One of the concerns for Western women travelling to an Islamic country such as Iran is what to wear so that you respect the culture, but also keep cool in the mid-day heat which can reach 90+ degrees at certain times of the year. I did some research and found that loose clothing which hides the shape or form of your contours reaches your wrists and covers down to your ankles is recommended and is certainly obligatory for those visiting mosques. All this is in addition to a headscarf which must be worn at all times in public places. If however, you turn up at a mosque and you are considered to be inadequately modest, you will be offered a chadoor to wear during your visit. This is quite common for Western vistors and once inside the mosque, you will blend in with everyone else and any feelings of self-consciousness will disappear very quickly.
I took plenty of scarves of all colours with me. It is not necessary to wear black although you will tend to attract attention if you go for the more adventurous designs. If you are fair-haired, or fair-skinned like me, also be prepared to be stared at in an inquisitive, polite way. It may take you a while to get used to but I never felt any malice or distain in those glances; merely curiosity.
Wearing a chadoor properly and for long periods however takes some practice and I quickly found that the best way for a novice to keep cool whilst dressing appropriately was to invest in a manteau. A manteau is a long, button-up coat-dress which can be worn on its own when hot, or over normal clothing when cooler. As it was 90+ degrees at times, I chose a black cotton version which was very simple and easy to wear. Mine cost a mere £9 and was THE bargain of my holiday.
A manteau with headscarf is all you need as long as you cover your ankles with long skirt, trousers, leggings or dark tights/pop-socks. Could it be more simple? Hurrah for the Manteau!