watering after rain

First off, I appreciate the lawn care knowledge I have learned from this forum, and especially the reading on organic lawn care for the lazy.  I still have a question though, if watering after a rain is strongly recommended and a small amount of precipitation actually accumulates (less then .1") combined with the fact that the lawn doesn't need the water (although it's not wet by any means) what should be done?  I really don't want the .1" to feed only the weeds, meanwhile I don't want to water if the grass doesn't need it. 

Thanks!

If the lawn doesn't need the water, then don't water!  Easy peasy!

I was hoping you'd say that