<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 06-June-2022 [10:18:42] {PM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<roleRef xlink:type="simple" xlink:href="swx-20220324.xsd#Cover" roleURI="http://Southwest.com/role/Cover" />
<calculationLink xlink:type="extended" xlink:role="http://Southwest.com/role/Cover">
</calculationLink>
</linkbase>
