Prevailing winds are from the west, that is, from the sea, and so the rains tend to come from a westerly direction. The rainclouds drop most of their moisture on the western slopes of the hills, with a considerably decreased amount falling on the eastern slopes. In general the rainfall tends to become less from west to east, although this may be counteracted by the fact that rainfall may increase with altitude. The average annual rainfall near Acco on the coast and at Jerusalem up in the hills is about 24–6 inches (61–6 cm). This is similar to the annual rainfall in the London area (23.5 inches, 60 cm), Edinburgh (25 inches, 64 cm) or Victoria, British Columbia (27 inches, 69 cm). The important difference is that the rains do not fall throughout the year but are restricted to the ‘winter’; the summers are rainless. Inland, on the plain north of Megiddo, where the elevation is slight, annual rainfall is a little less than 16 inches (about 40 cm). The high hills of Upper Galilee receive about 47 inches (120 cm) of rain (compare New York City with about 42 inches or 107 cm). South of Hebron only about 12 inches (30.5 cm) falls. This illustrates how in general there is tendency for the rainfall to decrease as one goes from north to south.
The biblical text refers to early (or former) rains and later rains (see for example Deut. 11: 14 ). The early rains come in the autumn and with them begins the agricultural year because ploughing can now be done on the rain‐softened ground. It is quite understandable that the Israelites had an autumnal calendar; as in the modern Jewish calendar, the New Year occurred in the autumn, near the autumnal equinox. The heaviest rainfall occurs from December to March. The later or spring rains are those of April and May, so important for the ripening of the crops (see Prov. 16: 15; Jer. 3: 3; Amos 4: 7 ). Proverbs 26: 1 alludes to the problem of rains which come at the wrong time. The verse also mentions snow, which is relatively rare but not unknown in the hills. Frost also occurs from time to time in the winter.