnati, and Newsradio, so I actually know quite a lot about how people in radio dress.)

Jeans and tee shirt unless he is greeting important visitors which will be very unlikely. Assuming he has been t interview, what did he see - that would provide a better answer. Could he not surely telephone and ask what people normally wear doing whatever he is about to do? I doubt it will be glamorous.

I figured everyone in talk radio dressed like Dr. Frasier Crane: