Many nouns that end in -o are masculine. Many nouns that end in -a are feminine. However, there are certain Spanish nouns that end in -ma that are masculine. It is important that you not over-think this. A mistake that many language learners make which slows their language growth is trying to figure out “why” on everything. Some things you simply need to accept and memorize. This list is one of those things:

the program | el programa
the problem | el problema
the drama | el drama
the system | el sistema
the charisma | el carisma
the symptom | el síntoma
the aroma | el aroma
the climate | el clima
the trauma | el trauma

Like I previously stated, this is a list of nouns and their genders which you must simply memorize. A common mistake that Spanish learners make is assuming that just because the Spanish noun ends in -a, it must be feminine. Don’t assume. Consistently learn and improve your Spanish.

I have a friend in Japan who learned English 17 years ago in the United States. She attended high school and college in the U.S. She now has a very good job as an assistant and translator for a large company and gets to travel all around the world. She has very good English, but she still makes mistakes. After 17 years of learning and improving her English, she still works hard to correct her mistakes. She has been very successful because of that. Don’t be afraid to make mistakes. Laugh about them, learn from them, and move on.