If one is saying there "might be" a God, then he/she is not an Atheist, but an Agnostic, The saying that their "might be" a God, no matter how unlikely you think it is, means some small part of you is still open to the possibility, making you Agnostic...
On the other hand an Atheist is not open to the possibility that there could/might be, or is a God AT ALL, and claims they know this with absolute 100% percent certainty, and some even claim that they can even prove that there is no God, which from my perspective is neither provable nor un-provable, so..
Anyone claiming to be an Atheist that is in, no matter how minute of a measure, even slightly open AT ALL, in any kind of measure is not Atheist, but Agnostic...
I would like to quote a line from Data from Star Trek, when asked about an astronomical phenomena they encountered, he was asked about it "What do your sensors indicate?" Data said "Nothing sir." To which Data was asked "Nothing?" to which further was said "Mr.Data, you must mean that it's empty of matter... There's always some form of energy at work." To which Data replies "Sir our sensors are showing this to be the absence of everything... It is avoid without matter or energy of any kind." To which Riker then says to Data, "Yet this hole has a form, Data, it has height, width..." To which Data replies "Perhaps, perhaps not sir."
To which Picard says "That's hardly a scientific observation, commander." To which Data replies "Captain, the most elementary and valuable statement in science; the beginning of wisdom is, "I do not know"" Then he says "I do not know what that is, sir."
And I believe we are inevitably led to the same conclusions about God, saying "I do not know", unless we have proof (and I personally do and have, for me anyways) but I do not blame others who do not have proof or for being Agnostic in their position, but I do believe strict Atheists to be wrong however, for they are not saying, "I do not know" But are saying for, and with absolute certainty that "know" for 100% solid fact that God does not exist, which cannot be proven and is therefore invalid and unreasonable and not logical (to me anyways)
God Bless!