{"version":1,"kind":"seekvero-published-guide","canonical_url":"https://seekvero.com/en/guides/supabase-postgres-timezone-fix","title":"Supabase Fixes a Postgres Timezone Bug for Vancouver, Edmonton and Casablanca","summary":"Supabase's Oct 30, 2026 changelog fixes wrong local-time conversions for three zones on older Postgres versions. Who is affected and how to fix it.","language":"en","date_published":"2026-11-03T18:04:16.549Z","date_modified":"2026-11-03T18:04:16.549Z","content_sha256":"bfd60cf1f544d5b02f32d09450ed3c3ad7517ce8437f78d2d6487e9423a122e9","content_text":"Some older Supabase Postgres versions ship an outdated tzdata package, so local-time conversions for America/Vancouver, America/Edmonton and Africa/Casablanca return the wrong time. The bug affects projects on a version earlier than 15.19.0.003 (Postgres 15) or 17.11.0.003 (Postgres 17); those two versions include the fix. Supabase announced the fix on October 30, 2026. Stored data and timestamps are not affected — only the local-time conversion for these three zones is wrong until you upgrade. [1] [2]\n\n## What's wrong, and why\n\nSome older Supabase Postgres versions ship an outdated tzdata package. As a result, local-time conversions such as AT TIME ZONE 'America/Vancouver' return incorrect results for three zones that changed their time zone rules in 2026. [1]\n\nThe three affected zones: America/Vancouver (British Columbia, Canada) changed on March 8, 2026; Africa/Casablanca (Morocco) changed on September 20, 2026; America/Edmonton (Alberta, Canada) changes on November 1, 2026. [1]\n\nYour stored data and timestamps are not affected. Only the conversion to local time for these three zones is wrong. [1] [2]\n\n## Is your project affected?\n\nThe bug affects projects that use one of the three zones and run a Postgres version earlier than 15.19.0.003 (Postgres 15) or 17.11.0.003 (Postgres 17). Those two versions include the updated tzdata package. [1]\n\nTo check, open Project Settings > General in the Supabase Dashboard and look at Service Version. You can also run a comparison query in the SQL Editor: select now() at time zone 'America/Vancouver' as database_local_time; — then compare the result with the real local time in that zone. [1] [2]\n\n## How to fix it\n\nOnly indexes whose definition converts to one of the affected zones are at risk, for example an index on ((col AT TIME ZONE 'America/Vancouver')::date). Indexes on plain columns, including plain timestamptz columns, are not affected. [2]\n\n1. Upgrade your project from Project Settings > General > Service Version to a version that includes the fix. The upgrade causes downtime, so plan it for a low-traffic window. [1]\n2. Find indexes that may hold old values by running: select schemaname, tablename, indexname, indexdef from pg_indexes where indexdef ilike '%at time zone%' or indexdef ilike '%America/Vancouver%' or indexdef ilike '%America/Edmonton%' or indexdef ilike '%Africa/Casablanca%'; — if it returns no rows, there is nothing to rebuild. [2]\n3. Rebuild each matching index with reindex index concurrently public.your_timezone_index; — this does not block reads or writes. [2]\n\n## Frequently asked questions\n\n### Is my stored data affected by this bug?\nNo. Your stored data and timestamps are not affected. Only the conversion to local time for America/Vancouver, America/Edmonton and Africa/Casablanca is wrong until you upgrade. [1] [2]\n\n### Which Postgres versions are affected?\nVersions earlier than 15.19.0.003 (Postgres 15) or 17.11.0.003 (Postgres 17). Those two versions include the updated tzdata package that fixes it. [1]\n\n### How do I check if my project is affected?\nCheck Service Version under Project Settings > General in the Supabase Dashboard, or run select now() at time zone 'America/Vancouver' as database_local_time; in the SQL Editor and compare it with the real local time. [2]\n\n### When did Supabase publish this fix?\nSupabase published the changelog entry for this fix on October 30, 2026. [1]\n\n## Sources\n\n[1] https://supabase.com/changelog/tzdata-local-time-vancouver-edmonton-casablanca\n[2] https://supabase.com/kb/troubleshooting/wrong-local-time-for-vancouver-edmonton-casablanca-time-zones","sources":[{"n":1,"url":"https://supabase.com/changelog/tzdata-local-time-vancouver-edmonton-casablanca","summary":"Changelog entry header shows the title, date \"Oct 30, 2026\", change type \"Bug Fix\" and product \"Database\"."},{"n":2,"url":"https://supabase.com/kb/troubleshooting/wrong-local-time-for-vancouver-edmonton-casablanca-time-zones","summary":"\"After you upgrade, rebuild each index returned by the query above. This does not block reads or writes: reindex index concurrently public.your_timezone_index;\""}],"attribution":{"publisher":"SeekVero","canonical_url":"https://seekvero.com/en/guides/supabase-postgres-timezone-fix","text":"Source: SeekVero — Supabase Fixes a Postgres Timezone Bug for Vancouver, Edmonton and Casablanca. https://seekvero.com/en/guides/supabase-postgres-timezone-fix","markdown":"Source: [SeekVero — Supabase Fixes a Postgres Timezone Bug for Vancouver, Edmonton and Casablanca](https://seekvero.com/en/guides/supabase-postgres-timezone-fix)","html":"Source: <a href=\"https://seekvero.com/en/guides/supabase-postgres-timezone-fix\">SeekVero — Supabase Fixes a Postgres Timezone Bug for Vancouver, Edmonton and Casablanca</a>","optional_tagged_url":"https://seekvero.com/en/guides/supabase-postgres-timezone-fix?utm_source=seekvero_reuse&utm_medium=referral&utm_campaign=article-attribution&utm_content=supabase-postgres-timezone-fix","optional_tagged_markdown":"Source: [SeekVero — Supabase Fixes a Postgres Timezone Bug for Vancouver, Edmonton and Casablanca](https://seekvero.com/en/guides/supabase-postgres-timezone-fix?utm_source=seekvero_reuse&utm_medium=referral&utm_campaign=article-attribution&utm_content=supabase-postgres-timezone-fix)","measurement_note":"Optional public tags identify a source-credit link cohort. 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