--- title: This Extra Second Keeps Crashing the Internet | daily.dev description: Devices keep time using quartz crystal oscillators that drift up to 20 seconds per month, requiring periodic sync with internet time servers via NTP. The... canonical: https://daily.dev/posts/this-extra-second-keeps-crashing-the-internet-w4qmvu5p4 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: This Extra Second Keeps Crashing the Internet | daily.dev og:description: Devices keep time using quartz crystal oscillators that drift up to 20 seconds per month, requiring periodic sync with internet time servers via NTP. The... og:url: https://daily.dev/posts/this-extra-second-keeps-crashing-the-internet-w4qmvu5p4 og:image: https://api.daily.dev/og/posts/W4qMVu5P4.png og:image:alt: This Extra Second Keeps Crashing the Internet og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # This Extra Second Keeps Crashing the Internet **[Slidebean](https://daily.dev/sources/slidebean)** · 22 min read · 0 upvotes · 0 comments ## Summary Devices keep time using quartz crystal oscillators that drift up to 20 seconds per month, requiring periodic sync with internet time servers via NTP. The hierarchy runs from your device up through Apple/Microsoft servers, GPS satellites with atomic clocks, and ultimately to the BIPM in Paris which averages ~400 atomic clocks across 80 countries to define UTC. The biggest systemic problem is the leap second: because Earth's rotation is irregular, UTC and UT1 (solar time) drift apart, requiring occasional insertion of an extra second. This has repeatedly crashed major systems — Reddit, Cloudflare, Qantas airlines — because software struggles with a clock that ticks 23:59:60. Google's workaround is 'leap smearing,' spreading the extra second across 24 hours. In 2022, the international community voted to abolish leap seconds entirely by 2035, after which UTC and UT1 will drift independently, eventually diverging by an hour around the year 3000. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Ask HN: Are systems ready for the first negative leap second?](https://daily.dev/posts/ask-hn-are-systems-ready-for-the-first-negative-leap-second--whf0jsguw) · Hacker News · 0 upvotes · 0 comments - [Fwd: Bulletin C number 71](https://daily.dev/posts/fwd-bulletin-c-number-71-cirm6ctec) · Hacker News · 0 upvotes · 0 comments - [Time in C\+\+: Additional clocks in C\+\+20](https://daily.dev/posts/time-in-c-additional-clocks-in-c-20-tvjsm1ztd) · Sandor Dargo · 4 upvotes · 1 comments --- Tags: [#distributed-systems](https://daily.dev/tags/distributed-systems) [View this post on daily.dev](https://daily.dev/posts/this-extra-second-keeps-crashing-the-internet-w4qmvu5p4) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"This Extra Second Keeps Crashing the Internet","url":"https://daily.dev/posts/this-extra-second-keeps-crashing-the-internet-w4qmvu5p4","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/this-extra-second-keeps-crashing-the-internet-w4qmvu5p4"},"datePublished":"2026-08-04T12:39:01.133Z","dateModified":"2026-08-04T12:39:23.649Z","description":"Devices keep time using quartz crystal oscillators that drift up to 20 seconds per month, requiring periodic sync with internet time servers via NTP. 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