From I Love Qatar:
For most women in Qatar and the rest of the Middle East, the abaya is a sign of respect, dignity, modesty and an easy and convenient way to hide the body according to Islamic teachings. It is long and covers the whole body from the neck to the wrists and then down to the feet. It is usually loose and flowing, though some of the newer designs are more form fitting. The abaya is a very common sight in Qatar as well as the other Middle Eastern countries and is also becoming more common in other Muslim countries where woman find it a convenient and comfortable attire to wear over their everyday clothes when they go out of their homes.
It is believed that the abaya, which was also used by women in the pre-Islamic era, was originally worn to protect the body from heat and sand, to avoid direct exposure to the sun, to stay cool in the summer heat, and as a way to protect them from the winds in winter. It still is! It was also, in ancient times, considered a suitable attire and did not hinder women’s everyday chores round the house.
The abaya is complemented with a headscarf called a Shayla or hijab. This is a scarf that’s tied around the head so no hair is visible. Some women also wear a niqab, which covers both the head and the face. It’s mostly a matter of personal choice or traditions.
read more here @ I Love Qatar