What do I wear for an interview for a (math) postdoc?

If my talk were on the mathematics of juggling (which exists! I read a book about it once!), then wearing clown gear might make sense.

After buying the suit, as you might expect, I wore it. They made fun of me a bit for this. Apparently the candidate they had up last week wore a suit, and after that they meant to tell me that I didn't need to, but they never got around to it. But I felt a bit more confident wearing a suit, which has to count for something.

I bought a suit. Some of you advised one way, some the other; I figured the risk of being overdressed is less than the risk of being underdressed. Besides, I'm going to be a grownup now, I should have a suit.

to be on the safe side, wear a suit

I was even told by my interviewer in Madison, "Wear jeans tomorrow!" for my second day of the interview. I hadn't brought any jeans. -http://ask.metafilter.com/143725/What-do-I-wear-for-an-interview-for-a-math-postdoc#2057635 I see from your last question that you are traveling to Ithaca, so I'm guessing the interview is at Cornell. My impression from friends in Ithaca is that its academic culture is similar to Madison's.

I am a man and did not wear a suit to interview for postdoc in the natural sciences in the US. I got the position. I vote non-jeans, button shirt, decent shoes. Dress like the person interviewing you (a professor, I assume, and not a dean) will probably dress. You want to say, "I'm one of you; I just haven't joined up yet." If you are working on a job talk last minute, devote orders of magnitude more time and thought to preparing a clear, confident talk rather than your outfit.

Consider this: If you dress casual, what's the worst case scenario? If you dress in a suit, what's the worst case scenario? I'm in humanities, so your mileage may vary, but I wouldn't even consider not wearing a suit. Here's two more ideas. Ask your advisor/mentor at your grad school. Is there a friendly contact in the post-doc department that you could ask?

Wear the suit, especially if you are giving a job talk. The worst you come off as is looking like you really want the job and want to impress people. Not dressing up enough, however, can come across as if you don't care. I just did the postdoc interviews myself and wore a suit, even though no one I interviewed with did, and no one in my department ever does (in fact jeans are the norm around the labs here). I also do undergrad admission interviews as well and while I've never been turned off by someone over dressing for the interview, I have been for those who underdressed. First impressions matter.

I'm in the physical sciences, at a US university, and I say you should not wear a suit. Seriously, we always look at the people in suits like they are very weird or are trying to prove something*. Even if they are there for a jobtalk. As others have mentioned, a suit can make you look like you don't know what science (or math) is about. Not to mention that it could make you uncomfortable! Also -- you are unlikely to be meeting with very-high-ups for a postdoc interview. I'd say go with non-jeans and a button-down shirt. You will look nice, but nobody will notice what you're wearing, and that's what you want. (Note: the cultural rules may vary a lot by country, so be aware!) *Although for some reason chemists seem to wear suits. I have no idea why.