Datetime Is Tech Debt You Didn't Know You Had

Why This Matters Almost every developer has a datetime story. An appointment showing up an hour late. A report aggregating the wrong day's data. A notification firing at 3am. It works fine in development, ships, and then a user in a different timezone files a bug you can't immediately reproduce. A 2025 empirical study of real-world bugs in open-source software found that 53.6% of datetime bugs are timezone-related , and 27.8% stem specifically from mixing naive and timezone-aware datetime object