Seasonal Forecast

About our Rainfall Maps
Less than or = 40 way below normal
41 - 80 below normal
81 - 120 near normal
Greater than 120 above normal
Percent of Normal = Forecast Rainfall

Normal Rainfall
x 100%
Forecast Rainfall Analysis
Probabilistic Rainfall Forecast

Forecasting rainfall or temperature in probabilistic terms is a way of expressing uncertainty in the future weather/climate. When numerical probability values are assigned to the forecast, it is a way of indicating the amount of uncertainty in the forecast. Rather than say "below normal this July", we can say "30% chance to be below normal this July" when we think less rain is not so likely; or we can say "70% chance to be above normal this July " when we think great amount of rain is likely. Assigning a numerical value – a probability – to the occurrence of rainfall event allows us to quantify the uncertainty.

A probability forecast estimates the likelihood of occurrence of a specific event, which must be fully defined for the forecast to be verifiable. Events are defined by a time period and a specific location.

Probabilities are usually stated either as a percentage, which may range from 0 ("The event will definitely not occur") to 100 ("The event will definitely occur"). Values between 0 and 100 represent the different degrees of uncertainty.


A new forecast product that could be integrated by the agriculture sector in decision-making for the benefit of farmers and rice production in the country; Produced in the context of tailoring climate information for agricultural risk management applications;

Useful for other stakeholders (e.g., salt industry) for drying / and for agricultural produce predisposed to damage (post-harvest activities).

Dry day here is defined as a day with < 1 mm of rain (being issued February - April)

Wet day here is defined as a day with > or = 1 mm of rain (being issued May - January)

For Particulars, please contact:


Chief, Climate Monitoring and Prediction Section (CLIMPS)

Climatology and Agrometeorology Division (CAD), DOST-PAGASA

Trunkline No.: (02)8284-0800 local 4920 and 4921