With a reply like:
the weather was good enough for other students, so I could have flown if I really wanted to
I would say Whirlybird has hit the nail squarely on the head:
He may have been stressed because he's making no money due to this unseasonable March weather
Do not feel bad Garfs, yes it was no money for the instructor that flight. But how long did it take
you to earn that money to pay for the flight had you gone ahead?
It was not as if you had just not turned up (possibly the most annoying student habit)