Climate index explorer

Explore how the main modes of climate variability have evolved since the mid-1800s, from observations. Choose the indices, period and smoothing; hover over a chart, or use the arrow keys, to read values; and compare any two indices below.

Indices

Period

Smoothing

Positive phaseNegative phase

Show data table (annual means)

Compare two indices

Index A Index B Running mean

Lead / lag (months)

No lag

Correlation (r) –

Correlation at each lead and lag

Both indices are standardised over the period chosen above, so they share one axis. The running mean chosen here is applied to both before correlating. Inside the grey band a correlation is not significant at the 95% level, using an effective sample size that accounts for autocorrelation (Bretherton et al., 1999); running means leave only a handful of independent values.

About the data

Data last downloaded on . Values are monthly anomalies or index values as published by each source; running means are centred.