You can share the McClure calendar so that it shows up in your default calendar app. To do this:
First, go to McClure's Calendar page and click the share button. In the menu that opens, click the iCal/RSS Feed button.
From the page that opens, you can get the links to add a feed to other calendars. To add it to Google Calendar, follow these steps from Google:
https://support.google.com/calendar/answer/37100?co=GENIE.Platform%3DDesktop&hl=en
To add it to Microsoft Outlook.com, you will want to "Subscribe to a calendar" as described here:
https://support.microsoft.com/en-us/office/import-or-subscribe-to-a-calendar-in-outlook-com-cff1429c-5af6-41ec-a5b4-74f2c278e98c