It was sunny and almost 70 F at work yesterday, but my ride home required stopping to put on a long sleeve shirt due to very cool breeze off Lake Ontario. My timing was perfect, arrived at the lift bridge just as it lowered and the gates were going up. As I crossed the curb from bike path to 4 lane road with 2 lanes of choked traffic, my lunch bag fell off my rack and my rear blinkie fell off. It was a quick scramble to pick things up and get going again, but I made it before the traffic from the other side of the bridge got there. Then once I got away from the lake, it was too hot for long sleeves, but didn't stop, just rolled up the long sleeves.
I've removed my panniers for the summer, bought an 11 litre rack pack at MEC, found that I usually have about 12 litres worth of stuff. That's why my lunch bag was on top of the bag on the way home. I now spend considerable time jamming and stuffing before leaving. I guess I'll be looking for a rack bag with more volume.