Observations are presented on the statistical distribution of temperature fluctuations on horizontal scales from 10 cm to 1 km in the seasonal thermocline. This range is especially interesting because it includes internal wave processes on the long end and it approaches microscale processes on the short end. A measure of the activity level is computed as the variance of horizontal gradients of temperature or conductivity normalized by the square of the mean vertical gradient, essentially a pseudo Cox number, in eight wavelength bands across this range of scales. The activity levels are found to be distributed approximately lognormally in these bands, with the mean level increasing with decreasing wavelength in conformance with previously published temperature and displacement spectra. Root-mean-square slopes inferred from the mean activity level are found to be slightly less than 1% for wavelengths longer than 300 m and increase only slightly on shorter scales until a wavelength of 2 to 3 m, where they increase sharply. The variance also increases significantly near 3 m and is significantly greater near the peak density gradient under the base of the mixed layer than deeper in the seasonal thermocline. Both horizontal and vertical correlation lengths of the log of activity level are calculated, providing estimates of ''patch'' sizes which are about 100 m long and about 1 m high for the shortest wavelengths. These correlation lengths are used with local estimates of the variance of activity level to conclude that there is significant inhomogeneity and/or nonstationarity in the data set. ¿ American Geophysical Union 1992