climateyoudaoicibaDictYouDict[climate 词源字典]
climate: [14] The notion underlying climate is of ‘sloping’ or ‘leaning’. It comes, via Old French climat or late Latin clīma (whence English clime [16]), from Greek klīma ‘sloping surface of the earth’, which came ultimately from the same source (the Indo-European base *kli-) as produced English lean. Greek geographers assigned the earth’s surface to various zones according to the angle which their ‘slope’ made with the rays of the sun (originally there were seven of these, ranging from 17 degrees of latitude North to 48 degrees, but later the system was elaborated so that each hemisphere was divided into 24 bands or ‘climates’ of latitude).

This was the sense in which the word passed into Latin, where it broadened out into simply ‘region’, and hence ‘weather associated with a particular area’.
=> ladder, lean[climate etymology, climate origin, 英语词源]
climate (n.)youdaoicibaDictYouDict
late 14c., "horizontal zone of the earth," Scottish, from Old French climat "region, part of the earth," from Latin clima (genitive climatis) "region; slope of the Earth," from Greek klima "region, zone," literally "an inclination, slope," thus "slope of the Earth from equator to pole," from root of klinein "to slope, to lean" (see lean (v.)).

The angle of sun on the slope of the Earth's surface defined the zones assigned by early geographers. Early references in English, however, are in astrology works, as each of the seven (then) climates was held to be under the influence of one of the planets. Shift from "region" to "weather associated with a region" perhaps began in Middle English, certainly by c. 1600.