On the average, Malaysia receives about 6 hours of sunshine per day. There are, however, seasonal and spatial variations in the amount of sunshine received. Alor Setar and Kota Bharu receive about 7 hours per day of sunshine while Kuching receives only 5 hours on the average. On the extreme, Kuching receives only an average of 3.7 hours per day in the month of January. On the other end of the scale, Alor Setar receives a maximum of 8.7 hours per day on the average in the same month.
Solar radiation is closely related to the sunshine duration.
Its seasonal and spatial variations are thus very much the same as in the case of sunshine. Evaporation Among all the factors affecting the rate of evaporation, cloudiness and temperature are two of the most important ones in this country. These two factors are however inter-related. A cloudy day will mean less sunshine and thus less solar radiation and in turn give rise to lower temperature. An examination of the evaporation data shows that the cloudy or rainy months are the months with lower evaporation rate while the dry months are the months with higher rate.