LAS VEGAS (KLAS) — The Las Vegas Valley just had one of the wettest and coolest winters in many years. It’s the opposite of what normally happens during a La Niña weather cycle. But according to the National Weather Service, this can happen when transitioning to an El Niño.
Typically a La Niña cycle brings cooler and drier weather to southern Nevada and El Niño brings hotter and wetter weather. The El Niño watch put out Thursday by the National Oceanic and Atmospheric Administration’s Climate Prediction Center point to the likelihood of another wet winter ahead.
The recent La Niña cycle lasted at least two years, according to Las Vegas NWS Meteorologist Brian Planz. He added that currently, the area is in what is called a neutral pattern — in between La Niña and El Niño.
What all of this means for the weather in Las Vegas is a toss-up right now. After all, the Mojave Desert can expect extreme heat at some point over the next several months, but whether extended periods of hotter or cooler air will move into the valley is not yet known.
An El Niño pattern could also push back the traditional monsoon season for the valley.
In a paper published by the National Weather Service (see below) written in part by local NWS Meteorologist Stan Czyzyk about 10 years ago, he wrote that between 1951 and 2008, “El Niño episodes were wetter than average in 10 of the 18 July-June seasons – or 56% of the seasons studied. However, when just cold season precipitation for the November through April period is looked at 13 of the 18 seasons or 72% of the episodes were wetter than average.”
Historic El Niño precipitation and snowfall in the Las Vegas valley
| El Niño episode | Strength of Episode | Las Vegas July-June Precipitation Total | Las Vegas July-June Seasonal Snowfall Total | Las Vegas November- April Precipitation Total | Las Vegas December- February Precipitation Total |
| 1951-1952 | Weak | 5.58” | T | 3.81” | 1.30” |
| 1957-1958 | Moderate | 6.29” | T | 2.62” | 1.17” |
| 1963-1964 | Weak | 3.14” | T | 0.45” | 0.07” |
| 1965-1966 | Moderate | 4.15” | T | 3.34” | 1.07” |
| 1968-1969 | Weak | 4.54” | T | 3.19” | 2.60” |
| 1969-1970 | Weak | 2.17” | T | 1.25” | 0.87” |
| 1972-1973 | Strong | 8.43” | 0.7” | 5.59” | 2.32” |
| 1976-1977 | Weak | 5.06” | 0.0” | 0.55” | 0.24” |
| 1977-1978 | Weak | 7.24” | 0.0” | 5.07” | 3.57” |
| 1982-1983 | Strong | 4.45” | 0.0” | 3.42” | 1.47” |
| 1986-1987 | Moderate | 4.84” | 0.6” | 3.52” | 2.05” |
| 1987-1988 | Moderate | 5.03” | T | 4.36” | 1.80” |
| 1991-1992 | Moderate | 8.77” | 0.0” | 7.19” | 1.99” |
| 1994-1995 | Moderate | 5.53” | T | 4.81” | 4.11” |
| 1997-1998 | Strong | 7.68” | 0.0” | 4.53” | 3.13” |
| 2002-2003 | Moderate | 4.20” | 0.0” | 3.04” | 2.22” |
| 2004-2005 | Weak | 10.26” | 0.0” | 8.86” | 6.62” |
| 2006-2007 | Weak | 1.66” | T | 0.42” | 0.34” |
| 30 Year Normal | N/A | 4.49” | 1.0” | 2.73” | 1.68” |
| 18 Events | All Strengths | 5.49” | T | 3.67” | 2.05” |
| Average for Moderate and Strong Events | N/A | 5.94” | T | 4.24” | 2.13” |
Their Impact On The Weather In
The Las Vegas Valley” weather.gov
Historic El Niño precipitation and snowfall in the Las Vegas valley
| Episode | Strength of Episode | Las Vegas Average Temperature Compared to 30 Year Normal | Las Vegas Average Temperature Compared to Rolling ~30 Year Normal |
| 1951-1952 | Weak | 44.2 | 44.2 |
| 1957-1958 | Moderate | 48.3 | 48.3 |
| 1941-1970 Normal: 46.2 | |||
| 1963-1964 | Weak | 44.1 | 44.1 |
| 1965-1966 | Moderate | 44.5 | 44.5 |
| 1968-1969 | Weak | 44.9 | 44.9 |
| 1969-1970 | Weak | 47.4 | 47.4 |
| 1951-1980 Normal: 46.8 | |||
| 1972-1973 | Strong | 43.9 | 43.9 |
| 1976-1977 | Weak | 48.8 | 48.8 |
| 1977-1978 | Weak | 50.6 | 50.6 |
| 1961-1990 Normal: 47.1 | |||
| 1982-1983 | Strong | 47.6 | 47.6 |
| 1986-1987 | Moderate | 47.4 | 47.4 |
| 1987-1988 | Moderate | 46.7 | 46.7 |
| 1971-2000 Normal: 48.2 | |||
| 1991-1992 | Moderate | 49.0 | 49.0 |
| 1994-1995 | Moderate | 51.2 | 51.2 |
| 1997-1998 | Strong | 48.0 | 48.0 |
| 1981-2007 Normal: 48.7 | |||
| 2002-2003 | Moderate | 51.1 | 51.1 |
| 2004-2005 | Weak | 51.3 | 51.3 |
| 2006-2007 | Weak | 49.4 | 49.4 |
| 1991-2007 Normal: 49.4 | |||
| 1971-2000 30 Year Normal | N/A | 48.7 | N/A |
| Average for Moderate and Strong Events | N/A | 47.8 | N/A |
Their Impact On The Weather In
The Las Vegas Valley” weather.gov
Czyzyk concluded that in the Las Vegas Valley, both El Niño and La Niña changed the amount of precipitation the most. “El Niño episodes in Las Vegas tend to have normal to above normal precipitation for the period July-June as well as during the cold season months of November through April and to a lesser extent when just the December through February period was analyzed,” Czyzck and Stachelski wrote. “La Niña episodes tend to have normal to below normal precipitation during both the July-June season and in the cold season months from November through April. The chances for measurable snow, especially significant measurable snows in excess of 2 inches, is greater than normal during a La Niña episode and less likely than normal during an El Niño episode.”
Las Vegas Weather Planner
