When the time zone of the Windows operating system is set to the America/Asuncion time zone, the time zone offset error is one hour.

[xingyixiang]

Describe the bug
When the time zone of the Windows operating system is set to the America/Asuncion time zone, the time zone offset error is one hour.
Daylight Saving Time: UTC-3
Standard Time: UTC-4

Windows操作系统时区设置为(UTC-04:00) 亚松森 时区，时区偏移量误差1小时。
夏令时是：UTC-3
标准时间是：UTC-4

it('test America/Asuncion', () => {
  const testDate = dayjs.utc('2025-03-23T03:20:57.000+00:00').tz('America/Asuncion').format('YYYY-MM-DD HH:mm:ssZ')
  expect(testDate).toBe('2025-03-22 23:20:57-04:00')
})

Result
2025-03-22 23:20:57-05:00

Expected behavior
2025-03-22 23:20:57-04:00

Information

• Day.js Version - 1.11.13
• windows 10
• Browser [chrome 132.0.6834.84]
• Time zone: [GMT-04:00 DST (America/Asuncion)]

[xingyixiang]

[fformigli]

FYI
On october 2024 the Congress of Paraguay passed a bill to observe UTC-3 permanently, equivalent to permanent DST

https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/LXAN4PAEWYEWQJVYGSJ5NPIWWYQ2NHFZ/

[xingyixiang]

FYI On october 2024 the Congress of Paraguay passed a bill to observe UTC-3 permanently, equivalent to permanent DST

https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/LXAN4PAEWYEWQJVYGSJ5NPIWWYQ2NHFZ/

Therefore, the calculation should be UTC-3 or UTC-4 instead of UTC-5.

[Qiming-Liu]

I got -4
https://codesandbox.io/p/sandbox/htxgsy

[xingyixiang]

I got -4 https://codesandbox.io/p/sandbox/htxgsy

Set the time zone of the Windows operating system to be the same as the time zone to be tested.

[xingyixiang]

Can the problem be reproduced? @Qiming-Liu

[Qiming-Liu]

Yeah, I think it is the same as #2303

[xingyixiang]

Yeah, I think it is the same as #2303

It's the same problem