Smile on
Definition 1 of 1
Pro Tip 1/3Positive Outcome
Used when something good happens, often unexpectedly. 
After weeks of rain, the sun finally smiled on our picnic day.
Pro Tip 2/3Idiomatic Expression
Not a literal smile but a metaphor for luck or good fortune. 
The weather smiled on the sailors during their voyage.
Pro Tip 3/3Impersonal Forces
Often paired with non-human subjects like 'nature' or 'fate'. 
Nature smiled on the crops this year, yielding a great harvest.