Our ancestors understood the role weather played in growing food. They saw that nature gave ample warning of approaching rain, storms, and frost. The sky is filled with weather indicators, especially cloud formations. For example, “When ye see a cloud rise out of the west, straightway cometh the rain” (Luke 12:54) refers to the fact that weather fronts usually move from west to east.
“Rainbow at night, shepherd’s delight. Rainbow in morning, shepherd’s warning” refers to the same phenomenon. A rainbow seen in the evening to the east is caused by the setting sun shining from the west, indicating fair weather in that direction. A morning rainbow, caused by the rising sun from the east, indicates rain to the west, heading your way.
“If the sun goes pale to bed, ’twill rain tomorrow, it is said” is another saying that involves cloud patterns. High cirrus clouds in the west give the setting sun a veiled look. When appearing as bands or mares’ tails, they signal an approaching storm.
Finally, who among us will argue with “Clear moon, frost soon”? Cloud cover acts like a blanket over the earth, keeping temperatures from dipping as low as they would on a clear night.
The skies are not the only aspect of nature filled with weather signs. Animal and plant behavior also indicates changes. Here belong all the sayings about the thickness and color of an animal’s coat, the bark on a tree, or the skin of a vegetable, such as “When the corn
wears a heavy coat, so must you.” A related saying is “The darker the color of a caterpillar in fall, the harder the winter.”
Certain animals and plants do respond in a consistent way to a change from a high-to a low-pressure system, which often brings rain. This is why a saying such as “When the sheep collect and huddle, tomorrow will become a puddle” is reliable. “The higher the geese, the fairer the weather,” a saying that applies to all migratory birds, also refers to this phenomenon.
Many plants are sensitive to drops in temperature and to high humidity. “When the wild azalea shuts its doors, that’s when winter temperature roars” refers to the fact that azaleas and rhododendrons draw their leaves in when the temperature drops.
Cold weather lore often merges weather phenomena with common sense. Snow, for example, is known as “the poor man’s fertilizer,” which may be because it acts as mulch, protecting plants and keeping nutrients in the soil that rain would otherwise wash away. Frost is “God’s plough” because it breaks up the ground and kills pests.
Going beyond folk wisdom is phenology, the study of the timing of biological events and their relationships to climate and to one another. Such events include bird migration, animal hibernation, and emergence of insects, and the germination and flowering of plants.
Phenologists have found that many plants and insects within the same region or climate pass through the stages of their development in a consistent, unified sequence. The budding of a given plant, for example, may correlate with the hatching of a particular pest insect. Variations in weather from one year to the next affect the timing of such events, but the order in which they occur tends to remain the same.
As a result, it’s possible to foretell when conditions are right for a crop to germinate or an insect to appear by learning to read the various growth stages of indicator plants. You may want to experiment with phenology in your own yard. For example, you could plant a variety of perennials as indicators that will provide a steady succession of blooms throughout a season. Then observe and record the indicators’ growth phases, along with weather data, the appearance of insects or diseases in your garden, and the progress of food crops.
Sooner or later, patterns will emerge. You may notice that daffodils always begin to bloom when the soil becomes warm enough to sow peas
, or that Mexican bean beetle larvae appear at about the same time foxgloves open. You can then use that information in subsequent years to help you decide when to plant peas or when to start hand picking beetle larvae. Your observations may also help you discern if and how the local climate in your area is changing over time.