Temperature threshold for electronics components
Depends on your end application and life time requirment.
https://en.m.wikipedia.org/wiki/High-temperature_operating_life 

We do testing at elevated temperatures around the temperature you have quoted for just few months to assure about the life time of the product.  It means, we are already stressing the product and the components.  

  

Depending on the expected life time of the product you can plan.  See the operating temperature of all th devices on board, especially the displays and capacitors.


For example, a super capacitor at that temperature range won't even hold half the charge it would at room temperature, at a slightly higher temperature, it will fail permanently.  
The rating of the devices come down with higher temperature. Power rating for resistors, capacitance for capacitor for example.  
The diodes will have derated forward current and elevated reverse leakage currents