"I do not like rainy weather."
Translation:لا أُحِبّ اَلْطَّقْس اَلْمُمْطِر.
if you are trying to put "a" before "rainy weather" it might be wrong (I did it before in other languages and it was marked wrong) - This is because in English the word "weather" is not counted (it does not get "A" before it, but only "the"). So, you can't say a nice weather in English, in general.
However, in such instances where in English they speak of "general" item which does not require a definite or indefinite article (like the example above, rainy weather), in Arabic, such example is not followed and mostly the word would come defined EVEN if it is a general aspect. Like, my classical example of such aspect, I love nature. Nature here points to the general aspect of "nature" - However in Arabic, the typical translation would be أحب الطبيعة and not أحب طبيعة; it would be meaningless to leave طبيعة without the definite article AL.