***** NOT A TEACHER *****
My respectful suggestion:
How time flies! Ten years has passed in a twinkling of an eye. After college, each of us went their own way. Living in different parts of the country, we gradually lost touch.
1. I see no need to mention the seasons.
2. I said "Ten years has ...." instead of "have" because I am thinking of a period of time, but maybe others would prefer "have."
3. In 2014, it is a VERY good idea to say "Each of us went their own way" instead of "his own way." Since the 1960's, the use of "his" in such a sentence violates the desire to be gender-neutral. (Personally, the use of "their" in such a sentence drives me crazy, but most people here in United States are now accustomed to it and EXPECT it! Using "his" in a such a sentence would offend many people.)
P.S. Of course, if all your fellow graduates were male, then "his" would be appropriate. Furthermore, you could simply reword the sentence: "All of us went our own way."