| Solar cycle 24 | |
|---|---|
 ISES Solar Cycle 24 Sunspot Number Progression | |
| Sunspot data | |
| Start date | December 2008 |
| End date | December 2019 |
| Duration (years) | 11.0 |
| Max count | 81.8 |
| Max count month | April 2014 |
| Min count | 2.2 |
| Spotless days | 489 |
| Cycle chronology | |
| Previous cycle | Solar cycle 23 (1996-2008) |
| Next cycle | Solar cycle 25 (2019-present) |
Solar cycle 24 is the most recently completed solar cycle, the 24th since 1755, when extensive recording of solar sunspot activity began.[1][2] It began in December 2008 with a minimum smoothed sunspot number of 2.2,[3][failed verification] and ended in December 2019.[4] Activity was minimal until early 2010.[5][6] It reached its maximum in April 2014 with a 23 months smoothed sunspot number of 81.8.[7] This maximum value was substantially lower than other recent solar cycles, down to a level which had not been seen since cycles 12 to 15 (1878-1923).
- ^ Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
- ^ "The Sun: Did You Say the Sun Has Spots?". Space Today Online. Retrieved 12 August 2010.
- ^ SIDC formula
- ^ National Weather Service. "Hello Solar Cycle 25". Retrieved 2020-09-15.
- ^ Dr. Tony Phillips (2008-01-10). "Solar Cycle 24 Begins". NASA. Retrieved 2010-05-29.
- ^ Dr. Tony Phillips (2010-06-04). "As the Sun Awakens, NASA Keeps a Wary Eye on Space Weather". NASA. Retrieved 2013-05-18.
- ^ "2014 : maximum year for solar cycle 24 | SILSO". www.sidc.be. Retrieved 2018-03-14.