Maui Surf Spot Map.

Maui has some of the best surf in the world. During the winter months the north shore cranks so definitely stay to the south shores.

In January you will need to stick to the breaks south of Lahaina and also the ones south of Kihei, anything facing north will be too big, unless you find a protected inside reef reform.

Be aware that all north facing breaks will be subject to big swells and have a lot of water moving around. Be also aware that during the winter swell season, most people keep their radios dialled into surf report all day, as swell size can increase half hourly. You also need to expect freak sets up to 3 times bigger than your average set waves. So it does get quite dangerous in the ocean in Hawaii.

Maui's safest place to surf for beginners are the breaks south of Lahaina, starting from the Lahaina breakwall which is a superfun wave breaking left and right on reef.

It's advisable not to go out at Honolua Bay in January. It's a highly localised spot, the entry and exit isn't easy and the wave has got many sections and curves horseshoe like around a reef, you can get into trouble here even if you are an experienced surfer. It's very very crowded and the level of surfing there is insane.

Maui is heaps of fun for beginners, even in winter, you just need to find out where the swell is coming from and then go to the other side of island that is protected, it will be plenty big enough for you. There are some really fun waves in Hana to be had (if you have a Northwest Swell).
Just ask the locals and lifeguards when you are there. They will tell you where you are ok to go.

There is a local guy at the parking lot south of the Lahaina breakwall who rents really cheap boards, he has a lockable trailer on the parking lot and you can try any board out you like.