Seasonal Forecast for February 2025 – April 2025
Updated 3 February 2025
Under the prevailing Northeast Monsoon, the northern and southern ASEAN region continues to experience their traditional dry and wet season respectively as the monsoon rainband is located south of the Equator, with prevailing low-level winds blowing from the northwest or northeast over the region. While showers are typical over the southern ASEAN region, dry spells can be expected during the dry phase of the Northeast Monsoon, typically during February. Around late March or early April, the prevailing low-level winds gradually weaken and become light and variable in direction as the Northeast Monsoon transitions into inter-monsoon conditions.
For February, below-to near-normal rainfall is predicted over the equatorial region, with above-normal predicted over the rest of the Maritime Continent. For the February to March 2025 (FMA) period overall, models predict an increased chance of above-normal rainfall over the northern half of the Maritime Continent, while below-normal rainfall is predicted over the equatorial region. There is also an increase in chance of above-normal rainfall over parts of Mainland Southeast Asia. La Niña conditions are now present, with a transition to ENSO neutral predicted by April-May 2025. 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 FMA 2025, apart from over eastern Mainland Southeast Asia where near-normal temperature is predicted.
Despite an above-normal rainfall outlook for some parts of the Mekong sub-region during the outlook period, further intensification of hotspots and smoke haze activities, along with a heightened risk of transboundary smoke haze occurrence, can still be expected over the sub-region as overall dry conditions dominate the area. While the overall hotspot activity is likely to remain subdued under the prevailing wet weather conditions over the southern ASEAN region, hotspot activity may increase during the dry phase of the Northeast Monsoon conditions, particularly in areas where below-normal rainfall is predicted.
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 February 2025, below- to near-normal rainfall is predicted over the equatorial region, with above-normal rainfall is predicted over the rest of the Maritime Continent.
For February 2025, above-normal rainfall is predicted over much of the Maritime Continent, based on the multi-model ensemble (Figure 4). All models predict above-normal rainfall for much of the Maritime Continent (Figures 1-3), with the NCEP model also predicts below-normal rainfall over parts of Sumatra, western Borneo and Sulawesi (Figure 1), while the ECMWF and UK Met Office models (Figures 2 and 3) predict below- to near-normal rainfall over the southern half of Sumatra, southern Borneo, Sulawesi and much of Papua. Model skill is low to moderate over most of the region, except for over the Philippines where the model skill is overall good.
Over Mainland Southeast Asia, above-normal rainfall is predicted over the southeastern parts of the region, based on the multi-model ensemble (Figure 4), although this is the dry season for this region (Figure 6) and the rainfall anomalies are predicted to be small. Elsewhere in the region, the models disagree on the dominant tercile rainfall. For above-normal rainfall over the southeastern parts of Mainland Southeast Asia the model skill is moderate.
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| Figure 1: Rainfall tercile summary predictions of NCEP model for February 2025 (contains modified Copernicus C3S information). | Figure 2: Rainfall tercile summary predictions of ECMWF model for February 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Rainfall tercile summary predictions of UK Met Office model for February 2025 (contains modified Copernicus C3S information). | Figure 4: Rainfall tercile summary predictions of multi-model ensemble model for February 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological rainfall’s lower tercile boundary for February based on CHIRPS (reference period: 1991-2020). | Figure 6: Average climatological rainfall’s upper tercile boundary for February 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 FMA 2025, above-normal rainfall is predicted over the northern half of the Maritime Continent, with below- to near-normal rainfall predicted over the equatorial region. There is also an increase in chance of above-normal rainfall over parts of Mainland Southeast Asia.
For FMA 2025, above-normal rainfall is predicted over the northern half of the Maritime Continent, based on the multi-model ensemble (Figure 4). Elsewhere, below- to near-normal rainfall is predicted over much of the equatorial region. The NCEP model (Figure 1), has the highest confidence of below-normal rainfall for this region compared to the ECMWF and UK Met Office models (Figures 2 and 3). All three models predict the highest chance of above-normal rainfall over the northeastern Maritime Continent. For the southernmost part of the Maritime Continent, no dominant tercile is predicted. Skill over the northern half of the Maritime Continent is relatively good, while skill for below-normal rainfall over the equatorial region is low to moderate.
For Mainland Southeast Asia, above-normal rainfall is predicted over most of the region, based on the multi-model ensemble (Figure 4). The UK Met Office model predicts an increased chance of above-normal rainfall over all of Mainland Southeast Asia, while the ECMWF predicts above-normal rainfall over central and southern parts, and the NCEP model predicts above-normal rainfall over parts of central and northern Mainland Southeast Asia. Model skill for above-normal rainfall is overall moderate for Mainland Southeast Asia.
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| Figure 1: Rainfall tercile summary predictions of NCEP model for FMA 2025 (contains modified Copernicus C3S information). | Figure 2: Rainfall tercile summary predictions of ECMWF model for FMA 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Rainfall tercile summary predictions of UK Met Office model for FMA 2025 (contains modified Copernicus C3S information). | Figure 4: Rainfall tercile summary predictions of multi-model ensemble model for FMA 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological rainfall’s lower tercile boundary for FMA based on CHIRPS (reference period: 1991-2020). | Figure 6: Average climatological rainfall’s upper tercile boundary for FMA 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 February 2025, near or above-normal temperature is predicted for most of the Maritime Continent and western Mainland Southeast Asia.
For February 2025, above-normal temperature is predicted over most parts of the Maritime Continent, except for over the Malay Peninsula, based on the multi-model ensemble (Figure 4). All three models agree on above-normal temperature over the eastern and southwestern Maritime Continent (Figures 1-3), while only the UK Met Office model (Figure 2) also predicts above-normal temperature over the Malay Peninsula. The NCEP model (Figure 1) shows disagreement with other models also over parts of the southern Maritime Continent and the Philippines where it predicts near-normal temperature, while the UK Met Office and ECMWF modes (Figures 2 and 3) predict above-normal temperature over most of these regions. Model skill is relatively good for the Maritime Continent.
For Mainland Southeast Asia, above-normal temperature is predicted for the western region, based on the multi-model ensemble (Figure 4), with a disagreement between the models on the dominant tercile elsewhere (Figures 1 – 3). Model skill is moderate for Mainland Southeast Asia at this time of year.
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| Figure 1: Temperature tercile summary predictions of NCEP model for February 2025 (contains modified Copernicus C3S information). | Figure 2: Temperature tercile summary predictions of ECMWF model for February 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Temperature tercile summary predictions of UK Met Office model for February 2025 (contains modified Copernicus C3S information). | Figure 4: Temperature tercile summary predictions of multi-model ensemble model for February 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological temperature for February 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 FMA 2025, near- or above-normal temperature is predicted for much of Southeast Asia.
For FMA 2025, above-normal temperature is predicted for much of Southeast Asia, except for eastern Mainland Southeast Asia based on the multi-model ensemble (Figure 4). For eastern Mainland Southeast Asia, all models predict near-normal temperature (Figures 1-3). For the Maritime Continent, all models agree on above-normal temperature for the region, apart from over the Philippines, where the ECMWF and UK Met Office models (Figures 2 and 3) predict above-normal temperature, while the NCEP model (Figure 1) predicts near-normal temperature. Model skill for above-normal temperature is relatively good for the Maritime Continent and 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 FMA 2025 (contains modified Copernicus C3S information). | Figure 2: Temperature tercile summary predictions of ECMWF model for FMA 2025 (contains modified Copernicus C3S information). |
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| Figure 3: Temperature tercile summary predictions of UK Met Office model for FMA 2025 (contains modified Copernicus C3S information). | Figure 4: Temperature tercile summary predictions of multi-model ensemble model for FMA 2025 (contains modified Copernicus C3S information). |
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| Figure 5: Average climatological temperature for FMA 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.