# Is Dates.UTInstant UT1, UT2, or UTC?

**URL:** <https://discourse.julialang.org/t/is-dates-utinstant-ut1-ut2-or-utc/12051>\
**Category:** General Usage\
**Tags:** question\
**Created:** [June 29, 2018, 1:15am UTC](https://discourse.julialang.org/t/is-dates-utinstant-ut1-ut2-or-utc/12051 "2018-06-29T01:15:03Z")\
**Posts on this page:** 1\
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**Author:** ![ssfrr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ssfrr/32/3736_2.png) [@ssfrr](https://discourse.julialang.org/u/ssfrr)\
**Post date:** [June 29, 2018, 1:42am UTC](https://discourse.julialang.org/t/is-dates-utinstant-ut1-ut2-or-utc/12051/2 "2018-06-29T01:42:39Z")

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There’s a footnote in the [Dates docs](https://docs.julialang.org/en/latest/stdlib/Dates/#Dates-1) that says they’re UT1.

There have been a few long threads comparing various time representations. Here’s one:

> [@Higher resolution DateTime/TimeStamp](https://discourse.julialang.org/t/higher-resolution-datetime-timestamp/3069/19):
>
> Nothing ambiguous about it: Base’s time is in [UT1](https://en.wikipedia.org/wiki/Universal_Time#Versions), modulo time zones (which are a whole other can of worms). This is in contrast to many other language’s time systems which claim to be in UTC and then ignore leap seconds – which is contradictory, not just ambiguous.

I think there have been more…

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_[View the full topic](https://discourse.julialang.org/t/is-dates-utinstant-ut1-ut2-or-utc/12051)._