Agree tiny shot of starting fluid will let you know a lot about firing, but sounds like just a simple battery or solenoid switch needs to be cleaned or replaced. New spark plug never hurts but usually not needed.
I recently had to replace the battery and solenoid on one of mine cold weather gets one every time.
X2 what Ridgeway said, check that battery and connections and then again. Clean any spec of corrosion.. Maybe that resolves it,, easy to determine fire, fuel air issues..
Be safe and keep us posted, good luck.