Here's what I THINK I know about typhoons:
- They can only happen in Summer and Winter...NEVER in Spring or Fall.
- Crops can be protected by increasing the HP and the defense stats. The items that do this are wettable powder, which raises defense, and tilling in withered grass, corn or four-leaf clovers, which raises HP to keep the crops from withering by hitting 0HP .
- Greenifier does not help in typhoons, as it only increases the quality of the soil, which governs how fast the crops in it gain levels, but does not contribute to defense or health.
- You can also protect crops from typhoons by giving the farm dragon they are on Gaia crystals, which will increase crop HP AND defense. Crystals can be purchased outright without needing to hunt for shards if you have enough money and have renovated the Crystalabra once through Palmo's shop.
- How often can they happen? Is there a minimum number of days between them?
- Is it possible to protect the crops 100% if you max out both defense and health? (I think the answer to this is 'no', that the storm can deposit a rock/etc on top of a crop randomly and completely destroy it.)
- Will villagers always warn you about an approaching typhoon at least two days in advance?
- Can you save/reload to avoid one? (Pretty sure you can't avoid your first typhoon of the game, but what about any after that?)