Future of Four Seasons in Maine and the Maine Data Literacy Project
How do El Niño and La Niña affect temperatures in northern New England?
Background: Have you ever heard of El Niño and La Niña? They are opposite ends of a
cycle of varying temperatures in the Pacific Ocean. El Niño is characterized by warmer
than average ocean temperatures and La Niña is characterized by colder than average
ocean temperatures. This phenomena affects weather patterns throughout the world,
even as far away as Maine.
The box plots below show the distributions for average winter temperatures for the X
years from 1950 to 2014 under three different conditions: El Niño (warm Pacific Ocean),
La Niña (cold Pacific Ocean), and Neutral (average Pacific Ocean temperatures). The
winter average is the average temperature for the three months of January, February,
and March for that year.
Data Source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ENSO/box_whiskers/
1. Describe what the graph shows about the distribution of wintertime
temperatures in northern New England (January, February, and March) in El Niño,
La Niña, and Neutral years.
(Purpose here is to elicit description of what the graph shows. Sample response: The graph shows that
El Niño years are associated with slightly warmer winter temperatures in northern New England than
La Niña and Neutral years. It also shows that even though the median winter temperature for La Niña
years is only a little more than 1°F cooler the median for El Nino years, temperatures are less variable
in La Nina years, with a narrower inter-quartile range and a smaller range of average winter
temperatures overall.
2. I interpret the graph to mean….
(Purpose here is to elicit an explanation (e.g. of the pattern or variability) or interpretation of the
meaning in terms of the context of the question. Sample response: In winter (January, February, and
March), in northern New England you can expect slightly higher temperatures in El Niño years than in
Neutral years, and in La Niña years you can expect similar temperatures to Neutral years but with less
variability.)
Bonus. Under which condition would it be easiest to predict the temperature?