In Tanganyika, in lat. 4° S., long. 29° E. (E.F., 2,670, E.M., 813), the mean annual temperature is 76·7° F. (24·8° C.), the mean of the hottest month (of October) being 81·7° F. (27·6° C.), and of the coolest, in December, 74·2° F. (23·4° C.), the extremes being 90·7° and 64·4° F. (32·6° and 18° C.). The rains occur in April and May and November and December, while from June to September is dry, the annual rainfall being 50 ins. (1,270 mm.).
Further south, Zoruba, in Nyassaland, has a total rainfall of 62·23 ins. (1,581 mm.), falling on 144 days in the year, but should otherwise be a pleasant climate, as the relative humidity is usually low.
| Zoruba. Lat. 16° S. E.F., 1800. E.M., 548. | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Month | Temperature at 7 a.m. | Mean Monthly Maxima | Mean Monthly Minima | Relative Humidity at 2 p.m. | Rainfall | Number of Rainy Days | ||||
| F. | C. | F. | C. | F. | C. | Ins. | Mm. | |||
| January | 69·8 | 21 | 81·2 | 27·3 | 65·9 | 18·9 | 78 | 11·62 | 295 | 27 |
| February | 66·7 | 19·3 | 77·6 | 25·3 | 63·7 | 17·6 | 74 | 15·42 | 391 | 20 |
| March | 66·7 | 19·3 | 78·9 | 26·1 | 64·7 | 18·2 | 90 | 7·60 | 193 | 23 |
| April | 64·4 | 18·1 | 75·4 | 24·2 | 61·7 | 16·5 | 76 | 11·74 | 298·5 | 14 |
| May | 61·1 | 16·1 | 76·9 | 25·0 | 58·0 | 14·4 | 65 | 0·37 | 9·0 | 7 |
| June | 57·1 | 13·9 | 68·4 | 20·3 | 54·4 | 12·5 | 66 | 2·55 | 64·8 | 12 |
| July | 55·0 | 12·8 | 68·8 | 20·5 | 52·9 | 11·7 | 65 | 0·87 | 21·8 | 6 |
| August | 55·4 | 13·1 | 71·4 | 21·9 | 52·3 | 11·3 | 51 | 0·15 | 3·8 | 4 |
| September | 62·7 | 17·0 | 79·0 | 26·1 | 58·1 | 14·4 | 48 | 1·80 | 45·7 | 4 |
| October | 68·5 | 20·3 | 85·4 | 29·7 | 62·6 | 16·9 | 53 | ·95 | 24·1 | 4 |
| November | 72·0 | 22·2 | 88·3 | 31·3 | 67·1 | 19·4 | 53 | ·35 | 8·9 | 4 |
| December | 73·2 | 23·0 | 83·6 | 28·6 | 65·6 | 18·6 | 66 | 8·81 | 223·8 | 19 |
The capital, Blantyre, at E.F., 3,280, E.M., 1,000, is naturally even cooler, but has a heavier rainfall, distributed as below:—
| Jan. | Feb. | Mar. | Apl. | May | June | July | Aug. | Sept. | Oct. | Nov. | Dec. | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ins. | 19·51 | 17·60 | 14·48 | 13·77 | 4·05 | 3·28 | 3·34 | 1·56 | 1·83 | 4·13 | 5·54 | 15·35 |
| Mm. | 484·6 | 447 | 368 | 349·5 | 102·9 | 83·7 | 85·1 | 39·5 | 46·8 | 105·3 | 140 | 390 |
The Congo Basin.
—The climate of the basin of the Congo is notoriously unhealthy, especially as the portion as yet opened up seldom extends far beyond the low malarious banks of the great river and its tributaries. The warmest month is February or March, and the coldest July or August.
Hann gives the following table of the temperatures of the following stations:—
| Station | Latitude | Mean Annual Temperature | Mean Temperature of Warmest Month | Mean Temperature of Coldest Month | ||||
|---|---|---|---|---|---|---|---|---|
| F. | C. | F. | C. | F. | C. | |||
| Luluaberg | 5·9 | ° S. | 81·3 | 27·4 | 81·7 | 27·6 | 80·8 | 27·1 |
| Congo, mouth of | 6·0 | ° S. | 76·8 | 24·9 | 80·5 | 26·9 | 70·9 | 21·6 |
| Vivi | 5·7 | ° S. | 77·2 | 25·1 | 80·5 | 26·9 | 71·7 | 22·0 |
| San Salvador | 6·3 | ° S. | 77·9 | 25·5 | 81·0 | 27·2 | 72·8 | 22·7 |
| Brazzaville | 4·3 | ° S. | 81·2 | 27·3 | 84·7 | 29·3 | 75·2 | 24·0 |
| Bolobo | 2·2 | ° S. | 80·5 | 26·9 | 81·5 | 27·5 | 79·4 | 26·3 |
| Equatorville | 0·0 | 79·1 | 26·2 | 80·6 | 27·0 | 78·2 | 25·7 | |
| Bangala | 1·5 | ° N. | 78·9 | 26·0 | 80·8 | 27·1 | 77·7 | 25·4 |
These are typical equatorial climates, the greatest range between the means of the coldest and hottest months being at most 9·5° F. (5·3° C.), while in one case the range is less than one degree of the Fahrenheit scale, and though the temperatures are in no case excessive, the dampness of the atmosphere makes the heat of a very trying character, especially in certain localities, as at Stanley’s Pool, where during August and September there are certain peculiar night-winds which, not unfrequently, are the cause of cases of heat apoplexy, and this although the highest temperature recorded is but 97°, at Brazzaville.