Why does a subscribed calendar take forever to update?

When you subscribe to an iCal feed using a URL, you are telling your calendar application (Google Calendar, Apple Calendar, Outlook, etc.) to periodically check that URL for updates.

However, this process is not instantaneous. Every calendar provider has its own refresh schedule, and most do not allow you to manually force a refresh.

Important: This delay only applies to subscribed calendars (those added via a URL). It does not apply to downloaded iCal files that you import manually. When you import a file, the events are added immediately to your calendar. Events from downloaded calendars do not automatically update.

Google Calendar

Google Calendar is known for having a slow refresh rate for external iCal feeds. It typically updates once every 24 hours. Unfortunately, Google does not provide a button or setting to increase this frequency. If you’ve just updated your source file or made changes to the source calendar, it may take a full day before those changes appear in your Google Calendar.

Apple Calendar (macOS & iOS)

Apple Calendar is more flexible. By default, it might refresh every hour or every day, but you can usually change this in Settings:

1. Right-click on the subscribed calendar in the sidebar.
2. Select Get Info.
3. Change the Auto-refresh interval (e.g., to “Every 15 minutes”).

Microsoft Outlook

Outlook (Web and Desktop) generally refreshes external feeds every few hours, though this can vary based on your specific account type and settings.

Workaround

If you need to see your changes immediately, for testing purposes, you can often force a refresh by slightly altering the URL:

• Add a dummy parameter to the end of your iCal URL, like ?refresh=1.
• Your calendar app will treat this as a brand new URL and fetch the latest data immediately.
• Note that this creates a new subscription; you’ll likely want to delete the old one to avoid duplicates.