In the chart below time values 2 and 3 are 21:46 and 00:10 and should be displayed around a middling value. I would like to set the y axis minimum and maximum to something like 19:00 and 05:00 the next day but cannot make excel do it. It seems you cannot set axis maximum at a lower value than the axis minimum. I even tried setting the minimum as a negative value which didn't work. (I have it as a line chart because it is more clear how the points are related than a scatter plot). Any ideas much appreciated. Failing a proper solution I wonder if I could make it work by a adding a false date - pushing all the data before 09:36 into the next day, but don't know how to make a date time number format like dd:hh:mm work ? Plus it is laborious as I would have to type in all the false date data.