The maximum and minimum temperature for the day is determined in this example logic group.
The logic group receives the measured temperature value via the "Temperature sensor" input.

The current minimum and maximum temperature values are output via the "current min temperature" and "current max temperature" outputs.
These values are updated after every hour.

With each new day (date change), the minimum and maximum values are taken over and output via the separate outputs "yesterday's min temperature" and "yesterday's max temperature".

Note: The resolution of the measuring interval for the temperature is hourly. This means that the current temperature value is always used for evaluation on the hour.