El Niño affects the
weather in large parts of the world. The effects depend
strongly on the location and the season. We have studied the
CRU TS 3.22 analyses of 2-meter
temperature over land. As a measure of the strength of the
relationship we used the correlation coefficient with the
Niño3.4 index. The square of this number gives the
fraction of the variance that is explained by this aspect
of El Niño.
In the temperature maps, red colours denote locations that on
average are warmer during El Niño and cooler during La
Niña. Blue colours are colder during El Niño and/or
warmer during La Niña. Some North America effects are
non-linear: the effect of La Niña is not the opposite of the
effect of El Niño.