What is the problem with cold starting?
The cold starting is nothing but an attempt to start an engine that is at far lower temperature than its normal operating temperatures.
Let's find out what is happening at lower temperatures:
The viscosity of engine oil increases with reduction of temperature
The petrol/gasoline when passed into the cylinder will fail to vaporize and will condense as a dribble on the walls of the engine block and flow downwards.
So, when the starter motor engages, it has to move the crankshaft through the more viscous oil bath and as the petrol is not vaporizing at these lower temperatures readily, it becomes difficult to ignite the fuel.
Finally, with more and more revolutions of crankshaft the engine heats up and the engine starts.