The weather in Hanoi has been changing constantly. Several days of heavy rain gave way to scorching heat, followed now by light rain and cooler air. This I like the most of all, though it be wet outside. I do not understand you used of "marked". My use of the subjunctive mood in the last sentence is a bit old-fashioned. It would be more common to say "though it is wet outside". However, I like "be wet" because it sounds poetic.

The weather in Hanoi has been changing frequently. It was marked with heavy rain for several days then it became scouching hot and until now, it has been lightly raining while it is much cooler. I like this weather the most even though it is wet outside.

The weather in Hanoi has been changing all the time. It rained heavily for several days then it became scorching hot. And now it has been lightly raining and it is much cooler. I like this weather the best even though it is wet outside.