Interannual Climate Variability Tips

Climate Trivia: El Niño Frequency

Much of our weather in the United States depends on what is happening in the tropical Pacific Ocean. During an El Niño event, which is happening now, the eastern tropical Pacific is warmer than average. During La Niña events, the eastern tropical Pacific is cooler than average. While South America’s west coast may seem far [...]

Read More

Climate Trivia: El Niño Events and Frost Days – Great Basin

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Read More

Climate Trivia: El Niño and Frost Events – Pacific Northwest

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Read More

Climate Trivia: El Niño and Frost Events – Eastern U.S.

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Read More

Climate Trivia: El Niño and Frost Events – Southern U.S.

Winter is ending and the growing or “frost free” season is almost here! The frost free season is defined as the continuous period of the year when the temperature does not drop below freezing. When this season starts and how long it lasts have important implications for the plants and animals that live around us, [...]

Read More

Climate Number: 510 Years

Better understanding how fluctuations in climate have affected regional wildfire frequency over the past few centuries may help to improve our ability to predict severe wildfire seasons. Some of the West’s older groves have experienced dozens of wildfires over the past few centuries. The trees that survived these fires recorded black scars in their annual [...]

Read More

Climate Fact: North American and Eurasian Snow

Snow is both a product of the weather and a weather maker. It has long been recognized that snow exhibits a cooling effect on local and regional scales. Snow reflects more sunlight than bare ground, meaning that it absorbs less energy. More snow cover also means soils stay moist for longer following the spring melting [...]

Read More

Climate Number: Two Watts per Square Meter

The amount of solar energy Earth receives varies according to the “11-year solar cycle,” which corresponds to a cycle in the frequency and distribution of sunspots on the sun’s surface. The difference in solar energy between high and low points of the solar cycle is about two watts per square meter. About 35 percent of [...]

Read More

Climate Fact: Lake Warming in California and Nevada

Air temperatures are fickle – they fluctuate significantly from day to day, from season to season and from year to year. The temperature of a water body fluctuates as well, but is much more constant than the surrounding air temperature. Water has a higher heat capacity than air, which means it takes far more energy [...]

Read More

Climate Fact: Arctic Temperature Trend Amplification and the AMO

Temperature records suggest that the Earth’s surface temperatures warmed during the early part of the 20th century, cooled from the period 1940-1970 and have since been warming. While Arctic temperature trends have corresponded to this general warming and cooling pattern, it has followed these trends more severely. During the warming period from 1910-1940, the Arctic [...]

Read More

Climate Fact: The Ozone Hole and Climate

Near the center of Antarctica in the polar vortex, strong westerly winds that blow in a circle around the continent during winter trap an envelope of air near the South Pole, prohibiting this air from mixing with warmer air masses closer to the equator. The extreme cold in the vortex causes clouds to form in [...]

Read More

Climate Trivia: East Coast Winter Storm Frequency and ENSO

December is East Coast Winter Storm (ECWS) season. These storms are powered by warm water that flows from the Gulf Stream. The Gulf Stream current flows along the Eastern Seaboard past Florida and the Carolinas before reaching Cape Hatteras, where the warm water heads out into the Atlantic. ECWS’s travel northward along the coast causing [...]

Read More

Climate Trivia: ENSO and Regional Rainfall (Northwest)

Winter storm season is here. Storms will be blowing in from the Pacific, bringing rainfall to lower elevations and snow to the mountains. This year, the eastern tropical Pacific is in an El Niño phase, meaning that its waters are warmer than average. When the eastern Pacific is in an El Niño phase, the northwestern [...]

Read More

Climate Fact: ENSO and Regional Rainfall (South)

Winter storm season is here. Storms will be blowing in from the Pacific, bringing rainfall to lower elevations and snow to the mountains. This year, the eastern tropical Pacific is in an El Niño phase, meaning that its waters are warmer than average. When the eastern Pacific is in an El Niño phase, the southern [...]

Read More

Climate Trivia: ENSO and Regional Rainfall (Southwest)

Winter storm season is here. Storms will be blowing in from the Pacific, bringing rainfall to lower elevations and snow to the mountains. This year, the eastern tropical Pacific is in an El Niño phase, meaning that its waters are warmer than normal. When the eastern Pacific is in an El Niño phase, the southwest [...]

Read More

Climate Fact: Atlantic and Pacific Niños

It has long been known that what happens in the tropical Pacific doesn’t just stay in the tropical Pacific. Much of the year-to-year variability in America’s weather, particularly winter weather, can be explained by conditions there. All other things being equal, warm El Niño conditions off the coast of equatorial South America mean a wetter [...]

Read More

Climate Fact: Southern U.S. Drought Occurrence Linked to SST Variability: Causes of Northern Droughts Less Clear

Better drought prediction systems could potentially save billions of dollars. Current prediction systems largely rely on observations of the circumstances surrounding past droughts to understand the factors that led to drying. New research reveals that:
•    Drought in the southern Great Plains states, such as the 1946-1956 drought, can be largely explained by persistently cool [...]

Read More

Climate Fact: North Atlantic Sea Level Cycles

Global sea level is rising at a rate of about 1.2 inches per decade due to an influx of glacial melt water and thermal expansion of the oceans. The relative sea level rise that each coastal location experiences, however, differs from this global average due to local factors such as land subsidence and land uplift [...]

Read More

Climate Fact: Holocene ENSO Variability

Variations in the temperature distribution gradient in the tropical Pacific (characterized by the state of the El Niño-Southern Oscillation (ENSO), the oscillation in the eastern tropical Pacific between cool (La Niña) and warm (El Niño) states) exerts a strong influence on upper-atmospheric circulation and affects weather throughout the world. Surface temperature distributions in the tropical [...]

Read More

Climate Fact: Climate and North Atlantic Hurricanes

The torrential rainfall and storm surges associated with hurricane landfall events can cause what are known as “overwash deposits” that leave definitive marks in the sediment layers that accumulate in coastal areas. Analyses of sediment cores from various locations along the Eastern Seaboard and Puerto Rico show that for the last 1500 years, Atlantic Hurricanes [...]

Read More