Mary Kilavi, Assistant Director Public Weather service, KMD said:
“There has been some sort of public outcry this season. Some people feel it is incredibly cold, and, as expected, we had already given out our forecast we expected the season to be cold as we know the June July, August season is usually colder than any other season within the country. The reason being that during this time of the year we get an incursion of cold air from the South (Southern Hemisphere) where we have winter at this particular time. When that happens, especially at the surface level, then it gets really cold. It gets a lot worse especially during the day when we have cloud cover that prevents the penetration of sun rays and mainly that happens when we have a layer of warm air at a higher level of the atmosphere or when we have some moist warm air that causes what we call inversion preventing sun rays from reaching the earth.”
Expert opinion on whether this season is colder than the previous years?
“People have been feeling this season has been extremely cold but when we look at the data, especially looking at the month of June, we realize it is true that some places have experienced slightly lower than average day time temperatures but these are just a few locations of the highlands East of Rift Valley that is including Nairobi and a few places of the South Eastern. In June, for example, Dagoretti’s maximum temperature was lower by -0.8 degrees than average, at Wilson Airport area it was also low by about by -0.6 degrees. Few other places that have recorded lower than average maximum detected day time temperatures according to our records are only Makindu by -0.3 degrees and Voi -0.4 degrees.
Most of the other stations have recorded average maximum temperatures for the month of June that’s for day time temperatures. We also see a similar trend when we examine minimum temperatures mainly night time temperatures. It is only a few locations that have recorded less than average for the month of June and these are places within the central highlands, like Embu and also South Eastern parts -Makindu, and just a few other places like Nyahururu, Kericho and Kisii. That is as far as June is concerned.
In July, the first few days have been much colder than usual during the day time temperatures. We have seen actually most of the stations recording less than average day time temperatures and it is only a few stations like Kakamega and Lamu out of many other stations that we have that have recorded slightly above average. So, we see that change between June and July, for the bit of July, that we have analyzed that we have seen a drop in day time temperatures. Night time temperatures are still slightly higher than average for most places except Embu and Makindu where we have seen minimum temperatures drop by about -2.7 and -1.5 degrees Celsius respectively. Elsewhere, we are actually seeing a decrease in above average minimum temperatures.
As far as this year is concerned, relative to past years, people have been saying it is the coldest they have experienced but analysis and comparison with some other years in the past shows otherwise. When we look at some of the places where the temperature has really dropped like in Nyahururu, temperatures sometimes go below 5 degrees Celsius.
Looking back over the years we realize that as far as maximum temperatures are concerned, we have had years that were much colder like for example 1988 was much colder in Nyahururu than it has been this year. I think that is the year when we had the lowest maximum day time temperatures and that was at about an average of 19.7 degrees Celsius in the month of June. This year has reduced to about 22.4 degree Celsius and many other locations actually experienced colder temperatures both maximum and minimum especially in the 80s. Contrary to what people actually think we have had years that were much colder than this year.”
Expert opinion on the high night temperatures and their possible impacts
“In line with the global trend we are actually seeing a rise in temperatures, especially at night that have been really consistent signaling a warming trend in all parts of the country. According to the projections that we have from climate change models, an increase in temperature is expected to lead to an increase in frequency and intensity of extreme events.
This means that we are going to see more extreme events like more frequent droughts and more intense in the future and also flooding due to heavy rainfall events. In other places like where they experience winter, more frequent winter storms and more extreme heat waves are to be expected. That is generally what the weather projections are showing. That is what is expected with a warming climate.”
Expert opinion on how weather patterns have changed
“As I had said, what is really consistent is the warming especially as manifest in the night time temperatures throughout the country and the trend is consistent over the years in line with the global trends. As far as rainfall is concerned the trends in rainfall are not quite significant but generally what we have been seeing is maybe a decrease in the long rains season and a lot of variability with the short rains. An increase in the intensity and frequency of droughts, for example, that is expected with a change in warming climate would then make a sector like agriculture a lot harder.”
Expert opinion on whether climate change has had any impact on the rainfall variability “Climate change is a very discernable trend where you can say that over the past 30 years we have seen an increase or a decrease in rainfall. Over and above that we have the normal variability expected during the year or inter-annual. For example, a certain year when we have had a lot of rainfall and maybe the following year a deficit in rainfall. When you examine that you will see that we have had ups and downs in as far as total amount of rainfall is concerned. But that does not necessarily translate into a trend, either a decreasing or an increasing trend.”