Monthly and Seasonal Variation of Cloud Cover, Humidity and Rainfall in Lagos, Nigeria

Abstract

The study of atmospheric variables such as cloud cover, humidity, and rainfall is needed to forecast/predict the weather to enhance policies implemented by the government concerning agriculture, water resources, and other relevant industries in Lagos State (6.45°N, 3.39°E), Southwest Nigeria. There is a need to ascertain the variability in cloud cover with other meteorological parameters in Lagos State which is fastgrowing with a total land mass of 1,171.28 square kilometers. Eleven years (2011-2021) ground data obtained from Visual Crossing a leading provider of weather data were analyzed on a monthly and seasonal basis using statistical tools. The results show that there is a significant rise in the extent of cloud cover in Lagos during July to September, with September being the peak month due to about sixty-three percent (63%) of the sky being cloudy in September. However, there is the minimum amount of cloud cover observed between December and February, with January being the least month about forty-one percent (41%) of the sky cloud-covered in the average year. Lagos experiences a yearly average humidity of 83.5% from June to October, peaks in September (87.88%), while the lowest value (77.26%) occurs in January. The annual average rainfall accumulation for the eleven (11) years is recorded to be 1611.30 mm. In June, September, and October, the rainfall rate is recorded to be very high with values that range between 242.53 mm, 227.25 mm, and 233.86 mm respectively, while December and January is observed to record the lowest accumulation of rainfall with values that ranges between 27.26 mm & 27.97 mm respectively. Finally, the comparison of the linear regression trend and the estimated Pearson correlation coefficient reveals a substantial, positive relationship exists between cloud cover and humidity, although cloud cover has a minor influence on rainfall. According to the study’s findings, it is advised that rainfall awareness programs be expanded and that government policies relating to agriculture, water resources, and other relevant sectors take into account the rising nature of rainfall in recent years.