Operating Temperature of MEGA 2560 rev 3

What is it operating temperature of Mega 2560 rev 3 board?
We have an outdoor project in Montana, USA so we are hoping the Mega uses -40C to 85C industrial grade components.

You may want to look at a "ruggedised" Arduino

They can be had from here

I asked a similar question about my MKR1000 but have not yet received a response as it seems to go flakey at around minus 4 degrees C'

I think I need to get the BOM to see they are rugged.
Even Rugged MEGA — Rugged CircuitsRugged Arduino
show only -10C to 85C

They said the new one goes minus 40.

I live in Montana and the cold weather here can be brutal. LCD's will freeze up in our winters. I recommend you include a heater in your enclosure to keep the temperature up and condensation low.

For low temperature displays you should use OLED rather than LCD. Most are rated down to -40 C.

Rugged Circuits' has extended temperature Ruggeduino products. I've also looked at Waspmote, which is rated -30 C apparently. Are there any other Arduino boards out there that are rated to -30 C or -40 C?

You might be surprised at the stock Arduino capability.

Had an MKR1000 outside over winter (last two) and the DHT connected to it was the component that failed.
Lowest recorded temp before the sensor failed was minus 37`C
Board is still in regular use.

The only protection the board had was a thin plastic lunch box and that had two holes in it to let the cable in and out so certainly not airtight etc.