









28 REPORT OF THE HARVARD AFRICAN EXPEDITION 
Mount Mount Du #1 Du #1 Du 4 D wy 9 
Month Barclay Barclay Division Division Division | Division 
1925 1926 1927 1928 1929 1929 
seine cies d stele 72 atte: bee 1.88 57 .92 
Debres oa, oes 83 ror AY 18 2.7 3.19 
March........ 5.60 1273 4.06 4.79 8.97 8.14 
3) er 8.04 13.97 7.26 Teal 10.84 9716 
Cy ae 7.43 7.32 10.25 12.20 13.92 7.49 
sIMO.s" 2. ane 26.14 28.30 23.45 25.78 35.86 32.28 
‘| 30.37 19.07 17.67 DAT 21.04 17.71 
Am Sa, PU ae 27.78 2278 15.04 7s 31.28 13.73 
oe 23.76 26.87 26.18 32.98 (#4) 41.73 24.89 
0 CL ie ee ae 15.25 19.56 15.42 Ne 8.75 8.02 
NOY: ¢:. 4.0408 6.38 10.23 6.66 BLO 4.94 6.16 
[Di eee ene 2 ? Nil 192% 1.00 oe: 
Total 152.25 155.83 126.81 159.98 181.07 131.69 
Monthly 
Average 12.69 12.99 10.57 13.33 15.09 10.97 







nized that Americo-Liberians refer commonly to this season as the ‘‘middle 
dries.” In some years, however, such a distinct season as this is hardly per- 
ceptible in the vicinity of the coast. It is not, for example, shown in the figures 
recorded by Taylor for the year 1913, and in one year it rained for twenty-five 
days in July and in another, twenty-nine days. It is well known that the 
heaviest rainfall occurs just to the south of the trough of low pressure, and so 
there often tends to be a well-marked double rainfall maximum in the course of 
the season, — one as the low pressure trough passes north, and the other as it 
returns south. However, during the whole season of the southwest winds, there is 
considerable rainfail. 
Kendrew,' in his studies on the climates west of Lake Chad, speaking of 
the rainy season of the west coast of Africa, says that Sierra Leone and most of 
the Liberian coast have only one maximum, the rainfall increasing steadily 
until August, and then diminishing. This difference from the weather inland, 
in the same altitude, is doubtless due to the strong summer monsoon from the 
southwest meeting the elevated coast. The precipitation is greatest when the 
monsoon is strongest, that is, during the months when the interior is hottest. 
The rains of Liberia are generally of the equatorial type, that is, in very 
heavy showers falling between noon and midnight, and sometimes accompanied 
with thunder and lightning. At times, however, there are steady downpours 
for several days or even for a week. Occasionally actual tornadoes occur. They, 
however, are of a different nature from those which occur, for example, in the 
western United States. In Liberia, they are generally accompanied by exceed- 
ingly heavy rain and lightning, but with less violent wind than in our country. 
They often start in Liberia very suddenly, and last sometimes only a quarter 
of an hour. They are especially frequent at the beginning and at the end of 
the rainy season, sometimes making their appearance after the prevalence of 
more or less unusual heat. 
' Kendrew: “The Climates of the Continents” (1922), p. 33. 
