barometric pressure and baked custards

[phlawless]

i recently made some baked custards that curdled well before they usually do...my employer explained that barometric pressure can shorten the bake time on these things...is this true?

[Harold McGee]

I think it would take a pretty strong high-pressure front to make a significant difference in boiling points and baking times. Was the milk as fresh as ever? The oven temperature consistent? I would suspect those factors more than the atmosphere.