Saturday a little sun may be peeping out in Minnesota. But Sunday it's back to the usual for these days: cold and rainy. Rain, shine or snow, Nanci Olesen will be going for a swim in Lake Harriet in Minneapolis. Last year, she swam every day until November as a dare to herself. This year, the ritual has become much more important. We find out why.

More Thoughts from Producer Nanci Olesen:

I told a friend recently that it is surprising what a person can get used to.

My sister Amy is so sweet, so cheerful in the face of her cancer. What throws me off is that the actual location of her tumor is in the place in our brains where we process emotions. So she is not able to fully take in what is happening to her. To the degree that she does take it in, she can't react the way she used to. That deep emotion is unavailable to her. That is what I grieve so often. I am lonely for the Amy that I used to know.

It's hard to tell this story publicly. Sometimes I wonder why I am compelled to do so. Perhaps it's because I feel that I can connect to others who have gone through something similar. Perhaps by telling it I am trying to explain it to myself.

Our weekends of taking care of Amy's kids are becoming normal to us. I have a cupboard in the kitchen dedicated to sippy cups, bottles, baby food and little spoons and forks. Just like I used to years ago for my kids. We have a Portacrib, a high chair and a few toys. We store all this stuff in the basement during the week. Our kids, ages 12, 13 and 17, are used to having their cousins at our house. They take turns taking care of them. It is sweet to see our 17-year-old son holding his little 10-month-old cousin and giving her a bottle. Our daughters are so into the rhythm of being with the little kids that they make an effort to be around to help.

I don't want any of this to be happening to us all. But in the midst of it, we are finding how to cope and even how to thrive. My mom always stresses that we are just taking one day at a time. We truly are learning how to do that.

Sometimes I don't feel like swimming in the lake at all. It's been getting cold in Minnesota, and the lake water is about 48 degrees now. But there is something about the bracing cold and the deep exercise that keeps me coming back. I have told myself that I have to do this until November 4th. Yesterday I swam in the pouring rain.

That whole idea of truly living for today is what I have learned from being in the thick of my sister's cancer.