September marks roughly the end of the harvest season and the start of a new growing season for coffee in central-south Brazil, the world’s No. 1 coffee-producing country at more than 30% of the output, according to the U.S. Department of Agriculture (USDA).

However, the key coffee-growing region of Minas Gerais in Brazil has not had significant rain in three months. Also, temperatures have been above normal in the state, which has stressed crops, according to one Brazilian analysis.

Minas Gerais and Espirito Santo, which are also experiencing higher-than-normal temperatures, combined generate roughly three-fourths of Brazil’s coffee production.

“It looks like it’s going to be a slow start to the rainy season in the coffee areas of Brazil and, of course, the markets get a little jittery,” said AccuWeather senior meteorologist Jason Nicholls.

According to an AccuWeather analysis, average temperatures have been a whopping 7 degrees Fahrenheit above normal, and average precipitation has been 57% below normal since June 1 in the municipality of Franca in Sao Paulo on the Minas Gerais border of Brazil.

“There’s no rain forecast for this week, next week or possibly the last week in September,” said Nicholls. “It could be early to mid-October, which is a little late, before that area gets at least a half of an inch of rain needed to have the coffee beans start to flower. If it’s not raining by mid-October, it’s really a problem.”

It’s still early, though, and no time for great concerns yet, Nicholls said.

“If the rains do arrive and it rains consistently in late September or early to mid-October,” he said, “then you’ll still have a fine crop. Rainfall is the biggest key to the growing season in Brazil.”