In just three days beginning Friday, Teknaf experienced 482 millimetres of rain, exceeding what is usual for the whole of August.
The Flood Forecasting and Warning Centre (FFWC) records Teknaf's maximum and normal rainfall for August at 1,382mm and 438mm, and the number of rainy days at 12 to 25.
The coastal upazila had 1,019.4mm rain on just a few days between August 1 and 17.
Similarly, Lorergarh of Sunamganj got 1,038mm rain in the 17 days and 267mm in three days till Monday. The area's maximum and normal rain for the month are 1,480mm and 880mm, according to FFWC.
In sharp contrast, farmers in many other parts of the country find cracks in their dried up Aman field.
The Ghagot and Teesta rivers are flowing above the danger level, eroding their banks and flooding villages in Gaibandha due to upstream storm water. But in many other villages of the district, water to rot jute plants has become scarce and this is a big concern for farmers.
Usually, July is the peak of the monsoon in Bangladesh, but there was 34 percent less rainfall last month following a dry spell.
Most of the downpour occurs in the country in June and July with 460mm and 523mm rain respectively on an average. Each month gets 12 to 24 rainy days, varying from region to region.
This year, the monsoon remained largely inactive throughout the two months, though the season started on June 15.
The monsoon became active from mid-August, causing substantial rainfall. Met officials, however, say there is nothing unusual about this rain pattern.
“If the Asian monsoon becomes active, rainy weather in Bangladesh can continue till mid-September,” said Hafizur Rahman, duty forecast officer of the Met office, last Friday.
But some experts link this pattern with climate variability and climate change.
“We are noticing this kind of climate variability repeatedly here, said Dr Atiq Rahman. “The present behaviour of the weather in Teknaf is not common and such behaviour is accentuating the extreme weather events.”
Article 1 of the UN Framework Convention on Climate Change defines "climate change" as: "a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods".
The UNFCCC thus makes a distinction between "climate change" attributable to human activities altering the atmospheric composition, and "climate variability" attributable to natural causes.
Another key difference between climate variability and change is in persistence of "anomalous" conditions, in other words, events that used to be rare occur more frequently, according to the World Meteorological Organisation website.
A never-seen-before event or sequence of events, such as the exceptional hurricane season in the Atlantic in 2005, could be part of natural climate variability.
If such a season does not recur within the next 30 years, 2005 will be considered an exceptional year. But its recurrence will suggest a potential change in climate.
UNEVEN RAIN DISTRIBUTION
From August 1 to 17, Naogaon got 56.5mm rain, Gaibandha 64mm and Dinajpur 99mm. Maximum and normal rain for these places are 690mm and 265mm, 528mm and 236mm, 891mm and 349mm respectively.
“I am yet to plant Aman saplings. It is already late. Farmers are facing difficulties in rotting jute plants because of the lack of water,” said Saidur Rahman of Khilkhet in Gaibandha Sadar upazila.
On the other hand, rains have disrupted life in the capital and in Chittagong city.
There has been huge rainfall in parts of India too. Some rivers were flowing above the danger level while a rising trend was recorded at 59 monitoring stations out of 81 on Sunday.
Prof Dr Ainun Nishat, a key member of the government's climate change negotiation team, said the unusual pattern of rain was an impact of climate change.
Lack of rain in the northern region means farmers would have to depend on groundwater for Aman cultivation, leading to a fall in the water table, he said.
“The situation will get worse in future and we need to take preparations for that.” The management of the flood protection embankment and drainage system in the capital has to be improved, he added.
If the authorities just keep providing some relief after flood and river erosion, and do nothing else, “it will be hard to face the situation.”