As the global weather phenomenon known as El Niño comes to an end and is forecast to be replaced by its opposite La Niña later this year, it is worth looking at examples of what the former has wrought and what the latter may have in store.

Most meteorologists agree El Niño, the warming of Pacific Ocean currents that impact weather patterns globally, will come to an end in the next couple of months. It was considered one of the strongest El Niños in history and had considerable impact on global weather patterns and crop production.

Such major grain and oilseed crops as wheat, corn and soybeans grown in temperate climates tended to do well during El Niño, resulting in record-large global wheat supplies and rising corn, soybean and soybean oil stocks. El Niño brought adequate if not ample moisture to most major growing areas in the midsection of the United States last year.

Crops grown in less temperate regions such as palm oil and sugar cane tended to not fare as well. Palm oil production in the current year in Southeast Asia is forecast to drop by more than 5%, with top-producing Indonesia expecting its first decline since 1998 and No. 2 Malaysia its sharpest drop since that year. Bursa Malaysia palm oil futures recently hit two-year highs. Price gains, though, are expected to be limited as users switch to other vegetable oils, including soybean oil, global supplies of which are forecast by the U.S. Department of Agriculture to be record high this year, due in part to strong soybean production aided by El Niño.

As the global weather phenomenon known as El Niño comes to an end and is forecast to be replaced by its opposite La Niña later this year, it is worth looking at examples of what the former has wrought and what the latter may have in store.

Sugar cane production in major growing countries like Thailand and India and importing countries like China also was sharply reduced from 2014-15, bringing to an end five years of global sugar surplus and contributing to price gains of about 50% from August 2015 lows in New York world raw sugar futures.

El Niño also brought much needed snow and rain to northern California and the rest of the U.S. Pacific Northwest, replenishing critical irrigation water. While parts of California to the south are in a fifth year of drought, too much of a good thing was bad for California’s prune-type plum crop as strong storms during pollination caused heavier-than-normal shed of developing fruit in early April.

Some private forecasts put the crop down 50% and as much as 80% from 2015, according to a Capital Press article. Production last year was 100,000 tons, dry weight. It was noted that the record-breaking El Niño of 1997-98 reduced the California prune crop by 40% from initial estimates of 170,000 tons to 102,000 tons.

Meanwhile, El Niño-induced wet weather also negatively affected the plum-type prune crop in Chile, tightening global supplies. California and Chile account for 80% of the world’s prune crop.

La Niña — the cooling of currents to below normal levels in the central Pacific Ocean — tends to have the opposite impact on weather patterns than does El Niño. La Niña is expected by most meteorologists to develop over the next few months with greatest impact in the Northern Hemisphere during the fall and winter. La Niña typically lasts 10 to 12 months.

Globally, La Niña is forecast to produce a stronger-than-normal monsoon for India, resulting in a turn-around in sugar production in the world’s second largest sugar producer. But it is expected to have minimal impact in Brazil, the world’s largest sugar producer.

In the United States and Canada, though, La Niña is a concern. La Niña may bring colder weather and more frequent storms, including average to above average snowfall, across the northern United States, which may impact winter rail transportation, wetter weather to the Pacific Northwest, drier weather to California and dry and mild weather to the South from Texas to the Atlantic coast, according to public and private meteorologists.

“A strong La Niña can be devastating for California … leading to more drought conditions,” AccuWeather said recently.

A strong La Niña also may prompt more tropical storms in the Atlantic Ocean, especially later in the hurricane season, which would be of special concern to Southeast sugar cane refiners and the Florida citrus industry.

La Niña has the potential to bring warm, dry conditions as the year progresses to the same parts of the United States that benefited from El Niño-induced moisture, with summer heat centered over the Northern Plains to the Great Lakes. Grain and oilseed traders, already surprised in late March by the U.S.D.A.’s unexpected 6% boost in forecast planted area for corn, are debating how much of a weather premium is needed in the market.

An example to weather’s effects on the markets came the week of April 18 when corn and soybean futures soared to multi-month highs as excessive rain significantly slowed Argentina’s soybean harvest and dryness raised concerns about Brazil’s second corn crop. But markets turned sharply lower on April 22 on profit taking and on ideas the run-up may have been overdone.

While meteorologists note that other factors also may contribute to weather events, La Niña will undoubtedly add to market volatility as the growing season progresses.