As the name implies, cold cranking amps (CCA) is a measurement of a battery's ability to start an engine in cold weather. The higher the CCA, the greater the power and therefore the better it is at starting an engine in cold weather.
However, it's important to note that CCA is only one factor to consider when choosing a battery. Other factors such as reserve capacity (RC) and amp hours (Ah) also play a role in how well a battery performs.
In general, you'll want to choose a battery with the highest CCA that fits your budget. However, if you live in an area with mild winters, you may be able to get away with a lower CCA since you won't need as much power to start your engine.