To prepare for the spring planting, Montana wheat farmers could ask Peruvian fishermen about their catches. Poor fishing in Peruvian waters result from the same El Niño conditions that cause a warm dry spring in Montana.

The warm waters of the El Niño and its cool-water sister, La Niña, affect weather patterns world wide. Joseph Caprio of Montana State University studied a century of weather records from Peru and Montana to determine how the El Niño Southern Oscillation, the collective term for El Niño and La Niña, affects both places.

"An increase or decrease of extreme daily weather occurrences can impact natural resources and a wide range of human activities including agriculture, forestry, recreation, construction and other businesses," said Caprio in a press release.

BLOG: Foggy Notions for a Thirsty World

Caprio looked at temperature and precipitation data from 50 normal years, 25 El Niño years and 25 La Niña years. He focused Montana temperature and precipitation data from the dates between Dec. 3 and June 23, and Peruvian sea surface temperatures from November through March.

He found that the El Niño Southern Oscillation and Montana weather had a statistically significant correlation.

La Niña conditions off the coast of Peru mean a fatter catch for the fisherman there and a cool wet spring in Montana. La Niña conditions this spring had just that effect, but left East Africa in a drought.

BLOG: East Africa Drought Linked to La Niña

La Niña ended recently, and normal conditions now prevail over the Pacific. The National Oceanic and Atmospheric Administration (NOAA) predicts that these normal conditions will persist through the fall.

NOAA doesn't forecast an El Niño anytime soon. But when El Niño is in effect it can mean 20 percent more days with extreme high daytime temperatures, 20 percent fewer days with extreme low nighttime temperatures and 20 percent fewer days with high precipitation amounts, Caprio reported.

Warmer springs allow farmers to plant earlier, but if hotter Montana summers follow, the crops may whither before they produce plump grains.

IMAGE: Round hay bales of alfalfa in a Montana field. (Wikimedia Commons)