Heat stressed dry cows have lower milk yield (MY) in the next lactation. Cooling systems abate the effects of heat stress (HT) during the dry period (DP) and improve performance after calving. The objective of this study was to evaluate the effect of HT during early or late DP on performance. Cows were randomly assigned to treatment based on mature equivalent MY, dried-off 45 d before parturition, and assigned to cooling (shade, fans and soakers; CL) or heat stress (shade; HT). Treatment groups included: HT (HT, n = 20) or cooling (CL, n = 20) during the entire DP, HT first 3 weeks then CL (CLHT, n = 19) or CL first 3 weeks then HT until calving (HTCL, n = 20). During the DP, data were divided into 2 periods: first 3 weeks of the DP (cows were exposed to either HT or CL); and from 3 weeks until calving (after switch). HT increased rectal temperature (RT; HT vs. CL; 39.1 vs 38.8 ± 0.04°C, P < 0.01) and respiration rate (RR; breaths/min; HT vs. CL; 69 vs. 53 ± 1.8 bpm, P < 0.01) during the first 3 weeks of DP. After the switch, cows that were exposed to HT had increased RT versus CL cows (HT, 39.1; HTCL, 38.9; CL, 38.7; CLHT, 39.1 ± 0.05°C, P < 0.01) and increased RR (HT, 64; HTCL, 53; CL, 47; CLHT, 66 ± 2.1 bpm, P < 0.01). During the first 3 weeks, HT reduced DMI (kg/d) versus CL (HT vs. CL; 10.6 vs. 11.8 ± 0.35 kg/d, P = 0.02). However, DMI did not differ after cows were switched (HT, 10.7; HTCL, 11.1; CL, 11.2; CLHT, 10.1 ± 0.55 kg/d, P = 0.45). Heat stress at any time reduced gestation length relative to cooling (HT, 275; HTCL, 274; CL, 277; CLHT, 273 ± 1.2d, P = 0.04). There were no differences in hematocrit, total protein and body weight (BW) change during the DP among treatments, nor did BW or DMI differ after parturition (P > 0.20). Cooling during early or late DP alone only rescued MY in the first 3 weeks of lactation (HT, 26.6; HTCL, 30.7; CL, 32.9; CLHT, 29.7 ± 1.37 kg/d, P = 0.02), whereas CL for the entire period DP increased milk, fat, protein, and lactose yield among treatments (P < 0.05) up to 140 DIM (HT, 37.8; HTCL, 38.3; CL, 42.9; CLHT, 37.8 ± 1.4 kg/d, P = 0.03). Thus, HT at any time during the DP compromises performance of dry cows after calving.