Yun has few ICs.
- Commercial: 0°C to 85°C
- Industrial: −40°C to 100°C
- Automotive: −40°C to 125°C
- Extended: −40°C to 125°C
- Military: −55°C to 125°C
ICs might be only Commercial grade unless premium paid.
Yun might failed at 7/24 outdoor environment.
How do I know which one I have?
Most likely is Commercial: 0°C to 85°C.
Drop a line to Yun ODM (Original design manufacturer)
Aluminum electrolytic capacitor:
Cold temperature with these capacitors can result in significant increase in ESR as shown in Figure. In this case, the resistance can increase as much as an order of magnitude at -40 C.