Winter breeze after the rain, a play of colours throughout October

October seems to be a silent bridge of seasonal change. The wet scent of the monsoon still lingers in the air, white autumn clouds float in the sky; yet within the northern wind is the tune of winter's arrival. Sometimes the sharp sting of sunshine, sometimes sudden splashes of rain, and at other times the sight of the river's breast covered in morning mist — October is passing in the colours of diversity.

The Bangladesh Weather Observation Team (BWOT) says that although the first half of October will see sweltering heat and scattered rain, the southwest monsoon may leave the country by mid-October. And in the latter part of the month, the mood of the weather may change — if a new low pressure forms in the sea, rainfall may increase in the southern and central regions, and the sea may turn rough.

In the first 10 days of October, from October 1 to 10, the sky over the country will see a game of hide-and-seek between sun and clouds. The sky may remain partly cloudy for a large part of the day. In most areas of Chattogram division, along with greater cloud cover in the first two days, the amount and duration of rain may also be comparatively higher.

In Chattogram, Barishal, Dhaka, Sylhet and Mymensingh, there will be a greater tendency for short-lived scattered rain during this time. In other areas, the amount of rain is comparatively less. Most of the rain may occur between noon and 12am. Although there will be an average of 5 to 7 hours of sunshine during the day, sunshine may be somewhat less in Chattogram at the start.

However, amid the rain, there will be the discomfort of heat. Intense sweltering heat may be felt across the country. Normal drought conditions may prevail in Rajshahi and Rangpur. A mild heatwave may sweep through some areas of Rajshahi and Sylhet. Normal fog may be seen in the river basins of the central and northern regions in the morning. BWOT has advised caution as there is a risk of lightning along with rain.

Then October 11 to 20 — the second decade of October. During this time, the weather may remain fairly calm and clear. Although there may be somewhat more cloud movement in Khulna, Barishal, Sylhet and Chattogram, the possibility of rain will be low. In some places, light rain may occur between noon and night, with a greater tendency in the Chattogram region.

By October 14, the southwest monsoon may completely leave the entire country. After that, there will be no possibility of continuous rain. However, around October 19 and 20, the tendency for rain in the southern region may increase slightly. During this time, there is a possibility of 6 to 9 hours of sunshine during the day.

Another eye-catching aspect of this time is the Bay of Bengal. Between October 15 and 20, there is a slight possibility of a weak system or low pressure forming in the sea. Under its influence, the deep sea may become somewhat rough after October 17. If it rains, there will also be a risk of moderate to intense lightning.

But it is in the last 10 days of October that nature will change its form the most. Between October 21 and 25, the sky may become cloudy in the southern and central regions, increasing rainfall. A rain belt may become active. Sunshine hours may decrease — the sun's presence may drop to 4 to 8 hours a day. The deep sea may remain rough. There may also be a risk of landslides in hilly areas.

Then the scene will change again. After October 25, the sky may gradually clear and the possibility of rain may decrease. In the latter part, there is no possibility of sweltering heat or heatwave effects. Although normal drought conditions will remain in Rangpur and Rajshahi, morning fog in river basins will signal the next chapter of the season.

In other words, October will end not just with the departure of rain, but with the message of winter's arrival. Morning fog, northern wind and softening sunlight — all together, winter will begin knocking on nature's door at the end of the month. Between the departure of the monsoon and the arrival of winter, October thus becomes a strange, colour-changing month of weather.