How does weather and climate affect farming and agriculture?

Weather affects crop quality, plant health, harvest, etc. If you do not have a greenhouse (it is a controlled environment in terms of temperature and precipitation (irrigation) protecting your plants from hail), you rely on weather conditions.

All examples provided here are from Northern Hemisphere (Turkey)

For example, for walnuts, some types of walnut trees wake up early in April, some others wake up late April (e.g. Fernor type). If you have freezing conditions in early April (let's say 10th of April), you loose your possible walnuts long before your harvest. Harvest time for walnuts in Turkey is September and October.

Extreme events (such as storms) cause problems even in greenhouses. They can be as strong as to fully demolish greenhouses. It occurred in Antalya (Turkey) 3 to 4 months ago.

There is always a risk in agriculture because you cannot control weather.

Similar to weather, climate has an important role in agriculture. There are some vegetables and fruits that belong to monsoon climate. You cannot have it in desert climate.