Can I only buy it in season?
It is listed as Nakhon Nayok harvest listed Jan–Mar. The harvest period can vary by growing region and variety. The calendar does not guarantee that it is on sale on any given day.
Mayongchid / Marian Plum · มะยงชิด
If you see a small, yellowish fruit that looks like a little mango in Thailand, ask whether it is mayongchid. It is a fruit of the plum mango group, and mayongchid of Nakhon Nayok is introduced as a regional GI fruit. If you want to try a fruit different from a big mango, look for it in winter and early spring.
Nakhon Nayok harvest listed Jan–Mar
Harvest listed for a regional fruit
Use the main harvest period, or the harvest window for a regional fruit, as a guide. Actual availability can change with growing region, variety and weather.
Nakhon Nayok mayongchid is introduced as having both sweetness and tartness and crunchy flesh. Remove the seed in the middle and eat.
The Tourism Authority of Thailand introduces mayongchid of Nakhon Nayok as a regional GI fruit. You can learn about a small fruit that looks like a mango together with its growing region.
It is listed as Nakhon Nayok harvest listed Jan–Mar. The harvest period can vary by growing region and variety. The calendar does not guarantee that it is on sale on any given day.
Even among similar plum mango fruit, the variety and the name differ. Say you are looking for mayongchid, and it helps to get the actual variety and price from the seller.
If you want to read more about the food and the regions behind it, these sources are a good place to start. Ingredients and recipes can vary from one restaurant to the next.