Is it possible to get the maximum/minimum temperature range in one single day?
Again, not understanding exactly what you are looking for, you can check out a few things.
First, a report is automatically generated every night at midnight that shows the high and low temperature for very hour of the just-concluded 24 hours. It is called the WeatherCatDailyReport and you will find it at ~/Documents/WeatherCatReports as a PDF file on your local hard drive.
Second, WeatherCat | Tools | NOAA Style Reports | Monthly | April | 2015 will show you the minimum and maximum temperature for each day of the month and what exact time those temperatures occurred.
Third, WeatherCat can be set to email you a message at midnight, showing what the temperature was for every minute of the just-concluded 24-hour period. In other words, it will email you a table with 1440 entries, one for each minute of the 24 hours, displaying what the temperature was during each 1-minute interval of the day. This is set in WeatherCat | Preferences | Email |Daily Data Email.
Hope this helps.