My colleague Jonathan McIntosh pointed me to Anselm’s discussion of God’s relation to time in the Monologion (available in Anselm of Canterbury: The Major Works). It’s a complex discussion.
On the one hand, the infinite nature cannot exist finitely (determinate) at a particular place or time, so it must exist everywhere and always, “in every time and place.” But it cannot exist in part in every place and time, since God has no part. But how can it exist whole everywhere and always? If it exists whole in every time and place, there must be as many divine natures as there are times and places. But if it exists in individual places as a whole at different times, then some places at some times will be non-existence, because without the divine nature nothing exists at all (quia sine ea prorsus aliquid non existit). God cannot exist as a whole at distinct times, then the divine nature is distributed over time according to the parts of time (per temporum partes).
Anselm resolves these puzzles by concluding that God exists both at every time and also at no time.
He exists in no time because he is not contained by any time: “If the usage of language permitted, it would, therefore, seem to be more fittingly said, that it exists with place or time, than that it exists in place or time. For the statement that a thing exists in another implies that it is contained, more than does the statement that it exists with another.” “In no place and time” does God exist, “since it is contained by no other at all. At the same time, “It exists in every place and time, because it is absent from none.”
He concludes, though, that, when appropriately qualified (quodammodo does a lot of work for medieval theologians), it is possible to say that God exists in time and place: “these properties of time and place can, in some sort, be ascribed to it, since it is just as truly present in all finite and mutable beings as if it were circumscribed by the same places, and suffered change by the same times.”