In the recently concluded month of April, rainfall across the country exceeded the seasonal average by more than 75 per cent, according to the long-range forecast issued by the Meteorological Department. The report also highlighted significant regional variations, with the Barisal Division recording the highest level of rainfall among the eight divisions. As a result of the increased precipitation, temperatures during the month remained lower than the climatological average.
April is typically considered the hottest month of the year in the country, with an average temperature of 33.2°C. However, during the past April, both maximum and mean temperatures remained below normal by 0.6°C and 0.1°C respectively. The highest temperature recorded during the month reached 40°C on only one day, while the lowest temperature was 16°C.
At the beginning of the current warm season, the Meteorological Department had forecast that April would not experience severe heat intensity. This forecast was largely reflected in observed conditions. On 22 April, only Rajshahi recorded a maximum temperature of 40°C. By comparison, April 2024 experienced continuous heatwave conditions throughout the month. In contrast, this year’s April saw intermittent heatwaves that did not persist for extended periods.
The month began with a brief spell of heatwave conditions, which subsided within two days. Rainfall commenced during the first week, followed by a return of heatwave conditions after the second week, lasting for around seven days. However, these conditions were not uniform across the country and were confined to a maximum of 22 districts. Rainfall returned again towards the end of the month.
Heatwave Classification
| Category | Temperature Range |
|---|---|
| Mild heatwave | 36.0°C – 37.9°C |
| Moderate heatwave | 38.0°C – 39.9°C |
| Severe heatwave | 40.0°C – 41.9°C |
| Extreme heatwave | Above 41.9°C |
Division-wise rainfall in April
| Division | Rainfall anomaly |
|---|---|
| Barisal | Over 169% above normal |
| Dhaka | Around 80% above normal |
| Rajshahi | Slightly below normal |
| Other divisions | Not specified |
The forecast for May suggests that rainfall is likely to remain near normal. The Meteorological Department indicates the possibility of one to two low-pressure systems forming during the month, with one potentially intensifying into a depression or cyclone. However, the likelihood of cyclone formation is considered low by departmental sources.
Additionally, between five and six episodes of nor’westers (locally known as Kalbaisakhi) are expected in May, with two to three days likely to experience severe thunderstorms. May is regarded as the second hottest month of the year. The forecast indicates the possibility of one to three spells of mild to moderate heatwaves, along with one severe heatwave event.
According to senior meteorologist Mohammad Bazlur Rashid, intermittent rainfall may continue until around 10 May, keeping temperatures relatively stable during this period. After 10 May, a gradual rise in temperature is expected. Heatwave conditions may develop after 15 May and could persist for approximately six to seven days. Overall, temperatures in May are expected to remain relatively tolerable.