Since June of 2016 I have been logging atmospheric pressure using a Raspberry Pi B+ and STEVAL-MKI165V1 evaluation module which features the LPS25HB atmospheric pressure sensor. The Raspberry Pi uses a small Python program I wrote to log the pressure data and time to the system SD card and also plot the past 24 hours of atmospheric pressure. It has been interesting to observe the changing pressure theses past few months but that is not the reason for this post. The Pi is setup to use my local time zone which is EST and on November 6th 2016 daylight saving time ended for the year. This caused the Pi to set its clock back one hour and created this interesting discontinuity on the resulting pressure plot at 2:00am-1:00am on November 6th. It is not a problem for my simple data logger but it got me to realize how important it is to think about the effect DST may have on any data logger/controller I have in the future.