A solar term is any of 24 points in traditional East Asian lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon. The points are spaced 15° apart along the ecliptic and are used by lunisolar calendars to stay synchronized with the seasons, which is crucial for agrarian societies. The solar terms are also used to calculate intercalary months in East Asian calendars; which month is repeated depends on the position of the sun at the time.

Online short-term solar power forecasting
Long-term variations of selected solar wind properties - IMP 6, 7, and 8 results
Long-term indirect indices of solar variability
Long term periodicity in solar wind velocity during the last three solar cycles
Evidence of a long-term trend in total solar irradiance
Evidence for long-term brightness changes of solar-type stars
Long-Term Solar Cycle Evolution: Review of Recent Developments
Long-term total solar irradiance variability during sunspot cycle 22
Online Short-term Solar Power Forecasting
Intermediate-term solar periodicities - 100-500 days