Slow Start on 2004 Scion xB

In cold weahter my car takes an longer to turn over than it does in the summer months. it is about 4 seconds to the less than 1 second in the summer. Should i have the altenator or battery replaced, they are both original to the car?

Asked by for the 2004 Scion xB
get the battery checked first. the colder it is outside, the less power it has. in the real cold weather, you really need a good battery to spin the motor over at the right rpms to get it to fire off right away.
battery test is very easy and is free in a lot of shops.

1 more answer
Mine did the same, I checked the battery, got 100% charge. I don't think you should worry.