Purpose: This study is aimed at investigating whether inpatient complications and surgical site infections (SSIs) occurred more commonly in patients undergoing total knee arthroplasty (TKA) during the summer season. Materials and Methods: A total of 725 patients who underwent unilateral or bilateral TKA were included in this study. A total of 241 patients (33.2%) underwent TKA between May and August. Our outcomes of interest were the incidence of postoperative complications and length of stay. Results: May–August surgeries were associated with a higher risk of postoperative inpatient complications (p=0.003). May–August surgeries (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.18 to 3.85), postoperative transfusion (OR, 2.46; 95% CI, 1.43 to 4.26), postoperative special care unit stay (OR, 4.68; 95% CI, 1.99 to 11.0) and chronic kidney disease (OR, 3.27; 95% CI, 1.15 to 9.28) were associated with a higher odds of developing inpatient complications. No association was present between summer surgeries and SSIs (p=0.486). Conclusions: The results of this study show that overall complication rates following TKA exhibit a seasonal trend, with a peak during the summer months. These results may have some implication in clinical practice and stricter approaches to hospital guidelines during the summer months.