How do I clear the WSO100 outside humidity offset using Maretron’s DSM150 or DSM250 display?

You clear the WSO100 outside humidity offset using Maretron's DSM150 or DSM250 display in the following way:

1. Enter menu mode, scroll to "Configuration…" and press < Enter >
2. Scroll to "Device Configuration…" and press < Enter >
3. Scroll to the row containing the WSO100 and press < Enter >
4. Scroll to "Reset Factory Defaults" and press < Enter > twice.

Beware that resetting factory defaults resets all settings back to factory defaults, not just the outside humidity.