How do you know if you need to water the lawn?

[Nikia]

We have never watered our lawn. We have only lived here two years and the place where we lived before was watered by the landlord occasionally.
It has rained once in the past few weeks and has been pretty hot the past week. The grass is brown in the areas of the lawn that aren't shaded at all. I'm not sure if it will rain anytime soon.
I don't want it to grow. My husband is gone for a couple more weeks, and I'd rather not mow the lawn (being in my third timester of pregnancy with it being hot). I don't want it to die either though.
I'm not sure of the species composition although there appears to be at least a few different species. The soil is somewhat sandy. It isn't baking hard like the clay soil from the area where I grew up. I live in Central Wisconsin.

[ldr65]

1. It should be OK

Even though it may look all brown and dead now, as soon as it gets some rain on it it will green up again. I live in TN and we are in a drought pretty much and the grass is brown. But last week it rained some and the grass is green again.