The Scientific American thus speaks of the uses of climatic data:

Christmas in Many Climes. A general idea of the diversification of climate may be gathered from a description of the weather of some particular day of the year as it exists in many different parts of the world. One is too prone to assume that the weather one has on a given day prevails everywhere. For the moment one does not consider the effect of distance from the equator, proximity to large bodies of water, and elevation above sea level and above the surrounding region. When a holiday or any day of special interest occurs, while the weather cannot make the occasion a success, it can quite effectively destroy all pleasure in the event. When we approach the day of all days in the year when two fifths of the people of the world celebrate the natal day of Christ, interest in the weather increases. The little ones of our clime pray that a mantle of snow may cover the ground, so that dear old Santa Claus may come with his reindeer and sleigh. The boys and girls long for the snow-covered hillsides and the glassy ponds; and even our good old grandmother smiles in anticipation of such a Christmas Day as gladdened her heart when she was a wee tot.

It may be interesting to know under what kind of skies the people of other lands celebrate this international holiday. In the Northern Hemisphere places near the same latitude may have weather conditions greatly at variance the one from the other, because of conditions previously explained. It is our winter now; not because the sun is farthest from us, for in five days the earth will reach the time of perihelion in its course around the sun, and be nearer to the central luminary than at any other time of the year, but because the inclination of the earth’s axis causes us to receive the rays of the sun at a lower angle than during any other season and its intensity is reduced. The conditions are reversed to the people of the Southern Hemisphere; they now receive the most direct rays of the sun and have their summer, which is intensified by the nearness of the earth to the sun.

The event that gave origin to our Christmas holiday occurred nearly two thousand years ago in Bethlehem of Judea; and it may be a new idea to us to try to think of the weather that prevailed at that time and the character of the Christmas Day that land may have this year. We know that it was not cold and cloudy on that eventful night so long ago, for the shepherds were feeding their flocks upon the hillsides and the Wise Men of the East beheld a star and followed it. The star shone brightly from the time they left Herod until they reached the place where the Infant lay. We may therefore judge that this part of their journey was made under a clear sky and that the same conditions prevailed at Bethlehem. Weather observations made at Jerusalem, a few miles from Bethlehem, during modern times, show that during December there are less than fourteen cloudy days on the average. The prevailing winds are from the Mediterranean Sea, only thirty miles to the west of Bethlehem, and therefore rarely does the temperature exceed 65° during the day or fall to freezing at night. While there is evidence that the climate is drier now throughout all of the Holy Land than at the birth of Christ, it is highly probable that when He was born the stars were shining brightly and the hills were green and beautiful and the weather smiling its benediction upon the Son of God.

We now will glance at the weather that experience teaches us will probably prevail in some of the principal cities of the world on Christmas Day, and thus have impressed upon us the fact that on any day of the year humanity lives under widely differing weather conditions throughout the world.

In our own country we know that Maine is the home of ice, snow, and chilling blasts, while in California and Florida orange blossoms perfume the temperate air.

In London Christmas is not always bright and comfortable, for on the average twenty-one days in December are cloudy and the temperature ranges from a few degrees below freezing at night to about 50° during the day.

In Paris the weather is about the same as in London. It has the same percentage of cloudiness, and its daily range of temperature is from 32° to 45°, slightly colder than London. The influence of wind direction and the relation of water and land areas to the location of a city are well exemplified in the fact that Paris, farther south than London, has a lower winter temperature. In the United States the coldest winter winds are from the northwest and they also would be so in Western Europe were it not for the fact that they draw from the ocean, whose waters are much warmer in winter than the interior of the continent of Europe. The northeast winds are therefore the coldest that come to Paris and London. In the first case they draw from the cold interior, and in the second case the air in passing to London from the northeast must pass over the North Sea and the extreme temperature of the cold land is somewhat modified by even this comparatively small body of water with the result that the average daily maximum temperature of London for December is five degrees warmer than its neighbor some two hundred miles farther south.

Berlin and Vienna have the same degree of cloudiness, but there the similarity ceases. Berlin, only about one hundred miles from the Baltic Sea on the northeast and about double this distance from the North Sea on the northwest has an average range of but eight degrees between day and night temperatures, while Vienna, deep-set in the interior of a great continent, has a daily range of thirty-seven degrees, the average temperature swinging from 13° to 50° each day during December.

Constantinople was named after the Roman Emperor who made it his capital and who first protected the early Christians from persecution, then became converted and, in the manner of his time, forced others to accept the doctrine at the point of the sword. Here Christianity was first recognized and adopted as a State religion, but since the middle of the fifteenth century Constantinople has been the home of the Sultan of Turkey and the principal city of those who worship Muhammid as the prophet of God instead of Christ. This ancient city, so interwoven in the history of Christianity, has a delightful climate at Christmas time, the daily range being from between a little above freezing and 65° or 70°, with clouds obscuring the sky about one half the time.

Historical Rome has about as many clear days as cloudy ones and the days are pleasant and the nights simply cool.

At Cairo, in the land where Joseph was sold into bondage and where Pharaoh raised him to the highest position in the land next to his own, no more delightful place can the traveler find at Christmas time. Only one day in three is cloudy and the gentle winds are warm and balmy, with a daily range in temperature of 12°.

In Calcutta there is a great amount of sunshine, only one day in five being cloudy, with an average daily minimum temperature of 58° and a maximum of 80°.

Bombay is also sunshiny at this time of the year and excessively hot, with a range each day from 66° to 88°. Here, as at Calcutta, Brahmanism and Buddhism rule instead of Christianity.

China, that enormous empire that believes in the ethical philosophy of Confucius, whose inhabitants have lived for four thousand years with less strife and bloodshed than any other nation, has as great a variety of climate during December in the widely separated parts of its broad domain as has the United States. On any day of the Christmas month some parts of this country are bound in icy chains, while other parts are sweltering in a torrid temperature.

That wonderful Island—Japan—whose people have made such amazing strides in catching up with the most advanced civilization of the Occident, and who never have accepted Christianity, has a most delightful climate during winter, with a large amount of sunshine and moderate temperatures.

The vast Christian nation so long ruled by the Tzar, and now in such deplorable chaos, has a varied climate during December. From temperate conditions in the southern portion of its European possessions it gradually grows colder as one goes northward until a region of great severity is reached. At Petrograd the average night temperature is 6° below zero. At Moscow it is colder, the average of its minimum temperature being 11° below. Two thirds of the time it is cloudy at these two cities.

Verkhoyansk, in the central portion of Siberia, is nearly the coldest place in the world where observations are regularly taken. There Christmas Day may be ushered in with a temperature as low as 75° below zero. For days at a time this extreme cold remains, the warmest part of the day varying but little from the coldest.

In many of the cities of the Southern Hemisphere Christmas Day is likely to be such as will cause the sojourner to long for some cooler region. There it is midsummer, the grass is green and the fruit is on the tree. We of the North could hardly realize that it is December. In the pampas of the Argentine Republic everything is parched. The white stucco walls and the red tile roofs in the cities reflect the intense rays of the sun into the shimmering air. In Rio de Janeiro the days are almost unbearable, the daily temperature rising to 100° and over at midday and seldom falling to 60° at night. Bear in mind that the greater part of the area of South America lies between the equator and 30° south latitude. But wherever in these South American cities one can escape to an elevation of several thousand feet a pleasant temperature may be found.

At Santiago, Chili, it is more comfortable than in Brazil, for the nights are cool, even though the day temperatures rival those of the Argentine Republic. But here the cool mountain tops are almost hanging over the coast cities.

At Cape Town, in the extreme south part of Africa, two days out of three are clear and the daily range of temperature is from 48° to 83°, making fairly pleasant conditions during the Christmas holidays.

At Melbourne, Australia, one half of the days are cloudy, and the temperature is moderate, having a range from 54° to 75°.

Thus we see that the climatological features of the world, not only on Christmas but on any other day of the year, are as varied as the hopes and wishes of man, and whatever his desires or physical necessities may be, a climate may be found under the influence of which he may find pleasure and gain health.

The Hottest and the Coldest Places in the World. It is an innate characteristic of the human race to be interested in the abnormal, whether it be in the achievements of men or in the extremes of natural phenomena. This is especially true with regard to the weather. During periods of extremes of heat or cold the natural inquiry is as to whether there ever has been a period of equal or greater severity. Although suffering intensely there always is a desire to “beat the record.” It therefore may be of interest briefly to refer to the hottest and the coldest places in the world.

North America. One of the most torrid places in the United States is in that remarkable region known as Death Valley. It is located in Southern California. Its name is supposed to be derived from a melancholy tragedy that occurred in 1850, in which every member of a party of emigrants perished in Death Valley from thirst and exhaustion, leaving the bones of themselves and their animals to whiten in the sun. The valley is the bed of an ancient salt sea which existed when the climate was much wetter than now; its soil is largely composed of sand, salt, and borax. The borax deposits are large; at places they form crusts that support the weight of travelers. The length of the valley is seventy-five miles, but it is narrow at the bottom, in places being no more than six miles. One of its remarkable features is that its bottom, in many places, is three hundred feet below the level of the sea, one hundred miles to the west. It is fed by several small streams and innumerable warm springs, the water from which is entirely absorbed by the porous soil, although water may be found by digging down a few feet. The water is unfit for use. It is a desolate and forbidden region, inhabited by gnats, toads, lizards, and snakes. However, the employees of a company engaged in the business of marketing borax spend a portion of each year there.

In 1891 an observer of the U. S. Weather Bureau remained in Death Valley from May to September, during which time he made daily observations of the weather. His experience was a most trying one, drawing heavily upon his physical and mental stamina to complete the period of time that had been set for him. For the entire time of one hundred and fifty-four days less than one half an inch of rain fell. There occurred several days in succession with a temperature of 122°. However, this is not the highest temperature ever recorded in the United States. In July, 1887, at Mammoth Tank, in the Colorado Desert, the temperature reached 128° in the shade, and again, in 1884, 124° was reached at the same place. On July 18, 1891, in Death Valley, the maximum was 120° and the minimum 99°, making an average for all hours of 108.6°. The extremely high temperatures reached in the Colorado Desert, which embraces a portion of Southern California and Arizona, do not vary greatly from those of Death Valley; they are not exceeded anywhere in Central or North America. Such degrees of heat, if experienced for two or three weeks in the more humid regions of the eastern half of the United States, would nearly depopulate the region by the havoc of death.

The lowest temperatures in the United States occur in extreme northern portions of Minnesota, North Dakota, and Montana, where temperatures from 50° to 55° below zero have been recorded. It is interesting to note that in this same region the summer temperatures have risen to readings of from 105° to 108°. Of course this heat is quite different in its effects upon life from the heat of the Gulf or Atlantic coasts. One feels a marked difference between the sun and the shade temperatures in these semi-arid regions. Sunstroke is infrequent and death seldom results from exposure, as it does in the East.

The region of severest cold in North America is found about the Great Bear Lake in the British Northwest Territory, where temperatures of 58° below zero have been recorded.

South America. The hottest portion of South America is in the interior, with extensive systems of mountain ranges along the coast preventing the inward flow of the moist rain-bearing winds from the ocean. In a stretch of country extending from Uruguay northward into the interior of Brazil, the average of the highest temperature of each year for a period of several years is 104°, with individual readings much higher. Except on the top of the mountains, or well up their sides, no severely cold weather occurs in South America, seven eighths of its territory lying between the equator and latitude 30° south.

Africa. In Africa is to be found the hottest region of the world, the great Desert of Sahara, upon whose sands beats down the fierce tropical sun with merciless intensity. Here shade temperatures of 130° are frequently experienced. Only those bred to extreme tropical desert heat can long live under such conditions. In a portion of the desert lying between Egypt and the Red Sea the temperature has been known not to fall below 113° for a period of ten days, while on several nights the lowest temperature reached was 118°, with a practically calm air. Africa lies with about one half of its immense area on each side of the equator, and the greater part of its territory inside the Tropical Zone. Except in a few isolated cases on high mountains, temperatures as low as zero never are experienced.

Europe. The warmest portion of Europe is in the region round and about the Mediterranean Sea. The coldest places in all Europe are in the western part of Russia and in the northern part of the Scandinavian Peninsula. Here the average of the coldest days of winter is 50° below zero.

Asia. It is difficult to determine in what part of Asia the highest temperature occurs, as data from many parts are meager. It is known however that extremely hot weather prevails in India and Arabia. Siberia, however, experiences the coldest weather to be found anywhere in the world. At Werchojansk, in that country, a temperature of 90.4° below zero was observed in January, 1884, while the average temperature for the whole month was 69.4° below zero.

The coldest weather of the world is not found at the North or the South Pole, as many suppose, but rather at the center of vast continents, far from the modifying influence of oceans.

Australia. In extreme heat the interior of Australia is fairly comparable with northern Africa, Persia, Afghanistan, and northern India, where every year maximum temperatures of 115° occur, and where, at times, an extreme heat of 120° or 125° is experienced in the shade.

We now know that the forceful, dominating peoples come out of the regions where the heat is not so great as to debilitate, nor the cold so fierce as to deaden the mental and the physical faculties; but rather from the region of the thoroughfare of the great circum-polar storm tracks, where there are frequent changes of weather from sunshine to clouds, and where there is a fairly wide difference in temperature between night and day and between winter and summer. For the best coördination of the mental and the physical faculties, so as to produce the most efficient composite of man, the temperature should range between 45° and 50° at night and between 65° and 70° during the day, with about sixty-five to seventy per cent. of relative humidity. Some day we will artificially create the exact conditions of temperature and moisture needed for patients in hospitals and sanitaria. Science is persistently seeking means to increase comfort and prolong life.