Surprised it hasn't been nominated yet - jiff by BurntSushi himself
In case you haven't heard of it before, Jiff is a relatively new datetime
library for Rust. Jiff takes enormous inspiration from Temporal. Jiff
supports automatic and seamless integration with the Time Zone Database, DST
aware arithmetic and rounding, formatting and parsing zone aware datetimes
losslessly, opt-in Serde support and a whole lot more. Jiff's overall goal
is to guide you into the pit of success and make it harder to write buggy
code for handling datetimes.
( from Release 0.2.0 · BurntSushi/jiff · GitHub )
It's basically a more modern (with a different philosophy) and arguably better take on chrono