On 3/5/20 4:12 PM, Arthur David Olson wrote:
> 1. What's the best available statement on desirable lead times?

<https://data.iana.org/time-zones/tz-link.html#changes> says this:

"If your government plans to change its time zone boundaries or daylight
saving rules, inform tz@iana.org well in advance, as this will
coordinate updates to many cell phones, computers, and other devices
around the world. With less than a year's notice there is a good chance
that some computer-based clocks will operate incorrectly after the
change, due to delays in propagating updates to software and data. The
shorter the notice, the more likely clock problems will arise; see 'On
the Timing of Time Zone Changes' for examples."

> 2. In the case at hand, is changing to "on the second Sunday of March in
> the year after the change" sufficient?

Most likely. It depends on whether the federal change gives us enough
notice. Last time it did, and I'd expect the same this time.