Singapore sees wettest August on record by a large margin: country-wide average of 426.2 mm beating 293.6 mm
Singapore has seen the wettest August on record by large margin by country-wide average rainfall with some 426.2 mm beating the previous record of 293.6 mm in August 1996 (which also had negative Indian Ocean Dipole).
This is a country-wide average across several climate stations, so the statistical power of the record is much higher than for a single station. Country-wide average rainfall records date back to 1980.
In fact, August is part of the dry season, however, this August rainfall has beaten the average for the average wettest month, December which has an average of 331.9 mm of rain. The August average is only 146.9 mm.
The wet August was due to a negative Indian Ocean Dipole (IOD) combined with a wet phase of the Madden-Julian Oscillation (MJO) and low level wind convergence of winds over the region, according to Meteorological Services Singapore (MSS).
This shows how even in the absence of ENSO, the IOD can have a large influence on rainfall in the region, ENSO was neutral this August, Singapore's driest August on record was August 2019 which had the monster positive IOD but also neutral ENSO.
ENSO has often been blamed on the region's rainfall woes such as floods, drought and haze, but how much of the effect is really due to ENSO? ENSO is correlated with the IOD so a pure correlation between ENSO and rainfall would overestimate the causal effect of ENSO on rainfall.
Singapore August 2021 rainfall anomaly map:
This is a country-wide average across several climate stations, so the statistical power of the record is much higher than for a single station. Country-wide average rainfall records date back to 1980.
In fact, August is part of the dry season, however, this August rainfall has beaten the average for the average wettest month, December which has an average of 331.9 mm of rain. The August average is only 146.9 mm.
The wet August was due to a negative Indian Ocean Dipole (IOD) combined with a wet phase of the Madden-Julian Oscillation (MJO) and low level wind convergence of winds over the region, according to Meteorological Services Singapore (MSS).
This shows how even in the absence of ENSO, the IOD can have a large influence on rainfall in the region, ENSO was neutral this August, Singapore's driest August on record was August 2019 which had the monster positive IOD but also neutral ENSO.
ENSO has often been blamed on the region's rainfall woes such as floods, drought and haze, but how much of the effect is really due to ENSO? ENSO is correlated with the IOD so a pure correlation between ENSO and rainfall would overestimate the causal effect of ENSO on rainfall.
Singapore August 2021 rainfall anomaly map: