Yuanyang Rice Terrace in March

Should still be flooded, maybe some of the lower terraces will start to have green shoots peeking through, but very photogenic. Three days in the area is fine though more than you need if the weather cooperates. It's good to have some "backup" time in case there's fog on any particular day, which can wreck terrace viewing. There are villages to explore and when you arrive, you can find out which one(s) are hosting the rotating area market day. If you accomplish what you want to see in the first 2 days, then I highly recommend spending a day in and around the town of Jianshui (between Yuanyang and Kunming).

jiejie is right, it should be flooded although they may have planted some of the pools. Should be very nice.

How much time really depends how many sunsets/sunrises you want to view at different locations, and how much hiking you want to do between villages on the slopes. 3 days could be a good amount of time; but if you arent mobile and just want to hire a car to see all the sites it would be too long. On the other hand if you want to hit every vista at sunrise/set it wouldnt be enough.
The town of Xinjie has a nice market and I found it interesting. A chinese town perched up on top of the mountains. You could probably spend at least a half day just exploring it.

The town of Nansha is larger, with better transit connections but was not interesting.

I would make time for Jianshui, and some of the villages around it even if you do spend 3 full days in Yuanyang.

It's a nice area 3 days should be fine. As others have said, you can include Jianshui on the way from Kunming.

Some tips, you might not be able to get money in the terrace area. When I was there some time ago the banks were rural cooperatives that refused foreign cards, so bring some cash.

Depending on where you go after, there is a modern direct daily bus that is little known from Nansha to Hekuo or Nansha to Jinghong.

If you like the terraces you won't get bored in 3 days, there is a lot to see. Several years ago I spent 5 nights at the Photographer's Hostel in the middle of nowhere. I think I booked it on ctrip. The owner waited at the busstation and brought me by car to the hostel. His wife or girlfriend cooked nice dishes. From there every day I started in the morning, went out to the road in front of the hostel, flagged down a minibus or bus and visited all the different sites. There were no general entrance fees those days, but the terraces are worth an entrance fee. At some places I had to buy a ticket, at some not.

Wow! I'm getting more and more exciting about visiting the Yuanyang Rice Terrace. I'm glad that they'll still be flooded since I cannot travel in another time.

Jianshui is included on my travel plans. I expect to take a early bus from Yuanyang (Xinjie) and the continue to Dali on a night train.

I want to watch as much sunrises and sunsets as posible and I want to hike through the villages during the day.

Thank you guys for your comments. It has been very helpful.

By the way, does anybody know about public transportation between small villages? Can I just arrange private transportation to go to the viewpoints, go hiking around and being able to go back to Xinjie by minibús?

By the way, does anybody know about public transportation between small villages? Can I just arrange private transportation to go to the viewpoints, go hiking around and being able to go back to Xinjie by minibús?

There is no public transportation around the villages. You can pay for a seat in a sharevan to be let off along the way they are going or hire a taxi/sharevan to go where you like.

My hand-made maps(Fliker photos)---a bit old=2013

①Map of Yuanyang terraced fields and distances (Xinjie town=0 km)
https://www.flickr.com/photos/93515541@N04/34847724640/in/dateposted-public/

②Map of Xinjie town and accommodations
https://www.flickr.com/photos/93515541@N04/35069012412/in/dateposted-public/

3 days is needed for visiting Yuanyang terraced fields because Yuanyang is not the place to hurry and quickly move like other destinations.

Ii visited Yuanyang terraced fields 4 times before, and my 3rd visit, i stayed at Duoyishu village and Xinjie town for 15 days waiting for my friend coming from northern Yunnan and visited many places(all the places in map ① below) every day(didn't go anywhere on rainy days) but i wasn't bored so 3 days is too short to me)
---------------------------
(i.e.) 3 days
One day for---visiting "Duoyishu"（多依树） and "Bada"（坝达） terraced fields
https://www.google.co.jp/search?q=Duoyishu&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjq8I3m2bbUAhVLu7wKHUHDDZMQsAQIKw&biw=1280&bih=854 ---Duoyishu

One day for---visiting "Laohuzui"(老虎嘴）terraced fields(if you have enough time remaining after visiting Laohuzui, visit Laomeng（老勐）Market(slightly far and opened on Sunday--avalable by shared minibus or big bus coming from Xinjie etc)
https://www.google.co.jp/search?q=Laohuzui&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjw8Ky-2bbUAhUTO7wKHa_8BaEQsAQIOA&biw=1280&bih=854　 ---Laohuzui

One day for hiking + seeing terraced fields ---Xinjie→Jinzhuzhai(金竹寨)→Longshuba(龙树坝)→Xinjie(3.5～4 hours)
https://www.google.co.jp/search?q=Longshuba&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjv-rX327bUAhWJE7wKHYCwDxUQsAQIJQ&biw=1280&bih=854 ----Longshuba, famous for red colored rice terraces(with red algae)　

If it will be rainy day(not strong rain), you can enjoy walking among terraced fields with long rubber boots and a rain coat or umbrella but it's better with guide(ask it to your guest house owner) because terraced fields are very wide(missing your way!).