CLIMATE. 21 
In St. Louis, the winter months rarely have a day which is 
really comfortable in the open air; while at least half the sea- 
son is so in San Francisco, the sky being clear, the sun warm, 
and the breezes gentle, so that the weather bears a strong re- 
semblance in temperature to the Indian summer in the upper 
Mississippi basin. Our coldest winter days, at noon, are as 
warm as the warmest in Philadelphia. . 
On the other hand, the summers are cool or cold. In No- 
vember, 1854, the lowest figure reached by the thermometer 
in San Francisco, was 47°, while in July of the same year it 
was at 46°—showing that at no time in the former month was it 
so cold as at one time in the latter. The mean temperature of 
July is 57°, twenty-one degrees lower than in Washington 
city. There are not more than a dozen days in the year when 
the thermometer rises above 80°—at which figure heat first 
begins to be oppressive—while in St. Louis and at Washing- 
ton there are in every year from sixty to ninety days that sce 
that height. No matter how warm the day at noon, the even- 
ings and mornings are always cool, and blankets are necessary 
—at least a pair of them—as a bed-covering, every night. 
Although the mean temperature of summer differs little from 
that of winter, yet there are sometimes very warm days, which 
may be succeeded immediately by very cool nights. San Fran- 
cisco never sees more than three hot days in succession. When 
the sun has had an opportunity to rage for so long a period, 
the air in the interior of the state becomes so hot, that it rises 
rapidly ; and the ocean-winds, which must rush to supply the 
place, never fail to bring cool weather to the vicinity of the 
Golden Gate. Thus the mercury has risen (and that was its 
highest) to 97°, and it often falls in July to 46°; and sucha 
change of fifty degrees might occur within twelve hours. The 
average range of the thermometer in July and August is about 
twenty degrees—from 50° to 70°. Yet, as the mornings and 
evenings are invariably cool, and the noons are not always 
warm, “summer clothing” is seldom worn by men, and never 
for twelve consecutive hours. The common custom is, to wear 
