Asia/Colombo

Time zone identifier: Asia/Colombo

Current civil offset: +05:30 (+0530)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1879-12-31

Local Mean Time (LMT): +05:19:24 based on geographic meridian

Total recorded transitions: 8 transitions across 5 distinct offsets

Associated countries: LK

Advertisement Space

Historical Offset Step Chart (1880 to Present)

+4:00 +5:00 +6:00 +7:00 +8:00 1880 1900 1920 1940 1960 1980 2000 2020

Text summary: Asia/Colombo shifted between 5 distinct offsets from 1879-12-31 through the modern era.

Complete Transition History (8 Transitions)

UTC Instant Local Wall Time Shift Abbreviation DST Effect
1879-12-31T18:40:36Z 1880-01-01 00:00:08 +05:19:24 → +05:19:32 MMT No gap
1905-12-31T18:40:28Z 1906-01-01 00:10:28 +05:19:32 → +05:30 +0530 No gap
1942-01-04T18:30:00Z 1942-01-05 00:30:00 +05:30 → +06:00 +06 Yes gap
1942-08-31T18:00:00Z 1942-09-01 00:30:00 +06:00 → +06:30 +0630 Yes gap
1945-10-15T19:30:00Z 1945-10-16 01:00:00 +06:30 → +05:30 +0530 No overlap
1996-05-24T18:30:00Z 1996-05-25 01:00:00 +05:30 → +06:30 +0630 No gap
1996-10-25T18:00:00Z 1996-10-26 00:00:00 +06:30 → +06:00 +06 No overlap
2006-04-14T18:30:00Z 2006-04-15 00:00:00 +06:00 → +05:30 +0530 No overlap

Notes from the Maintainers

Source: asia (Lines 3863 to 3917)
Spratly Is
no information

Sri Lanka

From Paul Eggert (2013-02-21):
Milne says "Madras mean time use from May 1, 1898.  Prior to this Colombo
mean time, 5h. 4m. 21.9s. F., was used."  But 5:04:21.9 differs considerably
from Colombo's meridian 5:19:24, so for now ignore Milne and stick with
Shanks and Pottenger.

From Paul Eggert (1996-09-03):
"Sri Lanka advances clock by an hour to avoid blackout"
(<http://www.virtual-pc.com/lankaweb/news/items/240596-2.html>, 1996-05-24,
no longer available as of 1999-08-17)
reported "the country's standard time will be put forward by one hour at
midnight Friday (1830 GMT) 'in the light of the present power crisis'."

From Dharmasiri Senanayake, Sri Lanka Media Minister (1996-10-24), as quoted
by Shamindra in Daily News - Hot News Section
<news:54rka5$m5h@mtinsc01-mgt.ops.worldnet.att.net> (1996-10-26):
With effect from 12.30 a.m. on 26th October 1996
Sri Lanka will be six (06) hours ahead of GMT.

From Jesper Nørgaard Welen (2006-04-14), quoting Sri Lanka News Online
<http://news.sinhalaya.com/wmview.php?ArtID=11002> (2006-04-13):
0030 hrs on April 15, 2006 (midnight of April 14, 2006 +30 minutes)
at present, become 2400 hours of April 14, 2006 (midnight of April 14, 2006).

From Peter Apps and Ranga Sirila of Reuters (2006-04-12) in:
http://today.reuters.co.uk/news/newsArticle.aspx?type=scienceNews&storyID=2006-04-12T172228Z_01_COL295762_RTRIDST_0_SCIENCE-SRILANKA-TIME-DC.XML
[The Tamil Tigers] never accepted the original 1996 time change and simply
kept their clocks set five and a half hours ahead of Greenwich Mean
Time (GMT), in line with neighbor India.
From Paul Eggert (2006-04-18):
People who live in regions under Tamil control can use [TZ='Asia/Kolkata'],
as that zone has agreed with the Tamil areas since our cutoff date of 1970.

From Sadika Sumanapala (2016-10-19):
According to http://www.sltime.org (maintained by Measurement Units,
Standards & Services Department, Sri Lanka) abbreviation for Sri Lanka
standard time is SLST.

From Paul Eggert (2016-10-18):
"SLST" seems to be reasonably recent and rarely used outside time
zone nerd sources.  I searched Google News and found three uses of
it in the International Business Times of India in February and
March of this year when discussing cricket match times, but nothing
since then (though there has been a lot of cricket) and nothing in
other English-language news sources.  Our old abbreviation "LKT" is
even worse.  For now, let's use a numeric abbreviation; we can
switch to "SLST" if it catches on.

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

Attributed Statements:

Paul Eggert (2013-02-21):

Milne says "Madras mean time use from May 1, 1898. Prior to this Colombo mean time, 5h. 4m. 21.9s. F., was used." But 5:04:21.9 differs considerably from Colombo's meridian 5:19:24, so for now ignore Milne and stick with Shanks and Pottenger.

Paul Eggert (1996-09-03):

"Sri Lanka advances clock by an hour to avoid blackout" (<http://www.virtual-pc.com/lankaweb/news/items/240596-2.html>, 1996-05-24, no longer available as of 1999-08-17) reported "the country's standard time will be put forward by one hour at midnight Friday (1830 GMT) 'in the light of the present power crisis'." From Dharmasiri Senanayake, Sri Lanka Media Minister (1996-10-24), as quoted by Shamindra in Daily News - Hot News Section <news:54rka5$m5h@mtinsc01-mgt.ops.worldnet.att.net> (1996-10-26): With effect from 12.30 a.m. on 26th October 1996 Sri Lanka will be six (06) hours ahead of GMT. From Jesper Nørgaard Welen (2006-04-14), quoting Sri Lanka News Online <http://news.sinhalaya.com/wmview.php?ArtID=11002> (2006-04-13): 0030 hrs on April 15, 2006 (midnight of April 14, 2006 +30 minutes) at present, become 2400 hours of April 14, 2006 (midnight of April 14, 2006). From Peter Apps and Ranga Sirila of Reuters (2006-04-12) in: http://today.reuters.co.uk/news/newsArticle.aspx?type=scienceNews&storyID=2006-04-12T172228Z_01_COL295762_RTRIDST_0_SCIENCE-SRILANKA-TIME-DC.XML [The Tamil Tigers] never accepted the original 1996 time change and simply kept their clocks set five and a half hours ahead of Greenwich Mean Time (GMT), in line with neighbor India.

Paul Eggert (2006-04-18):

People who live in regions under Tamil control can use [TZ='Asia/Kolkata'], as that zone has agreed with the Tamil areas since our cutoff date of 1970.

Sadika Sumanapala (2016-10-19):

According to http://www.sltime.org (maintained by Measurement Units, Standards & Services Department, Sri Lanka) abbreviation for Sri Lanka standard time is SLST.

Paul Eggert (2016-10-18):

"SLST" seems to be reasonably recent and rarely used outside time zone nerd sources. I searched Google News and found three uses of it in the International Business Times of India in February and March of this year when discussing cricket match times, but nothing since then (though there has been a lot of cricket) and nothing in other English-language news sources. Our old abbreviation "LKT" is even worse. For now, let's use a numeric abbreviation; we can switch to "SLST" if it catches on. Zone NAME STDOFF RULES FORMAT [UNTIL]

Years on Record

Methodology Note: The 1970 Rule

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.