Animated Cloud Anomaly Loop

Annual cloud anomalies

Cloud anomalies show the departure in the amount of cloud from the long-period average. They tell us whether a place was more cloudy or less cloudy than average. These anomalies are shown in oktas (or eighths) which refers to the amount of sky covered by cloud.

One okta is equal to 12.5% of sky obscured by cloud. Therefore if a particular location shows an anomaly of 2 oktas, it means that 2 eighths (or 25%) more cloud covered the sky for that year compared to the long term average. Conversely if a particular location shows an anomaly of -2 oktas, then 25% less cloud covered the sky for that year compared to the long-period average.

Each image in the loop shows the cloud anomalies in oktas for that year. For example, the first image in the "1960 - 1969" loop shows the annual cloud anomalies for the year 1960, the second image shows the cloud anomalies for 1961, and so on.