3-year trends to September 2019

September extreme and arid

3-year climate trends to September 2019

September raw anomaly data (orange)


Daily maximum temperature anomaly (all x-axes): near the maximum for smoothed values.
Daily minimum temperature anomaly (lower left): has rapidly fallen very low.
Subsoil temperature anomaly (lower right): near normal again.

Moistures (moist is at the bottom)

Rainfall anomaly (upper left): extremely low.
Cloudiness anomaly (upper right): normal.
Dew point anomaly (middle left): now very low (arid).
Daily temperature range anomaly (middle right): extremely high.

 Latest fully smoothed data (red), for March 2019

Latest smoothed anomaly values (March 2019) all show a retreat from the extreme drought values of the summer of 2018-19.


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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