Worn as the final outer layer, a cycling jacket can be deployed to face off with any one of hundreds of different weather conditions. Wind, water, freezing temperatures, it's fair to say that there are as many varieties of bicycle jackets as there are riders. Bearing that in mind, let's narrow things down and provide some advice.
There are two types of rides in the rain. The first is the rain all day ride, and here some serious protection is required to combat moisture ingress. The other ride is sometimes the hardest to prepare for, and this is the intermittent rain ride. We would recommend a more packable solution for these rides, something that can be put on quickly and easily, or removed and stored in a rear jersey pocket. Try anything with 'Light' in the name, making sure to check the product's attribute icons to ensure it is fully waterproof.
For 90% of rides, a windproof cycling jacket teamed with a base layer and/or jersey is all the protection you need, and will significantly contribute to your on the bike enjoyment. By nature more breathable than their full rain protection counterparts, most windproof cycling jackets come with basic 'get me home' shower protection. Remember, always choose the product that suits your needs and be sure to check the product page carefully to see an item's detailed features.