Dr J R Stockton
1/11/2016 8:57:00 PM
In comp.lang.javascript message <473a3ab3-1f5c-4bae-9e0b-63ebc92f9826@go
oglegroups.com>, Sun, 10 Jan 2016 02:53:08, Simon Blackwell
<syblackwell@anywhichway.com> posted:
>3) time zone conversions
Please be careful to honour the proper definition of Time Zone. A Time
Zone is the set of places for which Standard Local Time (and Date) is
the same; and Standard Local Time is Winter Time (whether centred about
January or July). Summer Time, where it is used, is advanced from
Winter/Standard Time by a half or one hour, and does not affect Time
Zone at all. Remember too that in the 'forties the British Isles, or at
least the UK, sometimes used Double Summer Time.
New York, USA, use EST as a Winter offset indicator and EDT as a summer
one, and (more rarely) uses ET to indicate New York Local Civil Time
(LCT).
Actually, in some places LCT is officially governed by GMT and in others
it is governed by UTC - that difference is ignored in considering the
Time Zone.
Note that there is a region where the date of the end of Summer Time is
sometimes affected by the Date of Easter Sunday.
I have code to transfer date/time between any two locations for which an
M-type TZ string can be given. Use The Wayback Machine for site
merlyn.demon.co.uk.
Do not check your Week Number code, if any, against Microsoft DatePart,
except for purposes of amusement.
See Wikipedia, BIPM?, NPL, NIST, etc.
--
(c) John Stockton, Surrey, UK. ¬@merlyn.demon.co.uk Turnpike v6.05 MIME.
Merlyn Web Site < > - FAQish topics, acronyms, & links.