It is autumn now in Hanoi but it is still hot. I failed to wake up early (once) again and I will have to run under the sun. My skin darkens each time I wake up late. Asians prefer fair skin.
Note the use of verbs instead of adjectives: "darkens" instead of "darker" and "prefer" instead of "best". You will be using the English language more effectively when you learn to tell your stories with verbs instead of adjectives.
Seasons are not capitalized. You do capitalize days of the week and months of the year.