Hourly counts of stable flies feeding on cattle, and concurrent weather measurements, were used to describe daily feeding patterns and to estimate effects of temperature, radiation, wind, and humidity on feeding responses. Daily feeding patterns in Nebraska were consistently unimodal, with maximum rates occurring at midday. In the prevailing summer conditions, flies appeared to engorge once or less per day, and feeding rates were partially determined by time, regardless of weather. Several methods were developed for estimating daily cumulative feeding rates for unimodal patterns from one or more independent counts of feeding flies. Consideration of time improved precision of estimates by a factor of four. Effects of weather were estimated by a function,H, which expressed feeding rates in proportion to numbers of flies that had not previously fed during the day. Time was always the most important variable and increasedHexponentially. Increasing temperature independently increasedHto a maximum at about 33.2°C, with 10 and 50% of the maximum at 19.7 and 25.8°C, respectively. Increasing radiation and decreasing relative humidity both reduced feeding responses, and because of their correlations with temperature, decreased relative feeding rates at high temperatures and increased them at low temperatures. Wind interacted with radiation and relative humidity so that the more drying combinations of these variables always decreased relative feeding activity.