Can I only buy it in season?
It is listed as Nakhon Nayok harvest listed January–March. The harvest period can differ by growing area and variety. The calendar does not guarantee that the fruit is on sale on any given day.
Mayongchid / Marian Plum · มะยงชิด
If you see a yellowish fruit that looks like a small mango in Thailand, ask whether it is mayongchid. It is a fruit of the plum mango family, and Nakhon Nayok's mayongchid is introduced as a regional GI fruit. If you want to try a fruit different from large mangoes, look for it in winter and early spring.
Nakhon Nayok harvest listed January–March
Harvest period of a regional fruit is listed
Use the main season, or the harvest period of a regional fruit, as a guide. Actual harvests can vary with the growing area, the variety and the weather.
Nakhon Nayok mayongchid is introduced as having a mix of sweetness and sourness and crunchy flesh. Take out the seed in the middle and eat the flesh.
The Tourism Authority of Thailand introduces Nakhon Nayok's mayongchid as a regional GI fruit. It lets you learn about a small fruit that looks similar to a mango, together with its growing area.
It is listed as Nakhon Nayok harvest listed January–March. The harvest period can differ by growing area and variety. The calendar does not guarantee that the fruit is on sale on any given day.
Even within the similar plum mango family, varieties and names differ. It helps to say you are looking for mayongchid and to be told the actual variety and the price.
If you want to read more about the food and the regions behind it, these sources are a good next step. Ingredients and cooking methods can differ from one place to the next.