LOOKING DOWN ON A SEA OF FOG FROM MT. TAMALPAIS, CALIFORNIA
Cold waves are the rapid and severe falls in temperature that sometimes occur in winter, especially at the front of an anticyclone. Warnings of these occurrences, issued by the Weather Bureau twenty-four to thirty-six hours in advance, often result in the saving of millions of dollars' worth of merchandise susceptible to damage by freezing.
Frosts in the spring and autumn are also predicted with great success, to the immense advantage of farmers, market-gardeners, and horticulturists. The practice of smudging or heating orchards, now so widespread, is usually carried on under the advice of the Weather Bureau, which gives prompt notice to the orchardist when such precautions are in order. The bureau publishes charts showing the average and extreme dates of the last frost in spring and the first frost in autumn for all parts of the country.
A fog is a cloud resting on the surface of the earth. In the United States fog is commonest along the northern and middle parts of the Atlantic and Pacific Coasts. In the interior of the country, especially the western part, it is of rare occurrence, the average number of days a year with fog being less than ten.
Lastly—weather fallacies are rife. Indian summer is merely a type of mild, hazy, heavenly weather that prevails intermittently during our long American autumns. The equinoctial storm is a myth; the climate has not "changed" anywhere within the span of a human lifetime (one year differs from another, but there is no progressive or permanent change); and the moon has nothing whatever to do with THE WEATHER.
[A] See "Brief List of Meteorological Textbooks and Reference Books," 3d ed., by C. Fitzhugh Talman. For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents.
SUPPLEMENTARY READING
| CLIMATE AND WEATHER | By H. N. Dickson |
| AMERICAN WEATHER | By A. W. Greely |
| WEATHER SCIENCE | By R. G. K. Lempfert |
| SOME FACTS ABOUT THE WEATHER Second edition. | By W. Marriott |
| METEOROLOGY The latest general textbook on the subject in English. | By W. I. Milham |
| FORECASTING WEATHER | By W. N. Shaw |
| ELEMENTARY METEOROLOGY | By F. Waldo |
Consult also the numerous publications of the United States Weather Bureau, which will be found in most public libraries.