Re-reading the OP to be fair I don't think there's any implication that the material which roads and vehicles are made up of become malleable during the summer months. (although if it got
really hot the asphalt might soften up a bit).
The point that was made was that due to less icy conditions and longer daylight hours the risk of hitting these things becomes low enough for the OP to be happy to ditch the helmet.
Just thought I'd clarify as you sound a bit confused
Not far off the mark Paco

...i should have qualified my logic...not that i have to, but helmet discussions inevitably wander off into far flung scenarios..
A general way of putting it..
1. i dont give a monkeys what anyone else does.
2. I neither condemn nor applaud anyone who wears..or doesnt.
3. I'm 52, have ridden a bike for 40 plus years, never been knocked off, only ever fell off twice (AFAICR)
4. Only worn a helmet for the last 2 years...why did i start, i don't know, just seemed a good idea.
5. I only (generally) wear in the winter, simply on the (perhaps wrong) logic that the probablilty of having an off in ice is greater, and 90% of my riding is done in the dark, where i assume (only assume) there's a greater chance of not being seen.
In simple terms, poor lighting and icy roads are MY logic for wearing. I feel safer...whether i am or not i can't control.
Neither apply right now, hence my abandonment of the helmet.
No hidden agenda, no flag waving anti or pro helmet opinion....just a statement of where i am, and did anyone feel or do the same.
I shoulda known better ...
Just remembered, i do remember why i started wearing...a guy at work was knocked off one dark night in winter, the cars wheel arch dented his helmet. After that incident, it (like insurance) makes you think the worst, so i went and brought one.