The first day of the week in Things’ date pickers depends on the region settings of your device. If you want the week to start on a different day, here’s how to change the setting.

Mac
  1. On your Mac, quit Things.
  2. Go to Settings.
    • On macOS 13 (Ventura), go to System SettingsGeneralLanguage & Region.
    • On macOS 12 or older, go to System PreferencesLanguage & Region, and click Advanced…
  3. Set First day of week to your preferred weekday.
iPad & iPhone
  1. On your iPad or iPhone, open Things.
  2. Go to SettingsGeneralWeek.
  3. Tap the day on which you’d like the calendar week to start.
  4. Tap Done.