Life's Little Mysteries

Life is, of course, full of things we don't understand. Things like what's inside black holes, the nature of time, and why toddlers emit ear-splitting shrieks when excited.
At the moment, I am baffled as to why, in late May, Pittsburgh continues to experience such chilly weather. My recollection is that usually Pittsburgh goes from frigid to roasting in the space of about a week, and that this occurs sometime in April. When last I lived here, I concluded that T-shirts and long-sleeved shirts (staples of my wardrobe in Northern California) were nearly useless here because it was always either too hot or too cold for them and you went from turtlenecks and heavy sweaters almost directly to sleeveless tops.
This year, however, is determined to be different. Apart from a few warmer days here and there, we keep having days that start off around 40 and struggle to make it past 60 degrees. Add on the tendency toward rain, and I feel like I'm living in Britain. I'm all for the lush greenery and the flowers, and I don't mind a fair amount of light rain, but I'd like it to warm up just a few degrees and refrain from sprinkling during the times when I might want to bike to and from school.
Another mystery is that of today's email from a former student. I am happy to hear from former students, but I would prefer them to give some explanation why they are contacting me, beyond a vague desire to "keep in touch." I suppose that a simple desire to keep in touch would suffice coming from students I have actually gotten to know very well (or even whom I didn't know that well but who were outstanding students or who I directed to seek counseling) but when all I really remember about the person is his/her name and that they were in a one-credit class I taught around six years ago, and all they say is that they'd like to keep in touch, well, I can't help wondering if they even remember who I am and are confusing me with some other acquaintance in an ancient address book. I mean, why not at least say "I was in your BLANK class in BLANK year. Even though your class was a requirement, I enjoyed it and have fond memories of your (wonderful/stimulating/peculiar) lectures. These days I'm (working/traveling/in jail)." I could then say something like "Nice to hear from you. I enjoyed teaching your class. I'm still in Pittsburgh and getting ready to teach X, Y, and Z. I hope all goes well for you in your work/family life/travels/penal servitude." Of course, the better I know the student, the more personal my response will be. But I know that I could have made a difference even to people I don't remember very well, because there are certainly people who made a difference to me who are unlikely to remember much more than my name or face.