Summer rains and bad weather in europe in the early fourteen century resulted in

Famine

In the early 14th century, Europe encountered a series of famines, often referred to as the Great Famine. Abundant rains in the spring of 1315 were partly responsible, along with cool warmth. This did not enable the cereals to ripen, which led to crop failures. It also recommended that straw and hay could not be preserved for animals and that salt was not available because the ocean could not evaporate. Moreover, the population had expanded very suddenly prior to 1300, so there was an additional requirement on limited sources.