I don't know how the weather predictors act in your area, but it seems like when there is ANY hint of the temps dropping to freezing within 100 miles of them, they start interrupting regular programming. If you are watering with normal water, unless you have something of a hard freeze, I would expect the water to actually help keep the grass warm by providing more thermal mass before freezing the roots.

My inclination would be to water 3x per day until 80% of the grass is germinated (another week?). Then water more deeply and less frequently. Say once a day for 20 minutes (assuming you were watering 3x per day for 5 minutes to get the seed started). Keep that up until the grass is 3 inches high. Then stop watering a few days to allow the surface to dry some and mow it back to 2.5. Depending on where you live, that might be your last time to do anything on the lawn. If it freezes between now and 3 inches high, it will stop growing and you can stop watering.