Is it possible to display the clock on the taskbar on each screen in Windows 8, preferably without 3rd-party tools?
Windows 10 Anniversary Update (version 1607, build 14393.10) was pushed to standard update channels on August 2 2016, and now there is no longer any need to install third party software to use dual monitor taskbar clocks.
This screenshot of a dual-monitor setup shows the clock on both the left and the right monitor taskbars outlined in red. No additional configuration is required (other than allowing the install of the update).
- Ultramon - ($$ but 30-day free trial period) mentioned by @Robert Kelly
- DisplayFusion - Only the Pro versions ($$ but 30-day free trial period) show the clock on all taskbars. Free version does not.
- Actual Multiple Monitors - 30-day free trial period
- MultiMon - Lighter weight version of zbar and ultramon, and easier to set up. Free version designed for XP. Paid versions have not been updated recently (no info on Win8+ support).
- T-Clock Redux - Free and open source (GitHub - pre-compiled binaries are available).
Finally, not a taskbar clock per se, but DexClock is an interesting (free) wallpaper-based clock solution that might address your needs.
Possible with a program called Ultramon. Link
Of course, this is WITH 3rd party tools, but it looks completely native once you get it setup. Just if you're still looking for a solution! Good luck.
For win7 there is an open-source tool: https://sourceforge.net/projects/dualmonitortb
It's a little bit unstable, but it does the job perfectly