Rainfall accumulation map
Inches is selected but map reports in mm
Directions to set Main Menu Settings to your desired preference.
For this answer, I'll assume you are using an Android or iOS app and the main settings are in mm. Here is the process to change Main Settings to inches. The pictures are screenshots of my iPhone X but any Android phone should be similar.
First, click on the current layer icon to get to the Main Layer Menu.
Next you will see the Main Layer Menu.
Scroll the menu all the way to the bottom and click on Advance Settings.
You will then see the general Setting Menu.
Make sure the items in the red box are set to inches for Rain and/or Snow. Set any other general setting you wish to change. When you exit the Main Menu, all will be saved.
On the web version (don't know about the mobile apps) those settings are ignored by the rainfall accumulation layer and it always defaults to inches until you click on the scale in the bottom right. The rain settings only affects the rain/thunder layer.
I just opened Windy in my browser and changed my accumulation scale to mm.
Then I set my overall setting to mm for rain.
I closed the Windy tab and reopened it fresh and my settings were still both mm.
Then I left settings in mm but changed the scale to inches, closed and reopened Windy and Windy remembered both settings. Could this be browser specific? I am using Opera on a Mac. What do you use?
There is not an issue with it failing to save them - it is the fact they are two different settings and one of them appears in two places that is confusing:
The units for rainfall can be toggled by clicking the scale on the rain layer, and your choice is also shown / can be changed in the settings panel.
The units for rain accumulation can be separately toggled by clicking the scale on the rain accumulation layer, but this setting is not shown in the settings panel
Either it should be consistent and show both choices in the settings panel, or (and i think this is the better option), have a single setting affect both the rain and rain accumulation layers. What use case is there for someone who wants to see rainfall in mm and rain accumulation in inches?