The harmattan experience in Nigeria

1. This is the northeast trade wind emanating from the Sahara, which blows across West Africa, and reaches Nigeria typically from November in a year and ends around March the following year. It therefore expectedly reaches Nigeria’s northern arid borders before the rainforest and mangroves of the south on the Atlantic Ocean.

• The harmattan in Nigeria is characterised by hazy conditions, often windy and dusty, and low temperature especially at night and in the mornings. Hitherto we experienced significant daily temperature fluctuations, sometimes from 9°C to 30°C. So far, as at the second week in January 2026, this has not happened.

• This has led to the very widely commented no harmattan in December 2025 and so far in January 2026, in Nigeria.

Questions arise

• As a result of the experience this December 2025/January 2026, people are asking questions. These include:
  • How do we explain this phenomenon/What could have caused this?
  • What should we expect this year?
  • What other impact could there be?

A brief on how we addressed these questions

• The simple way to go about this would be to look at meteorological records and see if we have had this experience in the past. We cannot rely on human memory because that is weak. The world of science and policy requires that we produce evidence. If we find a similar year in the past, we may then look into the year that followed and imagine what to expect.

• Being in the southeast of Nigeria, the closest research institute to me, having reliable meteorological records is the National Root Crops Research Institute (NRCRI) at Umudike, in Abia state. That institute has the longest records on such parameters. Available data at the NRCRI spanned 103 years, and included data on temperature, wind, and dust. Absence of harmattan in this period is indicated by higher-than-average temperature for period, less dust in the atmosphere, and less wind speed.

• In the past, may be up till the 1980s most primary and secondary schools in the same southeast Nigeria collated basic meteorological records and recorded them. These they did using simple rain gauges and wind vanes or weathercock. Today, I cannot find one school with rain gauge, wind vane or weathercock indicating the cardinal points of North, South, East and West, not to add thermometers recording day time and evening temperatures.

• Despite the multiplicity of policies, plans, strategies, and numerous “talkshops” and workshops, conferences etc. on climate change etc. we are in many practical ways technically behind and inferior to what we had pre- and immediate post-independence era, up till the 1980s, on this subject.

• The lack of data is a well-known limitation to addressing the challenge of climate change, and has limited the quality of our national plans, including the Nationally Determined Contributions (NDCs) submitted to the United Nations Framework Convention on Climate Change (UNFCCC), and indeed most aspects of planning at all levels of governance in Nigeria.

1. If the sub-nationals were serious entities in Nigeria and sincere on their claims on climate governance and climate change policies and plans, they should urgently be restoring the collation of climate and weather data in all schools, and I add, in all churches in the area. Churches, because there is hardly any community in the southeast without a church. Of course this could be applied across Nigeria.

1. This is important because science recognises the need for high density data collection as there is very strong variation in weather and climate parameters over small areas. Unfortunately, the NRCRI data collated at Umudike has over decades been used as proxy for the entire region.

What does records at NRCRI Umudike show?

1. From the records at the NRCRI Umudike, dating over a century, we can confirm that the phenomenon this year has never been experienced. According to researchers at the NRCRI, “based on 103 years digitise meteorological records from the Umudike microclimate zone, a complete absence of Harmattan has not been previously observed.”

1. In the past the harmattan has never failed to happen. What has happened are harmattan of varying intensities or severities. Some years may be mild and some years may be more intense. But never has it failed to happen: “From our 103 years meteorological records for rain, temperature, wind, and dust parameters, no year within our dataset indicates a complete absence of Harmattan conditions. Observed variations reflect intensity fluctuations rather than total disappearance.”

1. In effect from scientific records the total or complete absence of harmattan has never been recorded.

Question 1: How do we explain this phenomenon/What could have caused this?

1. We could start by reflecting on wat triggers the harmattan and why has that trigger not happened, or if the trigger is still in place and acted, why did the harmattan-effect not happen? This is a challenge for atmospheric scientists and researchers.

1. It could be simplistic to attribute this to climate change. It may be, it may also not be. If what we experience December 2025/January 2026 becomes irreversible, not temporary, that is if we do not see a restoration of previous conditions in this period of the year, then we could place that in the realm of climate change. If that is not the case, that is, we see in December 2026/January 2027 and beyond the return of the long-term weather characteristics of these same parts of the world, then we could define what we now see as mere variability. If, however, we insist on this as the impact of climate change then we could see this as an extreme weather occurrence.

The rain in late December 2025 in several locations in Southeast

1. A case of extreme weather event. As reported from multiple locations in the southeast of Nigeria, in late December 2025 we had a few days of rains of varying intensity. In my home at Umuezeala-Nsu in the Ehime-Mbano LGA of Imo State, the rain was unusually heavy. While I recorded that by video, there was no rain gauge to have data on this in terms of millimeters of rainfall. In the same community in the 1970s the primary schools had rain gauges and wind vanes. We therefore limit to the inadequate statement of “heavy” rain.

1. Rainfall in December are not totally unseen in the past, but this time it was heavier than usual.

1. On the rainfall of December 29, 2025, researchers at NRCRI reported on how widespread the rainfall experienced was and if it has happened before, and if it has, was that also in the years with no harmattan. If yes, what followed in the next year?

– Their response: Within the Umudike microclimate zone under our coverage, no rainfall was recorded in December 2025, indicating strong spatial variability. However, historical records (1921–2025) show rare on 29th Decembers. Records we have for rainfall events 29th December are as follows: in 1929 (6.04 mm), 1934 (9.31 mm), 1958 (0.47 mm), and 1990 (0.10mm).”

In effect while we at Umuezeala-Nsu, approximately 20kms Northwest of Umudike experienced such heavy rainfall, Umudike did not. Refer again to the earlier statement on the need to increase the density of collection of weather data.

• In the same locations around Umuezeala-Nsu in 2024, commencement of rainfall was delayed. Farmers had started operations only for the rain not to come when expected. Farmers lost. The same farmers expected delayed rains in 2025 and did not see the rains coming earlier. They delayed farming. Again, farmers lost.

Implications: Farmers do not like uncertainties. In rainfed cropping systems these adversely impact farmers. As these irregularities and swings have emerged as a new pattern, we can add a new impact of climate change as uncertainties in weather parameters.

• Before now, the commonest mentioned impacts of climate change in the literatures have been:
• Rising temperature;
• Changing precipitation/rainfall regimes (commencement and duration, volume and intensity); and,
• Increased frequencies of extreme weather events.
• When we merge the steady lack of pattern on commencement dates for rainfall and now the harmattan absence phenomenon, we can add a fourth impact of climate change as

–  Uncertainties on the direction of change on all parameters of weather and climate, simultaneously occurring. As a result, famers and other stakeholders cannot plan based on experiences as no weather parameter has a pattern any longer.

• Outstanding are of course investigations on the triggers of no harmattan beyond climate change. What is it that usually happened in the global climate and atmospheric systems, and specifically, what triggers the northeast trade winds from the Sahara that leads to harmattan in West Africa, that did not happen this year? This should interest researchers and atmospheric scientists. Are there significant changes to the Sahara ecologies? How much of vegetative cover is there. Can the Greening of the Sahara be a way forward, and can the governments of West Africa do to/with the Sahara what some other parts of the world have done in greening their deserts? This opens new research questions on whether changing the Sahara land cover may be influencing regional wind systems.

Question 2: What should we expect this year?

• Science is no voodoo, and we have to rely on what is known to model the future. However, since we have never had the absence of the harmattan, we do not stand on solid grounds to make statements on what we can expect this year. If we had such an experience in the past, we could easily fall back to referencing what followed the period of no harmattan.

• We can only present a sample of responses from a few researchers and farmers on what to expect. These fall into two broad categories – biophysical and economic:
• The commonest perception is that the harmattan prepares fruit trees for flowering and fruiting. Therefore, there is fear that in 2026 most fruit trees will perform less optimally. Reduced supply and increased cost may be coming.

• There is fear that farmlands are having less leaves shed by trees (reduced fertility, sans bush burning), and more shrubs still green. Therefore, farmers have more work to do on land preparation. Labour, which has been a major challenge in terms of availability and cost will pose more challenges this year. It will be good to encourage farmers to stop bush burning. Unfortunately, public and private extension services are weak in the area.
• Most farmers store cassava in the soil and harvest when needed. Cassava is a strategic food security crop in the area. With high soil temperatures farmers expect more rotten cassava tubers, and therefore less produce this year, and therefore higher costs of products from cassava produce.
• Yams stored in barns will be adversely affected by higher temperature. The speed of yams rotting will be faster, and therefore less arriving in good form in the market in the course of the year, and therefore higher cost.

Question 3: What are the impacts?

• On a positive note, we have seen less adverse health challenges unlike years with harmattan. These include respiratory issues like increased risk of colds, coughs, asthma, bronchitis, and pneumonia due to dust inhalation. We have seen less dry skin, cracked lips, and hair breakage. We also see less irritation of the eyes, as dust can cause red, itchy, watery eyes.

• We see less fires outbreaks, and cancellation of flights dues to reduced visibility.

Are there other relevant or related information on these?

• Several other unusual climatic features have recently been observed. Notably, the 2025 records show the longest August break since 1921. This underscores the increasing frequency of atypical weather patterns. The Agrometeorology Unit at the NRCRI Umudike maintains a fully digitised weather database spanning 1921–2025, which supports these observations. Data Source: Agrometeorology Unit National Root Crops Research Institute Umudike (NRCRI) (2026).

Responses from researchers at NRCRI on the December 2025/January 2026 Harmattan

1. The Harmattan season did not occur – are we still expecting it in view of climate change?

– “The Harmattan has not completely disappeared, but it has been delayed and weakened in many parts of Nigeria due to climate change. In places like Abia State and much of the southern region, the expected dry, dusty and cool conditions were replaced by warm and humid weather well into January. Some Harmattan influence is still being felt in parts of the country and may strengthen slightly, but it is likely to be shorter and less intense than in the past. Climate change is disrupting the traditional wind patterns from the Sahara, making Harmattan less predictable rather than entirely absent.”

2. Is this usual? Has this happened before?

– “Traditionally, Harmattan starts around November and peaks between December and January, so this delay is not normal. However, it is no longer rare. Similar delayed or weak Harmattan seasons have been recorded repeatedly over the last three to five years. While short-term variations have always occurred, the increasing frequency of these delays’ points to long-term climate change rather than a one-off event.”

3. Any implications on crop production, besides fruiting for horticultural/tree crops?

– “Yes, the implications go beyond delayed fruiting. In Abia State and other cassava-producing areas, reduced Harmattan dryness can help soils retain moisture, which may initially benefit cassava since it tolerates wetter conditions better than many cereals. However, prolonged warmth and humidity increase the risk of pests and diseases, including fungal infections and cassava pests. Higher temperatures also raise evaporation rates, leading to water stress later in the season. For staple crops like maize, millet and sorghum, these conditions can reduce yields unless farmers adapt through better water management or improved crop varieties. Planting calendars may also shift, affecting overall farm planning. Soon, Seasonal Climate Predictions will be published with onset, peak, and cessation dates, which will guide farm activities and help determine optimal planting dates in Nigeria.”

4. Is this scenario the same for far north/northern region?

– “No, the situation is not the same across Nigeria. The far northern and northern regions (such as Borno, Yobe and Kano) are experiencing more typical Harmattan conditions, including dry, dusty winds, low humidity and cooler temperatures. However, even in these areas, the Harmattan is reported to be milder or slightly delayed compared to historical norms. In contrast, the southern region, including Abia State, has experienced a more noticeable delay, with continued high humidity and warmer temperatures. This regional difference highlights how climate change is affecting Nigeria unevenly. “

• Will it affect rainfall pattern? Researchers at NRCRI are currently working on rainfall pattern expected for 2026 in partnership with NIMET, and reported as follows:

“Analysis of post-Harmattan climatic responses—particularly rainfall onset, cessation, duration, intensity, and temperature – is ongoing. These aspects are being integrated into the upcoming Seasonal Climate Prediction developed in collaboration with NiMet, which will provide a more comprehensive outlook.”

Conclusion

While the complete absence of harmattan is worrisome as it suggests major alterations in natures balance, we may have to see what happens in the following

years to be conclusive on this. But while waiting we have to be prepared. We have to anticipate its effect on human health, agriculture, etc.

Appreciation

1. Dr. Ben Okoye, National Root Crops Umudike.
2. Dr. O. S. Chukwuemeka, Head Met Unit, NRCRI, Umudike.

Prof. Chinedum Nwajiuba (chnwajiuba@yahoo.de/+2348128498302) is Chairman, Board of West African Science Service Centre on Climate Change and Adapted land Use (WASCAL); Nigerian Environmental Study/Action Team (NEST); Development Planning and Research Institute (DPRI); Future Generations Institute (FGI)