Aim: To investigate the effect of surgical starting time and season on the prognosis of octogenarians with colorectal cancer. Patients & methods: A total of 291 patients aged 80 years or above who received elective colectomy for colorectal cancer between January 2007 and December 2018 in the National Cancer Center in China were included. Results: No significant time- or season-dependent difference in overall survival for all clinical stages was found in the study. Comparing perioperative outcomes, the morning group had a longer operative time than the afternoon group (p = 0.03), but no significant difference was found based on the season of colectomy. Conclusion: These findings provide insights into clinical outcomes for colorectal cancer patients aged more than 80 years.