Analyzing long-term trends and variations in the sunspot cycle across Solar Cycles 1-24, and the rising phase of Solar Cycle 25

This research analyses long-term trends and variations in the sunspot cycle across Solar Cycles 1–24, along with the rising phase of Solar Cycle 25, to identify patterns and irregularities in solar activity. The sunspot cycle, typically lasting 9–14 years, plays a crucial role in solar-terrestrial interactions, with sunspots serving as indicators of solar activity that influence space weather and geomagnetic storms on Earth. During solar maxima, solar flares, coronal mass ejections, and solar proton events become more frequent, releasing significant energy into space. Conversely, solar minima are marked by fewer disturbances due to reduced heliospheric activity. The study examines historical sunspot data, spotless days, and solar cycle characteristics, uncovering significant correlations between key parameters. During this analysis, a good correlation, with a correlation coefficient (cc = 0.55) was found between spotless days and the length of solar cycles, suggesting that an increase in spotless days signals a declining phase of solar activity. Additionally, a strong correlation with a correlation coefficient (cc = 0.73) between the rise time to solar maximum and the maximum sunspot number indicates that a shorter rise time corresponds with a higher sunspot count at the peak of the cycle. The analysis also highlights historical trends, including a significant rise in spotless days in recent years, with 2019 recording 274 spotless days, the highest since 1913. This research observes that extended solar cycles, such as those during the Dalton Minimum, often follow shorter cycles, a trend seen in Solar Cycles 22 and 23, with Solar Cycle 24 showing a weaker performance. Predictions for Solar Cycle 25 indicate that it will be stronger than Solar Cycle 24, while Solar Cycles 26 and 27 are expected to be comparatively weaker. Forecasts estimate a maximum smoothed sunspot number in the range of 120–155, with the cycle peak in 2024. These results contribute to an improved understanding of solar cycle variability and provide important insights into the potential impacts of solar activity on space weather conditions and Earth’s climate system.