(one's) comfort zone

1. A place, activity, situation, or psychological state in which a person feels free from anxiety and is within their normal level of ability, experience, security, or control. Though it is often outside your comfort zone, traveling to foreign countries gives you a much greater perspective on how other people in the world live. The new job is a little out of my comfort zone, but it will give me a great opportunity to see what I'm truly capable of. Going on a blind date is definitely not in my comfort zone, but I'm tired of being alone.

2. The temperature range wherein one's body feels naturally comfortable, being neither too hot nor too cold. Many retired Americans, being more sensitive to the cold, settle in Florida, where the balmy weather better suits their comfort zones. Thank you for turning the heat up—this is more like my comfort zone. A: "I think Tammy's internal thermostat must be broken." B: "I know, her comfort zone is way colder than mine, which is a problem, since we live together!"