Summary and Forecast

Solar Summary

(last updated 20 May 2026 23:30 UT)

Activity 20 May: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 20 May: 114/65

Solar Forecast

(last updated 20 May 2026 23:30 UT)

21 May 22 May 23 May Activity R0, chance of R1 R0, chance of R1 R0, chance of R1 Fadeouts Possible Possible Possible 10.7cm/SSN 110/60 108/58 115/66 COMMENT: Solar flare activity on UT day 20-May was at the R0 level, with no significant flaring activity. There are currently five numbered sunspot regions visible on the solar disk. AR4441 (N08W25, beta) showed some spot development over the UT day and is the largest and most magnetically complex region on the solar disk. All other sunspot regions are either stable or in decay. Solar flare activity is expected to be at the R0 level over 21-23 May, with a chance of R1. S0 solar radiation conditions were observed on UT day 20-May. S0 solar radiation conditions are expected over 21-23 May. No Earth-directed coronal mass ejections (CMEs) were observed on 20-May. The solar wind speed decreased over 21-May. The speed ranged from 435 to 540 km/s and is currently near 450 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 7 nT and the north-south IMF component (Bz) range was -4 to +5 nT. The solar wind speed is expected to continue to decline towards background levels and remain there over 21-23 May.

Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.