Is it possible that our metal gate could be expanding in the hot summer weather? It has been well over 100 degrees daily on average for a month or so, and for some reason a metal gate we have had for years is not closing properly because it's just too big for it's gateway.
It is possible and should be relatively easy to estimate how much it is expanding based on the coefficient of thermal expansion, the size of the gate and how hot the gate gets.
One other issue you might to look at is movement of any posts supporting the gate. If you have had unusually dry weather for instance this may have caused the ground supporting any posts to move and that could cause a similar problem.