Some “bouncing” , some refracting around the Earth. The WWV time signal that the ‘atomic’ clocks use is all “ground wave”, at least if you want the most accuracy. Coverage is at least 1500 miles. “Skywave” propagation can be farther but is not reliable ( or useful as a timebase . Now GPS is used for these applications commercially but kitchen clocks use WWV still). BTW the reason it is farther at night is related to the height above Earth of the relivant layer of the ionosphere. Solar radiation affects that
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