The French actually tried it, here's the Wikipedia article.

A more reasonable thing to do is something like Swatch Internet Time, you get 1000 ".beats" in a day with no time zones. Beyond a day it might not be too helpful to keep decimal, there will be 365+fraction days a year no matter how you measure it.

Seconds are already an SI unit. We'd have to redo every textbook, and overcome centuries of work.

One day is a Dec, 10 Decs in a Wec, 10 Wecs in a Mec and 100 Mecs in a Yec. Your days are split into Ceti-decs and Micro-decs!

Lemmy is serious business!

Starting from 1 year being 365 days

1 month would be the equivalent of 3.65 days
1 day would be 52.5 minutes
1 hour would be 31.5 seconds
1 minute would be 0.3 seconds
1 second would be 3 milliseconds
1 millisecond would be 3 nanoseconds

[French revolution intensifies]

Unfortunately with dates you also want to incorporate the natural cycles of the earth and sun, which not only aren't decimal but usually incommensurable, so it's a hard thing to do. The French just had a block of their calendar that didn't count as "real" days IIRC.

If we start seriously going to space, doing everything by Unix epoch (count of seconds since the 60's ended) would make sense, and planning your day might well go by kiloseconds. Someone on here suggested giving up on standardised time zones and just doing everything long-distance that way even on Earth, which grew on me as an idea.

Didn't downvote but TPO my dude