Storms and hurricanes are not unknown in Pennsylvania. They occur once in four or five years, but they are most frequent and destructive in the autumn. They are generally accompanied by rain. Trees are torn up by the roots, and the rivers and creeks are sometimes swelled so suddenly as to do considerable damage to the adjoining farms. The wind, during these storms, generally blows from the south-east and south-west. In the storms which occurred in September, 1769, and in the same month of the year 1785, the wind veered round contrary to its usual course, and blew from the north.

After what has been said, the character of the climate of Pennsylvania may be summed up in a few words. There are no two successive years alike. Even the same successive seasons and months differ from each other every year. Perhaps there is but one steady trait in the character of our climate, and that is, it is uniformly variable.

To furnish the reader with a succinct view of the weather in Pennsylvania, that includes all the articles that have been mentioned, I shall here sub-join a table containing the result of meteorological observations made near the river Schuylkill, for one year, in the neighbourhood of Philadelphia, by an ingenious French gentleman, Mr. Legeaux, who divides his time between rural employments, and useful philosophical pursuits. This table is extracted from the Columbian Magazine, for February, 1788. The height of Spring-Mill above the city of Philadelphia, is supposed to be about 70 feet.

METEOROLOGICAL OBSERVATIONS, made at Spring-mill, 13 miles NNW of Philadelphia. Result of the year 1787.
MONTH.THERMOMETER.BAROMETER.PREVAILING
WIND.		DAYSWATERWEATHER.
of
Fahrenheit,
mean degree		de
Reaumur,
degrés moyens		mean heightof
aur. bor.		of
rain.		of
thunder.		of
snow.		of
tempest.		of RAIN and SNOW.
D.1⁄16OD.1⁄10Oin.pts.1⁄16in.pts.1⁄16
January351 14 29 9 9Variable still 714 31010Fair, still, cold, and snow.
February338 8 29 9 9NE 3 323 7 3Fair, overcast.
March451 58 29 9 7W 6 3 2 4 2Fair, windy.
April543 99 29 9 6Still, SW 32311 213Fair, and very dry.
May612 13 29 9 2Still, WSW1146 2411 4Foggy, cold, and wet.
June707 172 29 8 2WNW 91 110 4Very fair & growing weather.
July722 179 29 910WWSW var.1 52 3 111Fair, and overcast.
August745 189 2910 6W 114 15 2 3Very fair, and cloudy.
September647 145 2910 4WNW 61 12 7 8Fair weather.
October511 85 2911 9WNW vari.1 4 710Foggy, fair, and dry weather.
November451 58 2911 1Still, vari.1 5 2 610Very fair.
December34 9 29 7 7WNW 11 9 Very fair, and very dry.
RESULT.10 Feb. greatest
D. of cold.		10 Feb. D. du plus.
gr. froid.		8 Mar. greatest
elevation.		WNW4731712932814TEMPERATURE
of
the year 1787.
Very fair, dry, abundant in
every thing, and healthy.
5 12 0 30 10
3 July greatest
D. of heat.		3 July plus G. D.
de chaud.		2 Feb. least
elevation.
961 28 5 29
Variation.Variation.Variation.
911 40 5 1 10
Temperature.Temperature.Temperature.
535 9 6 20 9 9

It is worthy of notice, how near the mean heat of the year, and of the month of April, in two successive years, are to each other in the same place. The mean heat of April, 1787, was 54°3, that of April, 1788, was 52°2. By the table of the mean heat of each month in the year, it appears that the mean heat of 1787 was 53°5 at Spring-Mill.

The following accounts of the climates of Pekin and Madrid, which lie within a few minutes of the same latitude as Philadelphia, may serve to show how much climates are altered by local and relative circumstances. The account of the temperature of the air at Pekin will serve further to show, that with all the advantages of the highest degrees of cultivation which have taken place in China, the winters are colder, and the summers warmer there than in Pennsylvania, principally from a cause which will probably operate upon the winters of Pennsylvania for many centuries to come, viz. the vicinity of an uncultivated north-west country.

“Pekin, lat. 39° 54′, long. 116° 29′ W.

By five years observations, its annual mean temperature was found to be 55° 5′.