The dry spell has caused patches of brown grass to appear in places like Bishan Park.

Across Singapore, the signs and symptoms of a dry spell are clear: Parched grass, dry ground and low water levels in ponds and reservoirs.

A likely reason? A complex climate phenomenon known as the Indian Ocean Dipole (IOD).

The Meteorological Service Singapore (MSS) had warned earlier this month that the IOD is currently in its "positive" phase. This causes weather over South-east Asia to be hotter and drier than usual.

The impact of the positive phase of the IOD on South-east Asia is similar to the one that another climate phenomenon - El Nino - has on the region.

El Nino conditions have not been detected, but the positive phase of the IOD is likely to persist in the months ahead, said the MSS in its Aug 2 advisory. Each phase typically lasts about six months, with the negative phase bringing more rainfall here.

Last month, the total rainfall recorded at the climate station in Changi was 92 per cent below the long-term average, breaking the record set in 1997 for the driest July in Singapore, according to the weatherman.

Last month was also Singapore's second warmest July on record, with an average temperature of 29 deg C.

A spokesman for national water agency PUB said there has been a slight drop in the water level at Bedok Reservoir due to the warm weather.

"Generally, overall reservoir stock will drop during dry weather period," she said.

During dry months, PUB will top up Singapore's reservoirs with Newater, or recycled used water, to keep water reserves at a healthy level, the spokesman added.

"(This) will be further treated at the waterworks before supplying it to the population."

Details of water levels at Linggiu Reservoir, Singapore's main source of water in Malaysia, were not available.

Asked if the recent dry weather could be a symptom of climate change, Singapore Management University's Associate Professor of Humanities Winston Chow said it was too soon to tell.

Singapore has experienced dry spells before, he said, pointing to one that dragged on for almost a month from Feb 17 to March 15 in 2014.

He said: "Further studies after this event need to be done to establish if the dry weather is linked to climate change, or if it is within natural variability for tropical weather."