English Summer Clouds Warn of Approaching Weather Fronts

Old English sayings about summer skies, such as "Mare’s tails and mackerel scales make lofty ships to carry low sails," offer insights into predicting weather changes. These phrases refer to specific cloud formations that can signal the arrival of warm fronts.

Mackerel skies are characterized by cirrocumulus or altocumulus clouds arranged in patchy, regular rows. The cirrocumulus type appears white and wispy, while altocumulus clouds are thicker and grey. A simple distinction is that cirrocumulus clouds are narrower than a finger held at arm's length, whereas altocumulus clouds are approximately three fingers wide.

These cloud types form when warm fronts push moisture to high altitudes. The appearance of mare's tails (cirrus clouds) and mackerel scales (cirrocumulus or altocumulus clouds) suggests that these high-altitude moisture patterns are developing, which often precedes a shift in weather conditions. Observing these formations can provide an early, albeit informal, warning of approaching weather systems.