3MC was removed from the App Store in November 2022, but will be back.
I still use 3MC daily, along with several long-time users, and I have several planned improvements and great user feedback to implement. But it’s a side project to my main app, TimeStory, which has a very full plan for 2022/23, so those plans will take a little time. Meanwhile, I’ve also recently had one report of a pretty serious problem, which I’m not yet sure I have the right fix for.
So I’ve pulled the app from new sales. Existing installations should work just fine, and please reach out if you have any feedback or need any support. I’ll keep working on it on the side, and when it’s ready, I’ll be bringing it back.
Thanks for your support! I’ve left the rest of this page in place, as a reference. (And as a teaser!)
Contents: About | Help & Usage | Contact & Support | Acknowledgments | Release History
About 3MC
Three Month Calendar is a new and unique calendar-viewing app for your Mac’s menu bar. Fast and compact, it shows three months’ worth of weeks in a scrolling view, making it quick to answer questions about days, weeks, or upcoming events:

You can also integrate your personal calendars into the display. To keep the view compact and glanceable, 3MC lets you choose from a selection of marker types for any calendar you enable. These marker types use different positions and shapes, so they’re quick to spot, and combine well on busy days:

It has a variety of style and configuration options, and supports a systemwide keyboard shortcut as well as the Shortcuts app. Scroll down for a full walkthrough and help, or drop an email with any questions.
3MC is available on the Mac App Store. Up-front purchase; no ads, no
subscriptions.
Help & Usage
First-time setup
When you first launch 3MC, an intro window will appear. You probably want to check the “Start 3MC automatically” box. You can always change this later; see configuring startup, below.

General usage
Click on the menu bar icon to open or close 3MC. While open, it stays on top of all other windows and won’t take keyboard focus, so you can leave it up while working on other things.
With the calendar open, you can freely scroll up or down a few more months. If you scroll far enough in either direction, you’ll reach the end of the currently-loaded weeks; after you stop scrolling, 3MC will fill in more weeks in that direction.
(3MC currently loads 65 weeks at a time; 15 visible weeks plus 25 weeks in either direction. This ensures that three full months are always visible, and that roughly a year’s worth of time is easily scrollable.)
Right-click on the menu bar icon and choose Preferences to adjust the app’s configuration.
Configuring 3MC’s appearance
The Style tab lets you configure what parts of the calendar are shown and what theme is used. There are also two sizes available, depending on whether you want bigger text or a more compact presentation.

Configuring day markers and calendar access
The Markers tab of the preferences window lets you configure day markers. Today’s date is a built-in, or “standard”, marker, and you can adjust its appearance here.
You can also choose a marker to apply based on events from your macOS Calendar app. Click Enable next to “My Calendars” to load the list of available calendars; if this is the first time you’re doing so, macOS will prompt you for permission.

For any calendar marker, you can choose from a fixed set of marker types. This includes a few different background shapes, and underline, and a mark in any of the four corners of a date.
The calendar-event colors reflect the same colors used in the Calendar app; go to that app to adjust them. For today’s date, you can adjust the color directly within 3MC.
Viewing events
When a calendar day has one or more event markers on it, simply hover your mouse over it to see a brief summary. The squares reflect the calendar colors, and the events’ titles and time ranges are shown.

I made this up; I don't know anyone named J whose birthday is the 8th.
Configuring the 3-month view and pop-up event details
The “Options” tab in Preferences has two adjustments:
- Which three months should be shown when 3MC opens? The default is the three months starting with the current month. You can also ask it to start with last month (so that the current month is in the middle), or to start two months ago (so that the current month is at the bottom). Or set it to show the current calendar quarter.
- How to show event details, which only applies if you’ve enabled Calendar access. Whenever a marker appears on a day in the calendar, you can normally hover your mouse over that day to see a summary of the corresponding events. You can switch this to use a click, or to disable it entirely, if you’d like.

Configuring startup
To configure automatic startup at any time, use the Startup pane of the Preferences window.

If this is unchecked, the 3MC button will disappear from your menu bar whenever you log out and log back in (or restart your Mac). If this is checked, it will automatically show up.
(Technical note: 3MC installs itself by registering its own “3MC Launch at Login Helper” app with the system. This is separate from the Login Items list you’ll see in System Preferences, because Apple prevents sandboxed apps like 3MC from modifying that list.)
Configuring the keyboard shortcut
Click on the menu bar icon to pop open the calendar. Click on that icon again to dismiss it. You can also set up a global hot key:

Note on languages and regions
3MC was designed to adopt your Mac’s system-wide date format settings. I’ve personally tested it with a fair number of languages and settings, but it’s possible you’ll use a combination which doesn’t look quite right; let me know and I’ll try to fix it. (3MC’s menus and dialogs are all in US English, however.)
Contact & Support
Questions? Problems? Feature requests? Complaints? Praise? Drop me a line at 3mc@casualprogrammer.com.
3MC is a side project; my energy is mostly on TimeStory. But I’d love to make it as useful and fun as possible, while keeping it small, fast, and focused.
If you’d like to review 3MC, feel free to use the screenshots on this page, and drop me a line with any questions.
Acknowledgments
3MC 2 uses Sindre Sorhus’s very nice KeyboardShortcuts package for Swift. This provides the code to choose and handle global Mac keyboard shortcuts. It’s easy to use, well-documented, and available under the MIT license.
Release History
- 3MC was removed from the Mac App Store on November 8, 2022. See the note at the top of this page.
- Version 2.1.1 was released on October 27. 2022. It was updated for macOS Ventura; 3MC needed to adapt to an OS-level change to how Preferences is shown, and Ventura introduced a strange lag which needed to be worked around. 2.1.1 also included other internal updates to take advantage of some of Apple’s newer APIs.
- Version 2.1 was released on March 3, 2022. It improved the event details popup, replaced the buttons which extended the scroll view up or down with automatic extension, and added the option for the three months ending with this one.
- Version 2 was released on February 14, 2022. It added Calendar integration, keyboard shortcut support, the configurable Today marker, the Options tab (and thus the ability to select which three months to show), Shortcuts actions, and a new app icon.
- Version 1 was released on November 3, 2021. I built 3MC because I wanted precisely this app, and for fun, to play with SwiftUI in between major releases of TimeStory. (It was inspired by an app I’d written many years earlier.)
Orange Beach, Alabama
…is where I took the photo in the desktop background.