Seasonal Forecast for January 2025 – March 2025
Updated 2 January 2025
Northeast Monsoon conditions are expected to prevail over the ASEAN region during January 2025. During the Northeast Monsoon, the monsoon rain band is typically located south of the Equator, with low-level winds blowing mainly from the northeast or northwest over the region and the northern and southern ASEAN region experiences dry and wet weather conditions respectively. From late March onwards, the Northeast Monsoon conditions typically transitions into the inter-monsoon period associated with a gradual increase in shower activities over the northern ASEAN region.
For the January to March 2025 (JFM) period, models predict an increased chance of above-normal rainfall over much of the Maritime Continent, apart from over the southwestern region where near-normal rainfall is predicted. La Niña-like conditions are predicted for the next few months, although these conditions may not persist long enough to declare a La Niña event. La Niña conditions are typically associated with wetter than average conditions over much of Southeast Asia. Above-normal temperature is predicted over much of the ASEAN region for JFM 2025, apart from over the northeastern ASEAN region where near- to above-normal temperature is predicted.
The dry conditions over the northern ASEAN region that emerged in December 2024 are expected to strengthen during the outlook period. Despite above-normal rainfall outlook over some parts of the Mekong sub-region, further intensifications of hotspots and smoke haze activities, with risk of transboundary smoke haze occurrence, can still be expected over the sub-region. In the southern ASEAN region, the hotspot activity is likely to remain subdued under the prevailing wet weather conditions. However, during the drier phase of the Northeast Monsoon, which is typically observed during late January and February, isolated hotspots may develop in parts of the region.
The qualitative outlook is assessed for the region in general and based on the latest runs from models provided by the SEA RCC-Network LRF node. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.
For January 2025, above-normal rainfall is predicted over parts of the Maritime Continent.
For January 2025, above-normal rainfall is predicted over the northwestern Maritime Continent and parts of the eastern Maritime Continent, based on the multi-model ensemble (Figure 4). The ECMWF model (Figure 2) predicts near- to above-normal rainfall for most of the Maritime Continent, with the UK Met Office model (Figure 3) predicting near- to above-normal rainfall apart from over the equatorial region, where below- to near-normal rainfall is predicted. The NCEP model (Figure 1) predicts above-normal rainfall over northern Borneo and parts of the Philippines, with below- to near-normal rainfall for most of the rest of the Maritime Continent. Model skill is moderate to good for the parts of the Maritime Continent north of the equator and low to moderate for the parts to the south, in line with the better agreement between the models for the northern half of the region.
Over Mainland Southeast Asia, there is little agreement between the models (Figures 1 – 3). Model skill for this region is generally low at this time of the year.
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| Figure 1: Rainfall tercile summary predictions of NCEP model for January 2025 (contains modified Copernicus C3S information). | Figure 2: Rainfall tercile summary predictions of ECMWF model for January 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Rainfall tercile summary predictions of UK Met Office model for January 2025 (contains modified Copernicus C3S information). | Figure 4: Rainfall tercile summary predictions of multi-model ensemble model for January 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological rainfall’s lower tercile boundary for December based on CHIRPS (reference period: 1991-2020). | Figure 6: Average climatological rainfall’s upper tercile boundary for December based on CHIRPS (reference period: 1991-2020). |
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for rainfall, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.
For JFM 2025, above-normal rainfall is predicted over the Maritime Continent, apart from over the southwestern region.
For JFM 2025, above-normal rainfall is predicted over much of the Maritime Continent, based on the multi-model ensemble (Figure 4), apart from over the southwestern region where near-normal rainfall is predicted. The ECMWF and UK Met Office models (Figures 2 and 3) have the highest confidence for above-normal rainfall. The NCEP model (Figure 1) predicts a higher chance of above-normal rainfall over the parts of the Maritime Continent north of the equator. Model skill is moderate to good for most of the Maritime Continent.
For Mainland Southeast Asia, all three models (Figures 1 – 3) agree on above-normal rainfall over much of the region. However, it is the dry season for the region and the models’ skill is generally low.
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| Figure 1: Rainfall tercile summary predictions of NCEP model for JFM 2025 (contains modified Copernicus C3S information). | Figure 2: Rainfall tercile summary predictions of ECMWF model for JFM 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Rainfall tercile summary predictions of UK Met Office model for JFM 2025 (contains modified Copernicus C3S information). | Figure 4: Rainfall tercile summary predictions of multi-model ensemble model for JFM 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological rainfall’s lower tercile boundary for JFM based on CHIRPS (reference period: 1991-2020). | Figure 6: Average climatological rainfall’s upper tercile boundary for JFM based on CHIRPS (reference period: 1991-2020). |
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for rainfall, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.
For January 2025, near or above-normal temperature is predicted for Southeast Asia.
For January 2025, above-normal temperature is predicted based on the multi-model ensemble for most of the Maritime Continent (Figure 4). All three models agree on above-normal temperature over the Maritime Continent apart from over the Philippines, although the NCEP model (Figure 1) predicts above-normal temperature with a lower confidence compared to the ECMWF and UK Met Office models (Figures 2 and 3). Model skill is relatively good for the Maritime Continent.
For Mainland Southeast Asia, near-normal temperature is predicted for the eastern region with above-normal temperature predicted elsewhere, for all the three models (Figures 1 – 3). Model skill is low to moderate for Mainland Southeast Asia at this time of year.
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| Figure 1: Temperature tercile summary predictions of NCEP model for January 2025 (contains modified Copernicus C3S information). | Figure 2: Temperature tercile summary predictions of ECMWF model for January 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Temperature tercile summary predictions of UK Met Office model for January 2025 (contains modified Copernicus C3S information). | Figure 4: Temperature tercile summary predictions of multi-model ensemble model for January 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological temperature for January based on ERA5 (reference period: 1991-2020). |
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for temperature, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.
For JFM 2025, near- or above-normal temperature is predicted for Southeast Asia.
For JFM 2025, above-normal temperature is predicted for much of Southeast Asia, except for eastern Mainland Southeast Asia and the Philippines based on the multi-model ensemble (Figure 4). For eastern Mainland Southeast Asia and the Philippines, the NCEP model (Figure 1) predicts near-normal temperature, while the ECMWF and UK Met Office Models (Figures 2 and 3) predict near- to above-normal temperature. Model skill for above-normal temperature is relatively good for the Maritime Continent and moderate to good for Mainland Southeast Asia. For near-normal temperature, model skill is generally low to moderate.
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| Figure 1: Temperature tercile summary predictions of NCEP model for JFM 2025 (contains modified Copernicus C3S information). | Figure 2: Temperature tercile summary predictions of ECMWF model for JFM 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Temperature tercile summary predictions of UK Met Office model for JFM 2025 (contains modified Copernicus C3S information). | Figure 4: Temperature tercile summary predictions of multi-model ensemble model for JFM 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological temperature for JFM based on ERA5 (reference period: 1991-2020). |
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for temperature, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.
Frequently Asked Questions
What is a seasonal forecast?
A seasonal forecast provides forecast information about the general weather conditions at seasonal timescales up to several months ahead. Long range predictions rely on predicting components of the atmosphere and the oceans which show variations at large spatial and temporal scales. Among these key components is the sea-surface temperature – an important indicator in the El Niño Southern Oscillation (ENSO) cycle.
Example of probabilistic long range forecast using the multi-model ensemble. For areas nearby Peninsular Malaysia, the forecast is showing a probability of 50-70% of rainfall being in the below-normal (33%) tercile range. (Source: WMO LC LRF)
To account for the chaotic nature of the atmosphere, seasonal forecast adopts a probabilistic approach and the forecast weather condition is presented as an average over an extended period of time, usually with reference to climatology.
ASMC carries out monthly seasonal forecast predictions based on various seasonal model forecasts from the leading meteorological centres, supplemented by individual assessments from respective countries in South East Asia. The skillfulness of seasonal forecast relies greatly on the performance of seasonal models, which differ from one place to another and for different seasons of the year.
Receiver operating characteristic (ROC) score of UK GloSea5 seasonal hindcast for above-normal precipitation scenario for Dec – Feb (left) and May – Jul (right) over Asia region. Higher ROC score (indicated in red) means better model skill. (Source: UK Met Office)
For example, one way to assess the seasonal model skills is to examine the ROC score. From the figures above, we can see that ROC score map differs greatly from one season to another. During the period from Dec to Feb, a high ROC score region is observed mainly over the Philippines whereas during the period from May to Jul, a high ROC score region is observed over the near equatorial region such as Peninsular Malaysia and Sumatra.