Interplanetary scintillation observations from 1971 to 1975 show that the average solar wind speed increases away from the solar equator, with a mean gradient of 2.1 km/s per degree of latitude. These results are compared with spacecraft observations over the ¿7¿ attainable in the eciliptic and with those deduced from comet tails. The role of temporal variations, especially those caused by latitude dependent solar wind streams, is emphasized. This points to the need for extensive ecliptic and ground-based observations during an out-of-the-ecliptic spacecraft mission.