Python Method Builds Correct New York Day Boundaries Across DST Transitions

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A DEV Community tutorial explains that a local calendar day in America/New_York does not always last 24 hours, so adding 24 hours to a UTC start can misplace events. The approach builds local midnights for adjacent dates, converts them to UTC, and compares event instants using a half-open interval. The example Python code is scoped to dates from 2010 through 2030 and includes unit tests. Tests reportedly confirm that the November 1, 2026 fallback day spans 25 elapsed hours and the March 8 spring-forward day spans 23 hours. The article also notes that a dashboard's read time is an observation instant rather than the event time.

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Walk-Forward Testing Explained: Two Versions With Different Rigor

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

Running Apps Across Regions: Routing, Databases, and Failover for Stateful Workloads

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