Parallel
Numbers 9:21
Brenton's English Septuagint · Berean Standard Bible
And it shall come to pass, whenever the cloud shall remain from the evening till the morning, and in the morning the cloud shall go up, then shall they remove by day or by night.
Sometimes the cloud remained only from evening until morning, and when it lifted in the morning, they would set out. Whether it was by day or by night, when the cloud was taken up, they would set out.