Little rain fell in twelve months
In the past 12 months, only February (165 mm) and March (53 mm) had adequate rain at Manilla. Rain was so scarce that the 12-month total was just under 500 mm, far below the average of 652 mm. So the drought situation has not improved lately.
Seasonal to annual shortages were not serious
Through the year, most rainfall totals for 12-months or less have been below the average, but not serious shortages. The acute phase of the drought was over by February, if not much earlier.
Two-year to eight-year shortages were extreme
This worst-ever drought for Manilla has been marked by extreme (often record-breaking) rainfall shortages with durations from two years to eight years. They persist in the data for August 2020 shown in this graph.
Twenty-year and thirty-year shortages
The shortages with the longest duration included here had been near the 70th percentile in 2012, but are now very much worse. The twenty-year (240-month) shortage is now in the 1st percentile.
How to read the graph
This graph shows all the present rainfall shortages at Manilla, short term and long term, as percentile values. The latest values are shown by a thick black line with large circles. Those from one month earlier are shown by a thinner line with small diamonds. [The method is described in “Further Explanation” below.]
Further Explanation
The following notes explain aspects of this work under these listed headings:
Data analysis
Cumulative rainfall totals
Percentile values
Severity of rainfall shortages
Limitations of this analysis
Monthly rainfalls form a single population
Observations are not retrospective
The rain gauge failed
climate by surly 