Last fall I felt bad for a sad Geranium that failed to thrive so I dug it, stuck it in a 6" pot and kept it very dry on a windowsill all winter. As soon as temps were above freezing I put it outside in rain and flurries.
It's going crazy now with tons of blooms. I think because they are true perennials they really benefit from stark seasonal changes.
Edited to add: I also agree with Loretta, it has a lot to do with the cutting. Or whether it's a seed Geranium vs Cutting Grown .
