* The probability of above-normal rainfall for January-February-March is still high — however, this likelihood is stronger in southern Malawi (58%), while the northern regions have a 50% chance
* Additionally, the probability of below-normal rainfall is higher over northern areas at 33% compared to the south at 17%
By Duncan Mlanjira
The 2024-2025 rainfall season was expected to be influenced by La Niña phenomenon, among other climate factors — with forecasts suggesting above-normal rainfall for the January-April 2025 period, but normal to below-normal rainfall during the October-November-December (OND) 2024 sub-season.
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But some rainfall forecasts were complicated by frequent false predictions due to delayed manifestation of the La Niña phenomenon, which did not become evident until January.
This analysis is contained in an update issued yesterday by the Department of Climate Change & Meteorological Services (DCCMS) in its review of the OND 2024 Sub-season.
“While the OND forecast (figure 1-left) predicted below-normal rainfall, the actual OND rainfall (figure 1-middle) was slightly lower than expected.
Figure 1: performance of rainfall during OND sub-season; left-OND forecast, middle-OND as observed, right-forecast verification
“Many districts in the country experienced below-normal rainfall. The deviation from the forecast is potentially explained by the delayed manifestation of the La Niña phenomenon, which did not become evident until January.
“The models accurately predicted rainfall in 26% (of districts, while in total a significant 78% experienced both accurate and partial matches (half correct, figure 1-right).
“The observed OND 2024 sub-season was both exceptionally dry and hot. It ranked as the third driest since 1971 (after 2021 and 1990) (figure 2), and the second hottest since 1970 after 2021 (figure 3).”
Figure 2: OND rainfall from 1970 to 2024
Figure 3: OND temperature anomaly from 1970 to 2024
Thus DCCMS notifies the public that “this was further complicated by frequent false onsets, where initial rainfall was followed by long dry spells”.
“The unusually high temperatures, 1.9 degrees above normal, intensified water loss and exacerbated the impacts of these dry conditions. However, OND 2024 remains the most severe on record, being both the driest and hottest.
“While this analysis focuses on the OND period, it’s important to recognise that the full year of 2024 marks the hottest since 1970, registering 2.9 degrees above the 1981-2010 baseline.”
This week’s weather update
On the update of January-February-March (JFM) 2025 sub-season, DCCMS says “the probability of above-normal rainfall is still high — however, this likelihood is stronger in southern Malawi (58%), while the northern regions have a 50% chance”.
“Additionally, the probability of below-normal rainfall is higher over northern areas at 33% compared to the south at 17% (Figure 4).
Figure 4: JFM 2025 sub-season rainfall forecast
Probabilistic forecast for January-February-March 2025 sub-season
“Malawi is divided into two regions, and the accompanying numbers represent probabilistic climate forecasts.
“Specifically, the top number indicates the probability of above-normal conditions, the middle number indicates the probability of normal conditions, and the bottom number indicates the probability of below-normal conditions.
“The most likely rainfall scenario for northern Malawi during JFM is above-normal, with a 50% probability. There’s a 33% chance of below-normal rainfall and a 17% chance of normal rainfall.
“Southern Malawi is most likely to experience above-normal rainfall during the JFM season, with a 58% probability. There’s a 25% chance of normal rainfall and a 17% chance of below-normal rainfall,” concludes the update.
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