Analysis of Short-term Solar Activity Variability and Estimating the Timings of the Next Enhanced Bursts

Abstract We present a novel hybrid forecasting strategy combining numerical, statistical, and machine learning–based forecasting to detect the occurrence of the next enhanced solar activity bursts. These enhanced bursts are called “space weather seasons,” which occur on intermediate timescales (6–18 months). Monthly smoothed sunspot number (SSN) data from 1878 to 2025 are analyzed using Gaussian fitting techniques to identify burst events and their properties such as amplitude and duration. The SSN data are divided into training, test, and forecast, which shows hindcast and forecast. Each hemisphere is modeled via a seasonal autoregressive integrated moving average approach, refined with an asymmetric Gaussian override to capture rapid burst rise and gradual decay, and burst amplitudes and duration are predicted using a random forest regression model. This hybrid approach successfully hindcasts burst timing in between 2024 November and 2025 May, with a peak SSN of ∼70 around 2025 March for the Northern Hemisphere. The next burst in the Northern Hemisphere is forecast to be in 2025 December with a slightly lower SSN of 60. By contrast, the Southern Hemisphere shows relatively complicated behavior, where the bursts show multiple amplitudes starting approximately in 2024 October and ending in 2025 October. The main burst shows an amplitude of 130 SSN. The next burst in the Southern Hemisphere is forecast to occur approximately in 2025 December. Combining SSN properties in both hemispheres, we find that the total SSN is mainly influenced by a stronger cycle in the Southern Hemisphere.