We used the Hubble Space Telescope to make wind speed and wind direction measurements of the Martian atmosphere during early northern summer (Ls=97¿). Our strategy utilized a series of near-UV images with optimal temporal sampling to track observable cloud features and to determine the direction and speed of cloud motion. Several techniques were used to identify similar features between images, including Fourier transform and cross-correlation. In these measurements, which span 19--75 ¿N lat and 319 ¿E to 135 ¿W lon, we find average wind speeds of 26.2¿10.1 m/s and a range of wind directions from 51¿ to 162¿ with an average error of ¿23¿. ¿ 1998 American Geophysical Union