There are those who say that atheism is a worldview. I disagree, because atheism only covers one stance on one issue: it only says I don’t believe in a deity of any sort.
However, the fact that I’m an atheist does affect certain parts of my worldview. For example, because I’m an atheist, I feel more responsibility to take care of others as much as possible, as a god who does not exist cannot help. It is, of course, possible and common to reach the idea that one has a responsibility to care for people from a religious foundation, but it is just as possible to think “god will take care of it”.
Atheism also affects my morals. Because I don’t believe in a god who could be offended by certain actions, I can no longer see a moral reason to avoid things like masturbation. It hurts nobody, unless one is in a relationship wherein it is preventing or harming intimacy.
My moral basis, rather than being “don’t offend god, do as he says”, has become “Cause no harm, suffering is bad, pleasure is good”. I still agree with the golden rule “Do unto others as ye would have them do unto you” as much as I ever did. (I have encountered a situation where I followed that rule and it was apparently the wrong way to act.) My moral decisions are now based as much as possible on empathy, rather than following the rules of a church.
My worldview is also informed by science, in that I see the world as a cosmos because that’s what science tells us. I see evolution as true because that is where the evidence points.
In general, however, my worldview boils down to this: There are a lot of people, many of whom have conflicting interests. A few might be jerks just for the sake of being jerks (Cruella from 101 Dalmatians is just sort of evil), but for the most part each individual mostly wants to do the right thing most of the time. Even the times when people fail utterly to do the right thing, it is often that they are misguided or chose a selfish “me first” approach over a “them first” approach. I don’t see anything morally wrong with refusing to share your dessert with a friend who could afford a meal, although it is clearly morally superior to share if the friend wants some. Similarly, it is hard for me to see having one’s own child as morally wrong, but it is clear that adopting one of the millions of orphans is morally superior.
Realizing that I thought this way helped me turn away from conspiracy theory thinking. If everyone is trying to do what is best for themselves and probably everyone else, too, why would there be a huge conspiracy to harm most of the world’s population? How would it be kept so secret?
Just some thoughts. Do you think humans try to act morally most of the time?
The Complete History of the Universe: A Personal Journey 
I would suggest that atheism is a worldview because it is a bucket that catches a lot of attitudes and behaviors such as a questioning mind.
Morality is a subjective judgement against a set of rules, and often those rules are less clear cut when you look at them.
Atheism is not a bucket; it is one answer to one question. Atheists vary wildly in attitudes and behaviors. I can hardly be said to have a questioning mind when it took me so long to see through creationism, for instance. There are atheists who are liberal and conservative who have good and bad views of humanity. While skepticism tends to be strongly associated with atheism, saying that atheism catches skepticism is getting the causation backwards. In most cases, it is skepticism which causes atheism, so it is more accurate to call skepticism a worldview than atheism.