readme: add timezone disclaimer

README.org

@@ -49,7 +49,7 @@ Global variables must always include a location (section "Select Coordinates or
         ("Dubai, UAE" 25.0657 55.17128)))
 #+end_src
 
-A timezone is also often required ("Settings" > "Timezone").
+A timezone ("Settings" > "Timezone") may not be required, but be sure to set it because *the default one is UTC+0*.
 
 The current group is switched with =<tab>=. Each group's section has a set of variables that can be toggled on and off, such as temperature, precipitation, etc. Check out the [[https://open-meteo.com/en/docs][API docs]] if you're interested in the meaning of more esoteric ones.