Thunderbird Lightning Calendar
Free
Thunderbird Lightning is an extension for the Thunderbird email client, offering powerful calendar functionality. It supports multiple calendars, to-dos, and event reminders.

Our take
Great for Thunderbird users looking to add calendar functionality.
Alright, so I gave the Thunderbird Lightning Calendar a spin, and let me tell you, it’s got its ups and downs. On the bright side, it’s like having a trusty old calendar but right on your screen. It integrates seamlessly with Thunderbird email, so if you’re already using Thunderbird, this could be a no-brainer. You can manage your emails and schedule all in one place, which is pretty convenient if you ask me. But, if you're not a Thunderbird user, the calendar might feel like an unnecessary addition to your digital clutter.
I found the user interface a bit clunky at times, though. It's not exactly modern-looking, and it's kind of like stepping back in time. If you’re a fan of slick, cutting-edge design, this might not be your cup of tea. The layout is functional, sure, but it doesn’t have that polished feel that some other calendar apps boast. But hey, if you prefer function over form, this might be right up your alley.
Setting up events and tasks is straightforward, which is a relief because some apps make it way too complicated. It’s got all the basic features you'd expect, like reminders, recurring events, and task lists. You won’t get lost in a sea of unnecessary options, which is nice. But don’t expect any fancy AI magic or smart suggestions. It’s pretty bare-bones, and some might find that refreshing, while others might see it as a missed opportunity.
One thing to note is that syncing across devices can be a bit of a hassle. You’ll need to jump through a few hoops to get it working smoothly, especially if you’re trying to sync with non-Thunderbird apps. It doesn’t have that out-of-the-box ease of use for cross-platform syncing that some other calendars offer. So if you’re someone who relies on seamless integration across multiple gadgets, this could be a sticking point.
In a nutshell, the Thunderbird Lightning Calendar is like your reliable, no-frills buddy who gets the job done without any fuss. It’s not going to blow your mind with cutting-edge features, but if you’re looking for a straightforward calendar that plays nice with Thunderbird email, it could be just what you need. Just be ready to deal with some quirks and a bit of a retro vibe. If you’re cool with that, it might just work out for you.