Bug 23734 - DateTime.Now uses incorrect month number for DST offset detection
Summary: DateTime.Now uses incorrect month number for DST offset detection
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 3.8.0
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2014-10-10 04:56 UTC by Oleg Gavrilov
Modified: 2014-10-10 04:56 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description Oleg Gavrilov 2014-10-10 04:56:44 UTC

From Sept. 26, when you call DateTime.Now, it will return time with 1 hour less. Then, if current date on machine will be changed to 27 Oct., DateTime.Now will return correct value. 

Steps to Reproduce:

1. On iOS 8, set timezone to +5 UTC Ekaterinburg.
2. Set current date on device to 26 September 2014.
3. Get current date and time like this: 
4. Compare time on device with output, there will be 1 hour difference (error).
5. Set current date on device to 27 September 2014.
6. Get current date and time, it will be equal with time, displayed on device.

Additional Information:
Tested in time zone +5 UTC Ekaterinburg (Russia) , on Mac OS X 10.9 and iOS 8.

My guess is that in DST logic, there is error when calculating current month (months are started not from 0)