Kenneth wrote:

I might try aiming some sort of space heater at the glass
for a while before doing the repair.

Even heating it slightly would lower the level of humidity
between the panes, and that would, in turn, lower the
temperature at which you would see condensation.

Heating air lowers the RH but doesn't change the absolute moisture content,
so the air would have the same dew point after it cooled.

We might dry the air by running a tube from a dessicant box to the hole
and cycling the space heater every half hour for a few hours to pump air
out and back into the window cavity.

Nick