Hello friends.
I have been living in Taiwan since 2015 now, so flew back home (France) only twice (both times for a month in December).
Two years ago I booked my flight in september that cost me about 800 Euros.
Last year I booked earlier, in July and found a cheap flight of 695 Euros.
I was checking the prices right now. I know it is early but I thought the earlier the better… and to my surprise, the same flight that I took last year in December cost 930 Euros, and this is the cheapest one.
How do you explain such a huge price difference? Should I wait for July then? Why would it not be cheaper to book very early, that makes no sense, or does it?
Or is it because there is less competition if you book too early so companies try to take advantage of that?
Any help appreciated 
edit: initial message not clear about the date, December, every year (never fly back in summer).
Could be supply and demand. Do any of the dates that you searched for intersect with a Taiwanese holiday?
2 things: 1) always summer time. Typically Taiwan airplane tickets go 20% higher around June 20 thereabouts for the summer season.
2) jet fuel prices highest point from end-2015 until now. see chart.
@nonredneck
Same as 2015 and 2016, no difference in date, I’ll go back home around 1st december more or less and come back around 30th december. But good question actually, prices differ whether you book on 28 or 31th, typically 31th might be cheaper since not many people want to celebrate (western) new year in a plane (I don’t mind it).
@CTaitung
Thanks for the tip. 20% is a big difference. I’ll see what I find a little later then.
Yep, 20% is big. It actually means that if you leave on (or around June 20), then the price of ticket after that date (on or around June 20) goes up like 20% for the next 2 months. Was in eztravel booking tickets and they basically told me the break-point for leaving Taiwan before prices go higher was around then. No reason explained.
Also, I believe last day of public school is like June 30, so all those Taiwanese kids who go abroad for the summer starting July 1 and later raise the demand as well.
You could also check the airline’s refund policy. Some of the Asian airlines have a cheap refund fee (like $1000 NTD or so). Check the cost of the refund fe before you purchase the ticket. If the fee is cheap, you could buy the ticket now and if the price drops by more than the refund fee, cancel your old ticket for a refund and buy a new one.
Though in my experience trying that, the price has never gone down enough.
Now I’m looking at flights in June and I have found round trip for 550 Euro. I’m not interested personally because it is a long trip on a Chinese Airline.
I’ve already flown Taipei to Paris twice this year. And going again in June. I usually fly EVA Air Lines because it is a direct flight and convenient.
Cathay is the cheapest non Chinese Airline for 806 Euro.
Kayak.com is great reference.
Yep tango42 Cathay is great, I think I flew with them two years ago, together with Turkish Airlines (the latter clearly deserves the award of best european company from my experience).