Vernal equinox | Definition, Dates, & Facts

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d-flex align-items-center"> <div class="tlr-title px-20 py-15 text-left"> <em class="material-icons text-gray-400 d-lg-none" data-icon="toc"></em> <a class="font-serif font-weight-bold text-black link-blue" href="https://www.britannica.com/science/vernal-equinox">vernal equinox</a> </div> <button aria-label="Close" class="js-sections-close-button btn-link btn-sm btn d-lg-none position-absolute top-0 p-10 right-0" > <em class="material-icons font-26" data-icon="close"></em> </button> </div> <div class="section-content pl-10 pr-20 pl-sm-50 pr-sm-60 pl-lg-5 pr-lg-10 pt-10 pt-lg-0 bg-gray-50 clear-catfish-ad"> <div class="toc mb-20"> <div class="font-serif font-14 font-weight-bold mx-15 mb-15 mt-20"> Table of Contents </div> <span class="toc-extra-link selected link-gray-900 mt-15"> Introduction </span> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/science/vernal-equinox/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" 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Let us know if you have suggestions to improve this article (requires login). </div> <div class="type-menu"> <label for="feedback-type" class="label mb-10">Feedback Type</label> <select id="feedback-type" class="form-select mb-30" name="feedbackTypeId" required> <option value="" selected="selected">Select a type (Required)</option> <option value="1">Factual Correction</option> <option value="2">Spelling/Grammar Correction</option> <option value="3">Link Correction</option> <option value="4">Additional Information</option> <option value="5">Other</option> </select> </div> <label for="feedback" class="label mb-10">Your Feedback</label> <textarea id="feedback" class="form-control mb-30" name="feedback" maxlength="3000" rows="7" required></textarea> <button class="btn btn-blue" type="submit">Submit Feedback</button> </form> <div class="success-messaging d-none mt-30"> <div class="title">Thank you for your feedback</div> <p>Our editors will review what you’ve submitted and determine whether to revise the article.</p> </div> </div> </div> <div class="md-websites-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom font-weight-bold"> External Websites </div> <div class="pb-20"> <ul class="list-unstyled mt-20 lh-lg"> <li><a class="external" href="https://www.space.com/vernal-equinox-2024-spring-northern-hemisphere" target="_blank" rel="noopener ">Space.com - Vernal equinox 2024 brings spring to the Northern Hemisphere today</a></li> <li><a class="external" href="https://www.nesdis.noaa.gov/news/earth-orbit-vernal-equinox" target="_blank" rel="noopener ">NOAA National Environmental Satellite, Data, and Information Service - Earth from Orbit: Vernal Equinox</a></li> <li><a class="external" href="https://www.academia.edu/98791155/Spring_Equinox_as_Depicted_in_the_Indus_Seal" target="_blank" rel="noopener ">Academia - Spring Equinox, as Depicted in the Indus Seal (PDF)</a></li> </ul> </div> </div> </div> </div> </div> <div class="toc-header-marker"></div> <button class="ai-ask-button btn btn-sm border-2 btn-outline-red-400 border-red-400 d-none mr-0 mr-lg-10 ml-5 ml-sm-10 ml-lg-0 p-10 px-sm-5 px-md-10 js-header-ai-ask-button"> Ask the Chatbot a Question </button> <div class="caption alternate-titles">Also known as: first point of Aries, spring equinox</div> <div class="md-byline module-spacing "> <div class="font-serif font-12"> <span class="written-by text-gray-700"> Written and fact-checked by </span> <div class="editor-popover popover p-0"> <a class="d-block p-20 qa-editor-popup gtm-byline font-12 byline-contributor" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> The Editors of Encyclopaedia Britannica</span></div> <div class="last-updated font-12 font-serif"> <span class="text-gray-700"> Last Updated: <time datetime="2025-02-07T00:00:00CST" >Feb 7, 2025</time> •</span> <a class="byline-edit-history" href="https://www.britannica.com/science/vernal-equinox/additional-info#history" rel="nofollow">Article History</a> </div></div> </div> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button d-none d-sm-block js-sections-inline-button module-spacing btn d-lg-none"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <div class="d-flex d-sm-none flex-row"> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button js-sections-inline-button module-spacing"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <button class="ai-ask-button btn btn-sm border-2 btn-outline-red-400 border-red-400 module-spacing js-inline-ai-ask-button p-10 ml-5"> Ask the Chatbot </button> </div> <div class="js-qf-module qf-module px-40 px-sm-20 py-15 mx-auto module-spacing font-14 bg-gray-50 rounded"> <div class="facts-list mt-10"> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Related Topics: </dt> <dd><a href="/topic/Wicca" topicid="703384">Wicca</a></dd> <dd><a href="/topic/Vishu" topicid="2146333">Vishu</a></dd> <dd><a href="/science/spring-season" topicid="561288">spring</a></dd> <dd><a href="/topic/March-month" topicid="364137">March</a></dd> <dd><a href="/topic/September" topicid="535087">September</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> <div class="text-center"> <a class="btn btn-sm btn-link p-0" href="/facts/vernal-equinox"> See all related content </a> </div> </div> </div> </div><span class="marker before-article"></span><section data-level="1" id="ref1"><span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph"><strong><span id="ref1204781"></span>vernal equinox</strong>, two moments in the year when the <a href="https://www.britannica.com/place/Sun" class="md-crosslink " data-show-preview="true">Sun</a> is exactly above the <a href="https://www.britannica.com/place/Equator" class="md-crosslink " data-show-preview="true">Equator</a> and day and night are of equal length; also, either of the two points in the sky where the <a href="https://www.britannica.com/science/ecliptic" class="md-crosslink " data-show-preview="true">ecliptic</a> (the Sun’s annual pathway) and the <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="celestial" href="https://www.britannica.com/dictionary/celestial" data-type="EB">celestial</a> equator intersect. In the Northern Hemisphere the vernal equinox falls about March 20 or 21, as the Sun crosses the celestial equator going north.</p><div class="one-good-fact-module"> </div><span class="marker MOD1 mod-inline"></span><span class="marker PREMOD2 mod-inline"></span><div class="assemblies"><div class="w-100 assembly-container"><figure class="md-assembly m-0 mb-md-0 card card-borderless print-false" data-assembly-id="285875" data-asm-type="video"><div class="md-assembly-wrapper card-media" data-type="video" video-id="247262"><a data-id="247262" class="gtm-assembly-link d-flex justify-content-center" style="--aspect-ratio: 16/9" href="/video/what-causes-seasons/-285875"><img src="https://cdn.britannica.com/62/247262-138-1891B9BE/what-causes-seasons.jpg?w=800&h=450&c=crop" alt="What causes the seasons?" loading="lazy"><script type="application/json"> { "sources": [ { "file" : "//content.jwplatform.com/manifests/swgj17qE.m3u8" } ], "image": "https://cdn.britannica.com/62/247262-138-1891B9BE/what-causes-seasons.jpg" ,"tracks": [ { "file" : "//assets-jpcust.jwpsrv.com/tracks/vuHJ17zC.vtt", "label": "English" } ] ,"adfile": "//content.jwplatform.com/manifests/CUMwogta.m3u8" } </script><div class="btn btn-xl btn-white btn-circle position-absolute shadow" style="top: 50%; transform: translateY(-50%)"><em class="material-icons" data-icon="play_arrow"></em></div></a></div><figcaption class="card-body"><div class="md-assembly-caption text-muted font-14 font-serif line-clamp"><span><span class="md-assembly-title font-weight-bold mr-5 d-inline font-sans-serif md-video-caption" video-control="247262">What causes the seasons?</span><span>In many parts of the world, weather cycles through the four seasons like clockwork: spring, summer, autumn, and winter.</span><button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"><span class="link-blue">(more)</span></button></span></div><a class="font-14 mt-10 d-inline-block" href="/science/vernal-equinox/images-videos">See all videos for this article</a></figcaption></figure></div></div><p class="topic-paragraph">In the Southern Hemisphere the <a href="https://www.britannica.com/science/equinox-astronomy" class="md-crosslink autoxref " data-show-preview="true">equinox</a> occurs on September 22 or 23, when the Sun moves south across the celestial equator. According to the astronomical definition of the <a href="https://www.britannica.com/science/season" class="md-crosslink " data-show-preview="true">seasons</a>, the vernal equinox also marks the beginning of <a href="https://www.britannica.com/science/spring-season" class="md-crosslink " data-show-preview="true">spring</a>, which lasts until the <a href="https://www.britannica.com/science/summer-solstice-astronomy" class="md-crosslink " data-show-preview="true">summer solstice</a> (June 20 or 21 in the Northern Hemisphere, December 21 or 22 in the Southern Hemisphere).</p><span class="marker MOD2 mod-inline"></span></section> <span class="md-signature font-12"><a href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419">The Editors of Encyclopaedia Britannica</a></span> <span class="md-signature font-12">This article was most recently revised and updated by <a href="/editor/Meg-Matthias/12593612">Meg Matthias</a>.</span><span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-simplify-root"></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article> </div> </div> </div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":1,"pagesTotal":1,"pageId":626277,"pageLength":126,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-134/js/libs/jquery-3.5.0.min.js?v=3.134.26"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-134/dist/topic-page.js?v=3.134.26' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"C","adLeg":"C","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"SMALL","gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":true,"hasAiTopQuestions":false,"hasSimplifyButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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Vernal equinox | Definition, Dates, & Facts | Britannica