Diverticulitis incidence peaks in warmer months, highlighting potential environmental triggers.

• 1.1 million cases across 8 studies show a summer/autumn peak and winter trough, with amplitude variation of 16% to 27%.
• Phase reversal observed between hemispheres confirms this pattern.

Surgeons should consider seasonal trends when making preoperative assessments and advising patients on preventive measures.

• Further research is needed to identify specific modifiable risk factors linked to these patterns.