These are cirrocumulus clouds. When the clouds in the sky look like this picture, it is called a "mackerel sky" because the clouds look like the scales on a mackerel fish.
Click on image for full size
Courtesy of UCAR Digital Image Library
Cirrocumulus clouds belong to the High
Cloud group (5000-13000m). They are small rounded puffs that usually appear in
long rows. Cirrocumulus are usually white, but sometimes appear gray. Cirrocumulus clouds are the same size or smaller than the width of your littlest finger when you hold up your hand at arm's length.
If these clouds cover a lot of the sky, it is called a "mackerel sky"
because the sky looks like the scales of a fish. Cirrocumulus are usually seen
in the winter time and indicate fair, but cold weather.
You might also be interested in:
The high cloud group consists of Cirrus, Cirrostratus, and Cirrocumulus clouds. High clouds are made of ice crystals due to the cold air in the upper sky. The base of a high cloud above the surface can...more
The Earth travels around the sun one full time per year. During this year, the seasons change depending on the amount of sunlight reaching the surface and the Earth's tilt as it revolves around the sun....more
Cirrostratus clouds belong to the High Cloud (5000-13000m) group. They are sheetlike thin clouds that usually cover the entire sky. The sun or moon can shine through cirrostratus clouds . Sometimes, the...more
Weather fronts can cause clouds to form. Fronts occur when two large masses of air collide at the Earth's surface. Warm fronts produce clouds when warm air replaces cold air by sliding above it. Many different...more
Altocumulus clouds are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part of the cloud darker than the other. Altocumulus clouds usually form in groups and are about...more
Altostratus belong to the Middle Cloud group (2000-7000m up). An altostratus cloud usually covers the whole sky and has a gray or blue-gray appearance. The sun or moon may shine through an altostratus...more
Cirrocumulus clouds belong to the High Cloud group (5000-13000m). They are small rounded puffs that usually appear in long rows. Cirrocumulus are usually white, but sometimes appear gray. Cirrocumulus...more