It's a matter of maximizing surface area. They virtually have the same surfaces area, perhaps in half it would be able to flutter more with any potential wind, but more potential to stick to itself as well. My money is on the ones hung from the ends. Its max surface area without another half interfering with any wind, though its gotta be darn close to the same result really

Hanging from the ends lets the entire face of it on both sides be hit by wind and sun all at once.

Folding in half makes the inside of the folds be in the shade and the one half partly blocks the other half from getting the wind and sun.

Im going with hanging from one end.

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It's not about drying speed, though increased surface area does speed drying, the surface area of a piece of clothing is too small to have a practical effect. From the practical standpoint, it's about how the cloth will be affected by it's position when drying. Cloth will take a "set" as it dries, which you will want to use to your advantage, and avoid an improper set. For example, hanging a shirt by pinning it's tail end will put the greater weight of the shirt at the bottom, which helps decrease (but not necessarily remove) wrinkles by using the weight to help draw the wrinkles out as it dries. Avoid folding in the middle and placing clothing over the line, as it will put a crease mark in it that can be difficult to iron out.

Drying time is much more affected by temperature and humidity levels of the area you live in than position on the line. When I lived in the Southwestern desert, during the summer, by the time I had hung the last of my clothes on the line, I could go back to the first item and remove it, as it had dried. Down here in humid Florida, that is not the case. A more extreme example is hanging wet clothes in the winter in northern climates. The clothes will still dry even though they will freeze first, but it will take much longer.

Really the best position to put it is the one that maximizes the surface area available, hence it dries faster, now which position is depended on on what you are hanging, usually just spreading them as much will have as much effect on drying them

If all you want to do is make the clothes dry faster, you are much better off hanging them by one end than hanging them by middle, draped over the line.

A typical garment, if we ignore things like pockets, has four surfaces. If you imagine wearing a t-shirt, you have the inside and outside surface of the front portion of the shirt, and you have the inside and outside surface of the back portion of the shirt.

If you hang an article of clothing by an end, the outside surfaces of both the front and the back of the garment are exposed to the atmosphere. The inside surfaces of the front and the back of the garment are, of course, in contact with each other. So of the total surface area of the garment, counting both inside and outside, half of it is exposed to the atmosphere and half of it is in contact with other wet material.

If you hang an article of clothing over the clothes line at roughly its midpoint (let's say with the front of the garment on the exterior), the only surface that is exposed to the atmosphere is the exterior side of the front of the garment. Because of the fold, the exterior side of the back part of the garment is now in contact with itself. So you've lost half of the total surface area exposed to the atmosphere. This will obviously mean that the garment will dry significantly more slowly.

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If you're using multiple parallel lines (or a clothes drying rack), drape pieces of clothing so that each piece goes up and over one line, across, and then down over the adjacent line, leaving space in between.

That trades space for speed, so don't do it for everything; just do it for the stuff you need relatively quickly.

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