Need help with a script to calculate time, minutes and hours

I would start by figuring out how you will record the temperature differences. Once I resolved that, I would start to work on the time calculations.

I would create a start temperature and end temperature field with the numeric format and either 1 or no decimals. Then I would create a field to hold the temperature difference. This field's value can be calculated by either using the "Simplified Field Notation" or the "Custom JavaScript calculation" options.

The time calculations will require the "Custom JavaScript calculation" option since the "Simplified Field Notation" method can not perform the necessary conversions.

The practicalPDF Date Library for Adobe Acrobat : http://practicalpdf.com/the-practicalpdf-date-library-for-adobe-acrobat/

This is very similar to a time sheet calculation for the time worked in a day. You have a start time and end time and you need to calculate the difference between the two events. Most time sheets calculate only the times that occur within a single day but you may encounter an event that occurs on a different day. You also, just like on a time sheet may have an interval that spans the period in which there is a change from Day Light Savings Time or Summer Time where there is a jump forward or backward of an hour. So your calculation will not be a simple subtraction of the start time from the end time. The number of minutes go from 00 to 59 and then the hour changes and the hours go from 00 to 23 and the day changes. Days are a whole set of other issues because of the varying number of days in a given month. Fortunately JavaScript assigns a unique value to each millisecond beginning at January 1, 1970 00:00:00.000, midnight. So there is a unique ascending number for each millisecond in JavaScript's date object. So your task is to convert a date and time string value into a JavaScript date object for the staring date and time and the ending date and time. When you take the difference in milliseconds between these two values you will have the number of milliseconds in the measured interval. It is a trivial computation to convert the number of milliseconds into minutes or hours.