JavaScript Temporal vs Date
Difference Between Date and Temporal
- Date mixes date and time zone
- Date parsing is inconsistent
- Date is 0-based / Temporal is 1-based
- Date millisecond / Temporal nanosecond
Date and Time Zone
new Date(2026, 4, 1) creates a timestamp of your local time zone at midnight.
This means it can "shift" when you format it in UTC or in another zone.
Example
// Months are 0-based (4 = May)
const d = new Date(2026, 4, 1);
// Might be 2026-04-30T22:00:00.000Z in some time zones:
d.toISOString();
Temporal.PlainDate is not a timestamp.
It is just "2026-05-01" with no time and no time zone, so there can not be any shifting.
Date Parsing is Inconsistent
new Date("2026-05-01") parses as an instant (often treated as UTC by spec in modern JS),
but historically it has been a minefield of different formats, browser quirks and locale surprises.
Temporal avoids this by:
- defining strict parsing rules for ISO strings
- using Temporal.Instant.from() for clearly-typed conversions
Temporal is 1-Based
- Date: January = 0
- Temporal: January = 1 (much more human-friendly)
Example
// May 1:
new Date(2026, 4, 1)
// May 1:
new Temporal.PlainDate(2026, 5, 1)
Nanosecond Precision
Unlike the Date object which uses milliseconds, Temporal.Instant offers 1000 times higher nanosecond precision.
Browser Support
Temporal is an ES2026 feature. It is not fully supported in all browsers:
| Chrome 144 |
Edge 144 |
Firefox 139 |
Safari |
Opera |
| Jan 2026 | Jan 2026 | May 2025 | 🚫 | 🚫 |
