Cloud cover such as the Amazon Rainforest and some others are almost always clear such as the Sahara Desert. Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of measurement of the cloud cover. The cloud cover is correlated to the sunshine duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This
Vietnamese units of measurement Vietnamese units of measurement Vietnamese units of measurement () are the largely decimal units of measurement traditionally used in Vietnam until metrication. The base unit of length is the "thước" (chữ Nôm: 𡱩; lit. "ruler") or "xích" (). Some of the traditional unit names have been repurposed for metric units, such as "thước" for the metre, while other traditional names remain in translations of imperial units, such as "dặm Anh" for the English mile. Originally, many "thước" of varying lengths were in use in Vietnam, each used for different purposes. According to Hoàng Phê (1988), the traditional system of units