This can be done using Graphical Analysis Pro or Logger Pro.
This cannot be done using the free version of Graphical Analysis.

In Graphical Analysis Pro and Logger Pro, you can display a meter for any calculated column. To show a meter that displays the maximum value obtained by a sensor during data collection, you need to use the function max(X) as the expression for your calculated column.

Note: This same method can be used to create meters for any statistic that creates a single value in your data table, such as minimum [min(X)], average [ave(X)], and standard deviation [stddev(X)].

Graphical Analysis Pro

1. Launch Graphical Analysis Pro and connect to your sensor.
2. Click or tap the y-axis label to display the Plot Manager.
3. Click or tap the three-dot icon, , next to the sensor column name, and select Add a Calculated Column.
4. Enter a name and units, and adjust the displayed precision as desired. Verify the Metered option is selected.
5. Click or tap Insert Expression, then click or tap Custom Expression.
6. Enter the expression max(“X”), where X is replaced by the name of the column showing the sensor data.*
7. Click or tap Apply to create the calculated column.
8. To display the meter, click or tap View Options, , and turn on Meters.

Logger Pro

1. Launch Logger Pro and connect your sensor.
2. Choose New Calculated Column from the data menu.
3. Enter a name, short name, and units.
4. Enter the expression max(“X”), where X is replaced by the name of the column showing the sensor data.*
5. Click or tap the Options tab and adjust the displayed precision as desired.
6. Click or tap Done to create the calculated column.
7. To display the meter, choose Meter > Digital Meter from the Insert menu.
8. Choose Auto Arrange from the Page menu to optimize layout of the screen with the new meter.

^* For example, if your sensor column name is Temperature, the expression would be max(“Temperature”).