The lightweight plays an important role in the silk bedding sets. In the hottest summer days, nobody wants to have a heavy sheet that is easy to hold the moisture and heat.
If you see a floor model, you should feel the sheets by yourself. Lift them up and rub them between your fingers. If the store has no examples, you could open the package. Remember that silk sheets that keep you cool should feel light and airy. Speaking of breathable properties, it is as important as light weight.
The method to measure the breathability is also easy. You could place your mouth over the sateen sheet sets with your hand on the other side. Blow air through the fabric to determine how much air escapes through to your hand. The more air you feel, the better the breathability is.