ustime.now guides & articles
10 in-depth guides on US Time and related topics.
US time explained
US time explained
Calling Across US Time Zones Without Waking Anyone
The coast-to-coast spread is three hours, and Alaska and Hawaii stretch it further. Here is the safe window for calling across US time zones, and the etiquette around it.
US time explained
ET vs EST vs EDT: Which One Should You Write?
ET is the year-round name for Eastern Time, EST is the winter half and EDT the summer half. Here is when each is correct and why the wrong one causes real confusion.
US time explained
US Time Zones Explained: All Six Zones, Offsets and Boundaries
A plain guide to the US time zones: the six standard zones covering the states, the offsets that define them, the territorial zones, and who sets the boundaries.
US time explained
When Does Daylight Saving Time Start and End?
Daylight saving time follows a fixed rule rather than a fixed date. Here is the rule, why the switch happens at 2:00 a.m. local, and why other countries change on other days.
States & territories
States & territories
Central Time Zone States: The Full List and the Split Edges
Ten states sit entirely in the Central Time zone and ten more sit partly in it. Here is the full list, the CST and CDT offsets, and where each boundary falls.
States & territories
Indiana Time Zone History: How One State Got So Complicated
For forty years Indiana ran on three different clock regimes at once. Here is how the Indiana time zone map got that way, and how it was finally sorted out in 2006.
States & territories
Pacific Time Explained: States, Offsets and the Three-Hour Gap
Pacific Time covers the West Coast and a little more besides. Here are the states it takes in, the PST and PDT offsets, and why the three-hour gap shapes the working day.
States & territories
States Split Between Time Zones: Where the Lines Fall
Roughly a dozen states are divided between two time zones. Here is where each boundary falls, which counties sit on the far side, and why the line follows commerce.
States & territories
States That Don't Observe Daylight Saving Time
Arizona and Hawaii are the two states that don't observe daylight saving, and the territories sit the change out as well. Here is who is exempt, and why they chose to be.
States & territories
US Territories Time: Atlantic, Chamorro and Samoa Zones
The US territories keep four zones of their own, from Atlantic time in Puerto Rico to Chamorro time in Guam. Here are the offsets, and why none of them changes clocks.