3-year trends to January 2019

January very hot

3-year trends to January 2019

January raw anomaly data (orange)

In January 2019, the daily maximum temperature (x-axes, all graphs) and daily minimum temperature (lower left graph) were extremely high, while the subsoil had warmed to normal. Rainfall was very low, while cloudiness, dew point and daily temperature range were near normal.

 Fully smoothed data (red)

By July 2018, the last date for which data can be fully smoothed (as described below), variables had already peaked, or were about to peak, in their contribution to an extreme drought.

More recent data, only partially smoothed, suggests that temperatures and rainfall have since returned towards drought.


January data points are marked by squares.


Smoothing uses Gaussian functions.
For fully smoothed data the function has a Standard Deviation of 2.5 months, it spans 13 monthly data points, and has a half-width of 6 months, which suppresses cycles shorter than 12 months. For partly smoothed data, the span of the function is reduced to 11 months, 9 months and so on.

Fully smoothed data points are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange.

Limiting values

Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

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