Iran is a country with a dress code. The rules are quite simple: for men, no short pants or short sleeve shirts. For women, your head and hair must be covered. You must also wear something loose to cover your body to mid-calf.
So much for the rules: what was interesting was the variations I saw in the streets. For men I did see some guys, mostly young bucks in Tehran, who wore short-sleeve shirts. In fact, Moghadam wore a short sleeve shirt one day and often had his shirt sleeves rolled up, but then he was from Tehran. I wanted to play it conservative so I stuck to long sleeves, only rolling them up in the car. I figured the least I could do was comply with local sensitivities.
For women there are at least two major dress variations. The most conservative women wear the chador made of a loose piece of fabric, usually black. The woman holds it together at the neck and when their hands are full, they use their teeth. It must be hard to keep the thing in place because you see women readjusting them all the time.
Another common form of dress for women is a hood or large scarf that covers the head and shoulders. This is then worn with a long shapeless coat, like a raincoat. I saw the hoods mostly on schoolgirls and they were often white or blue in addition to black. Scarves seemed to be worn by the more fashionable women and often had bright printed patterns.
Tourist women comprise a separate class: the more sensitive will wear the scarves/raincoat, but you also see some, mostly from larger tour groups – Italians I was told – that just wear a cap or hat and some kind of loose coat. These are probably the very same people who complain that there were not received well in Iran.