Why does so much condensation form under my pergola?

Question

It drips onto whatever is there.

Is there a way to stop or greatly reduce it from happening?

Answer 1

not enough ventilation and air flow

Answer 2

Without a heat source or a/c unit you should not have any difference in temperature except for a few minutes when the sun comes up. This could warm the roof quicker than the underside, especially if you have a metal roof. Do you have a metal roof on it?

Are you sure it is not morning dew dripping off the edge of the roof?

You might try a ceiling fan with the switch flipped to where it pushes air up and not down.

Is it in partial shade and then goes right to being in the full sun?

Usually you need a big temp variation to form condensation on the underside of a roof.