Why is 'the' needed in the sentence?

We use the definite article (the) when referring to particular things or events, in this case the rain that was falling when we went out. We went out despite the rain, the heat, the fog, the wind, the snow.

Tang of course Con is right as usu; without the "the," he might be living at some location where it rains say 23 hours a day 362 days a year, in other words taken for granted

Thanks, contrex.