Cow comfort is a crucial component to maximizing dairy cattle health and productivity. Combating high temperatures is of particular importance to dairy producers located in California’s Central Valley who must ensure their herd remains cool and comfortable to maintain animal wellbeing and productivity. The purpose of this project was to determine differences in heat stress based on cow cooling methods on a California Jersey dairy while also using infrared technology to measure and predict heat stress. Infrared rear udder surface temperatures, digital rectal temperatures and respiration rates were collected on 30 Jersey cows. Fifteen cows from each of 2 different high-producing mature cow pens were selected to obtain measurements during 3 different times: morning in freestalls (8–9:15 AM), mid-morning in the milk barn (9:30–11 AM), and afternoon in freestalls (1:30–2:45 PM). Management and freestall barn design were similar between pens, with the exception of differing cow cooling methods. One pen was provided with soakers only, while the other pen was provided with soakers and fans. Low to high heat stress was observed in the sample of 30 cows throughout the day. The lowest respiration rates, rectal temperatures, and udder temperatures were observed in the milking parlor during the mid-morning, particularly as cows stood in the holding pen for greater lengths of time. Rectal temperatures for cows in Pen 6 (no fans) differed significantly (P = 0.003) from rectal temperatures measured on the same group of cows when in the milk barn. The positive response to the more frequent soaking times of the milk barn cooling system suggests this method may be more effective in reducing the effect of heat stress than either of the freestall cooling systems. Infrared body surface temperature is currently being explored as a potentially dependable and accurate means of quantifying heat stress in cattle (Jones, 1999; Berg et al., 2013). Data indicated a significant correlation (P = 3 ×10⁻⁴) between infrared udder temperatures and digital rectal temperatures, suggesting that infrared thermography is valuable in identifying heat stress.