Hi, You don't give the time zone but this is probably due to the clock jumping by one hour when switching to summer time. In UK this happens at 1am and on that day there is no such thing as 01:05, etc., see eg https://www.timeanddate.com/time/change/uk/london In your time zone this probably happens at 2am. Georgi Boshnakov ------------------------------ Message: 7 Date: Thu, 26 Jan 2017 11:02:06 +0100 From: rob vech <rob.vech87 at gmail.com> To: r-devel at r-project.org Subject: [Rd] strptime bug Message-ID: <70325e6b-6d54-8172-3915-bbfc8d5cd837 at gmail.com> Content-Type: text/plain; charset="UTF-8" Dear developer list, I want to submit the following problem that seems like a bug, as confirmed by an other user [1], related to date-time parsing: Here a simple script: # that works: as.numeric(as.POSIXlt(strptime('2016-03-27 01:05:50', format='%Y-%m-%d %H:%M:%S'))) # that not (it returns NA): as.numeric(as.POSIXlt(strptime('2016-03-27 02:05:50', format='%Y-%m-%d %H:%M:%S'))) # it works again as.numeric(as.POSIXlt(strptime('2016-03-27 03:05:50', format='%Y-%m-%d %H:%M:%S'))) I made several test and the problem seems to be related to the couple "2016-03-27" as date and "2" as hour. It seems not to be related to the datetime format. There is a similar bug on bugzilla [2] but in my case I cannot replicate it. My OS is Win 7 and R v3.3.2. Thank you rob [1] https://stat.ethz.ch/pipermail/r-help/2017-January/444468.html [2] https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16764 [[alternative HTML version deleted]] ------------------------------ Subject: Digest Footer _______________________________________________ R-devel at r-project.org mailing list DIGESTED https://stat.ethz.ch/mailman/listinfo/r-devel ------------------------------ End of R-devel Digest, Vol 167, Issue 23