Hi Yuki, --> Even if it rains, I will go out. --> I went out even though it was raining. Even if can be used for present and future, even though can be used for past and present.

Even though is used to introduce a condition which currently is true, so both sides of the statements are facts: FACT even though FACT Even if = introduces a hypothetical condition that is not yet true, so the first statement is true, but the second statement you are not sure about or it hasn't happened yet.: FACT even if NOT YET TRUE たとえば：　I will go to work even though I'm tired. (仕事に行く。そうして、疲れた。二つのは本当・じったいです。You are going to work and you are tired. Both are facts.) vs. I will go to work even if I'm tired (仕事に行く。でも、疲れるのことが分からない。You are going to work, but you are not sure if you will be tired.)