AbstractHeat stress can affect milk production in several ways. We here quantify overall farm‐level heat effects on annual milk revenues, veterinary expenses, and feed purchases in Swiss agriculture. We combine farm‐level accountancy panel data from 1314 representative Swiss milk producers and covering 13 years with high‐quality weather data in a reduced‐form two‐way fixed effect model. Although we find that Swiss milk producers frequently encounter heat stress, we find no significant heat effects on annual milk revenues, veterinary expenses, or feed purchases. This finding implies that Swiss milk farms are on average robust to current heat exposure.