Problems starting petrol engine from cold.

Hi having an issue starting the car first thing in the morning now that the temperature has dropped. The engine cranks over but really slowly and starts after about 5 seconds. When the temp dropped to about 8c last week it would not start at all, cranked over slowly and just stopped cranking, tried again and it again cranked over slowly and stopped cranking. Tried to use a jump station but no luck. Had to bump start it to get it to start.

I bought a new battery and im still getting the same results. although it has not failed to start since getting the new battery but on the other hand the temp has not been as low as it was on that day. Also once the car has started it has no issues at all starting for the rest of the day.

This morning the car started instantly with no issues but the temp was at 17c so the problem is only there at lower temperatures.

As i can rule out the battery what else could be causing the issue?

Thanks