# Strainge Time Behaviour **URL:** \ **Category:** ruby-talk\ **Created:** [11 December 2002 17:19 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535 "2002-12-11T17:19:55Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Travis](https://avatars.discourse-cdn.com/v4/letter/t/bbce88/32.png) [@Travis](https://rubytalk.org/u/Travis)\ **Post date:** [11 December 2002 17:19 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/1 "2002-12-11T17:19:55Z")
I’m manipulating some dates, and I just found something weird. ruby -v ruby 1.6.7 (2002-03-01) [i586-mswin32] # works as expected irb(main):001:0\> Time.local(2002, 4, 29) Mon Apr 29 00:00:00 EDT 2002 irb(main):002:0\> Time.local(2002, 4, 29) + 86400 Tue Apr 30 00:00:00 EDT 2002 # weird behaviour irb(main):004:0\> Time.local(2002, 10, 27) Sun Oct 27 00:00:00 EDT 2002 irb(main):005:0\> Time.local(2002, 10, 27) + 86400 Sun Oct 27 23:00:00 EST 2002 So, adding the amount of seconds to equal one day to 10/27/2002 only brings it up to 23:00. If this is something completely obvious, please enlighten me. It’s causing quite a stir in my program… Sincerely, Travis Whitton [whitton@atlantic.net](mailto:whitton@atlantic.net) ---
**Author:** ![Paul\_E.C\_Melis](https://avatars.discourse-cdn.com/v4/letter/p/c4cdca/32.png) [@Paul\_E.C\_Melis](https://rubytalk.org/u/Paul_E.C_Melis)\ **Post date:** [11 December 2002 17:20 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/2 "2002-12-11T17:20:00Z")
> # weird behaviour > > irb(main):004:0\> Time.local(2002, 10, 27) > Sun Oct 27 00:00:00 EDT 2002 > irb(main):005:0\> Time.local(2002, 10, 27) + 86400 > Sun Oct 27 23:00:00 EST 2002 Note the difference in type of time returned: EDT vs. EST The first is Eastern Daylight (savings) Time, the second is Eastern Standard Time, that should explain the difference of 1 hour. But it’s strange of course, it should return the same types regardless. Paul ---
**Author:** ![Ara.T.Howard1](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ara.T.Howard1](https://rubytalk.org/u/Ara.T.Howard1)\ **Post date:** [11 December 2002 17:40 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/3 "2002-12-11T17:40:05Z")
[snip] > I’m manipulating some dates, and I just found something weird. > [snip] and even weirder : ~ \> irb irb(main):001:0\> t = Time.local(2002, 10, 27) Sun Oct 27 00:00:00 MDT 2002 irb(main):002:0\> 24.times do |h| irb(main):003:1\* p t + 3600 \* h irb(main):004:1\> end Sun Oct 27 00:00:00 MDT 2002 Sun Oct 27 01:00:00 MDT 2002 Sun Oct 27 01:00:00 MST 2002 Sun Oct 27 02:00:00 MST 2002 Sun Oct 27 03:00:00 MST 2002 Sun Oct 27 04:00:00 MST 2002 Sun Oct 27 05:00:00 MST 2002 Sun Oct 27 06:00:00 MST 2002 Sun Oct 27 07:00:00 MST 2002 Sun Oct 27 08:00:00 MST 2002 Sun Oct 27 09:00:00 MST 2002 Sun Oct 27 10:00:00 MST 2002 Sun Oct 27 11:00:00 MST 2002 Sun Oct 27 12:00:00 MST 2002 Sun Oct 27 13:00:00 MST 2002 Sun Oct 27 14:00:00 MST 2002 Sun Oct 27 15:00:00 MST 2002 Sun Oct 27 16:00:00 MST 2002 Sun Oct 27 17:00:00 MST 2002 Sun Oct 27 18:00:00 MST 2002 Sun Oct 27 19:00:00 MST 2002 Sun Oct 27 20:00:00 MST 2002 Sun Oct 27 21:00:00 MST 2002 Sun Oct 27 22:00:00 MST 2002 24 irb(main):005:0\> p t + 3600 \* 1 Sun Oct 27 01:00:00 MDT 2002 nil irb(main):006:0\> p t + 3600 \* 2 Sun Oct 27 01:00:00 MST 2002 nil irb(main):007:0\> p t + 3600 Sun Oct 27 01:00:00 MDT 2002 nil irb(main):008:0\> p t + 7200 Sun Oct 27 01:00:00 MST 2002 nil this looks like a bug! -a > **···** > > On 11 Dec 2002, Travis Whitton wrote: > > – > > ==================================== > > > Ara Howard > > NOAA Forecast Systems Laboratory > > Information and Technology Services > > Data Systems Group > > R/FST 325 Broadway > > Boulder, CO 80305-3328 > > Email: [ahoward@fsl.noaa.gov](mailto:ahoward@fsl.noaa.gov) > > Phone: 303-497-7238 > > Fax: 303-497-7259 > > ==================================== > > SIGSIG – signature too long (core dumped) ---
**Author:** ![Alexander\_Bokovoy](https://avatars.discourse-cdn.com/v4/letter/a/ecb155/32.png) [@Alexander\_Bokovoy](https://rubytalk.org/u/Alexander_Bokovoy)\ **Post date:** [11 December 2002 18:05 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/4 "2002-12-11T18:05:42Z")
Day Light savings turnover? > **···** > > On Thu, Dec 12, 2002 at 02:19:55AM +0900, Travis Whitton wrote: > > > I’m manipulating some dates, and I just found something weird. > > > > ruby -v > > ruby 1.6.7 (2002-03-01) [i586-mswin32] > > > > # works as expected > > > > irb(main):001:0\> Time.local(2002, 4, 29) > > Mon Apr 29 00:00:00 EDT 2002 > > irb(main):002:0\> Time.local(2002, 4, 29) + 86400 > > Tue Apr 30 00:00:00 EDT 2002 > > > > # weird behaviour > > > > irb(main):004:0\> Time.local(2002, 10, 27) > > Sun Oct 27 00:00:00 EDT 2002 > > irb(main):005:0\> Time.local(2002, 10, 27) + 86400 > > Sun Oct 27 23:00:00 EST 2002 > > > > So, adding the amount of seconds to equal one day to 10/27/2002 only > > brings it up to 23:00. If this is something completely obvious, please > > enlighten me. It’s causing quite a stir in my program… > > – > > / Alexander Bokovoy > > * * * > > As a computer, I find your faith in technology amusing. ---
**Author:** ![Ara.T.Howard1](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ara.T.Howard1](https://rubytalk.org/u/Ara.T.Howard1)\ **Post date:** [11 December 2002 17:40 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/5 "2002-12-11T17:40:09Z")
[snip] i guess maybe daylight savings time takes effect at 1:59 am, though that suprised me… i always assumed 00:00 -a > **···** > > On Wed, 11 Dec 2002, ahoward wrote: > > > On 11 Dec 2002, Travis Whitton wrote: > > > > [snip] > > > > > I’m manipulating some dates, and I just found something weird. > > > [snip] > > > > and even weirder : > > – > > ==================================== > > > Ara Howard > > NOAA Forecast Systems Laboratory > > Information and Technology Services > > Data Systems Group > > R/FST 325 Broadway > > Boulder, CO 80305-3328 > > Email: [ahoward@fsl.noaa.gov](mailto:ahoward@fsl.noaa.gov) > > Phone: 303-497-7238 > > Fax: 303-497-7259 > > ==================================== > > SIGSIG – signature too long (core dumped) ---
**Author:** ![David\_Alan\_Black1](https://avatars.discourse-cdn.com/v4/letter/d/278dde/32.png) [@David\_Alan\_Black1](https://rubytalk.org/u/David_Alan_Black1)\ **Post date:** [11 December 2002 17:48 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/6 "2002-12-11T17:48:41Z")
Hi – > [snip] > > > I’m manipulating some dates, and I just found something weird. > > [snip] > > and even weirder : > > ~ \> irb > irb(main):001:0\> t = Time.local(2002, 10, 27) > Sun Oct 27 00:00:00 MDT 2002 > irb(main):002:0\> 24.times do |h| > irb(main):003:1\* p t + 3600 \* h > irb(main):004:1\> end > Sun Oct 27 00:00:00 MDT 2002 > Sun Oct 27 01:00:00 MDT 2002 > Sun Oct 27 01:00:00 MST 2002 > Sun Oct 27 02:00:00 MST 2002 > Sun Oct 27 03:00:00 MST 2002 > […] > > irb(main):005:0\> p t + 3600 \* 1 > Sun Oct 27 01:00:00 MDT 2002 > nil > > irb(main):006:0\> p t + 3600 \* 2 > Sun Oct 27 01:00:00 MST 2002 > nil > > irb(main):007:0\> p t + 3600 > Sun Oct 27 01:00:00 MDT 2002 > nil > > irb(main):008:0\> p t + 7200 > Sun Oct 27 01:00:00 MST 2002 > nil > > this looks like a bug! I’m probably being completely thick, but what part of this looks bug-like? David > **···** > > On Thu, 12 Dec 2002, ahoward wrote: > > > On 11 Dec 2002, Travis Whitton wrote: > > – > David Alan Black > home: [dblack@candle.superlink.net](mailto:dblack@candle.superlink.net) > work: blackdav@shu.edu > Web: [http://pirate.shu.edu/~blackdav](http://pirate.shu.edu/~blackdav) ---
**Author:** ![Chris18](https://avatars.discourse-cdn.com/v4/letter/c/e8c25b/32.png) [@Chris18](https://rubytalk.org/u/Chris18)\ **Post date:** [11 December 2002 18:33 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/7 "2002-12-11T18:33:47Z")
[snip] i guess maybe daylight savings time takes effect at 1:59 am, though that suprised me… i always assumed 00:00 > **···** > > ----- Original Message ----- > From: “ahoward” [ahoward@fsl.noaa.gov](mailto:ahoward@fsl.noaa.gov) > > * * * > > Well, I think it happens _at_ 2:00 am (not 1:59). Ruby’s got it right. > > Chris ---
**Author:** ![Michael\_Campbell1](https://avatars.discourse-cdn.com/v4/letter/m/e274bd/32.png) [@Michael\_Campbell1](https://rubytalk.org/u/Michael_Campbell1)\ **Post date:** [11 December 2002 19:15 UTC](https://rubytalk.org/t/strainge-time-behaviour/3535/8 "2002-12-11T19:15:38Z")
> i guess maybe daylight savings time takes effect at 1:59 am, though that > suprised me… i always assumed 00:00 I thought it was 2:00 am.