Calculating time difference with sky colors

Sometimes you just want to know what color the sky has in Tokyo.

It seems there are two main reasons to use a timezone calculator. The first one is to find out if you can call them without waking them up in the middle of the night. The other one is to find the least devastating time for a meeting between two or more timezones.

In the first case, you probably don’t need the exact time, but more something like the color of the sky.

In the second case, you need some exact times for the meeting invite.

So Kenneth and I made a website that does that – and only that. You can check it out on


We also made a Chrome extension. In both versions, you can either type in the hour you want to try out, or just use the arrow buttons to cycle through the day.


Ideas? Bugfixes? Github.

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