This morning, my husband became grumpy and even a little angry with the local school district for not closing schools. About six inches of snow fell from Saturday night through daybreak Monday. Roads were slick but drivable. Temperatures were in the single digits. Given those conditions, he figured there was no question of whether schools would close. They just would. On the other hand, I figured with those conditions, there was no way they wouldn't open.
When it comes to weather and school closings, my husband and I come from different backgrounds and therefore have different expectations. He's a Virginia boy, and anyone who lives in the South knows that schools districts declare a snow day if there's even a threat of snow. I grew up in the Denver metro area (which is where we now live), where it generally takes at least a foot of white stuff on the ground before the kids get to stay home.
Our differing expectations resulted in different reactions to what happened. He was disbelieving and angry. I kind of shrugged and went back to sleep. (When we lived in North Carolina, our positions were reversed: I was often disbelieving when a half-inch of accumulation closed the schools and caused a run on every grocery store in town for break, milk and canned goods.)
So what does this have to do with writing? Characters, like real people, are the products of their experiences, which then affect how they form expectations for any given situation and their reactions to the outcome. You don't have to tell the reader that one character grew up in a warm climate and one character in snowy climes, but you can show it through their differing expectations of what should happen in a snowstorm and their reactions to what does happen.