Week 21 / 2026 | May 18 – 24 | SFI 101 | SSN 46 | A 12 | K 4 | X-Ray B8.5
Summary
The downward trend continues: Solar Flux drops to 101 — the lowest value in weeks and a decrease of 19 points from week 20. The Sunspot Number falls to 46, with only two active regions of note. The sun is going through a quiet phase within Cycle 25.
The main story this week: A large coronal hole (#53, negative polarity) is facing Earth. The associated solar wind stream reaches us from May 15/16, pushing the Kp index to 4–5 (G1 storm level) on Friday and Saturday. From Monday, May 18, conditions are expected to calm down to Kp 2–3.
Flare activity is low — no noteworthy flares have been recorded in the past 72 hours. Active regions AR 4438 (N20W57, B-class, growing) and AR 4436 (N19W13, B-class, stable) are magnetically simple, producing at best C-class flares.
Band Forecast
SFI 101 is a significant dampener for the upper bands. 10 and 12 metres are essentially dead for F2 propagation without Sporadic E. 15 metres becomes a gamble. The good news: we’re in the middle of the Es season — sudden Sporadic E openings on 10m and 6m can compensate for the flux decline.
| Band | Day | Night | Notes |
|---|---|---|---|
| 160m | Poor | Poor | Season over — nights too short, high QRN |
| 80m | Fair | Fair | Intra-EU possible evenings, DX hopeless |
| 40m | Good | Good | Still solid, best nighttime DX band |
| 30m | Good | Good | Stable even at low flux — FT8 delivers |
| 20m | Very good | Fair | Still the main band — worldwide openings daytime |
| 17m | Fair to good | Poor | Shorter openings than at SFI 120, but still usable |
| 15m | Fair | Poor | Unreliable — wait for good days |
| 12m | Poor to fair | Poor | F2 essentially gone, hope for Sporadic E |
| 10m | Poor (F2) / Good (Es) | Poor | Es season! Sudden openings on 28 MHz possible |
Geomagnetic Forecast
The G1 storm from the weekend subsides early in the week. Quiet conditions from Wednesday.
| Day | Kp expected | Assessment |
|---|---|---|
| Mon, May 18 | 3–4 | Declining solar wind — still slightly unsettled |
| Tue, May 19 | 2–3 | Calming down |
| Wed, May 20 | 1–2 | Quiet — good DX conditions |
| Thu, May 21 | 1–2 | Quiet — best conditions of the week |
| Fri, May 22 | 2–3 | Stable |
| Sat, May 23 | 2–3 | Still quiet |
| Sun, May 24 | 2–3 | No disturbance expected |
Recommendations for the Coming Week
- 20 metres remains king: Even at SFI 101, 20m delivers reliable DX. Long paths to VK/ZL from 06:00 UTC, worldwide daytime, W evenings.
- Use Wed–Thu: Kp 1–2 expected — the quietest days, ideal for weak DX signals on 20m and 17m.
- Sporadic E season in full swing! The Es season is on — openings on 10m and 6m can occur at any time. Run FT8 on 50.313 MHz and 28.074 MHz, watch DX Cluster. Scan the FM broadcast band (88–108 MHz) as indicator.
- 40 and 30 metres evenings: When upper bands close, 40m and 30m take over. Good paths to NA and JA from 20:00 UTC.
- Mon/Tue patience: The declining G1 storm may still cause unsettled conditions on Monday. From Tuesday it improves.
Review: G1 Storm and Continued Flux Decline
The SFI decline from 159 (week 19) through 120 (week 20) to now 101 (week 21) shows a clear trend: the sun is going through a quieter phase within Cycle 25. This is normal — even at cycle maximum there are weeks of lower activity. A flux recovery in the coming weeks is likely.
Coronal hole #53 brings a G1 storm (Kp 4–5) on May 16/17, temporarily degrading propagation conditions. For VHF enthusiasts, however, the storm could enable aurora propagation on 2m — signals via the aurora towards Scandinavia. Listen on SSB 144.300 MHz for surprises.
Live Data
| Band | Tag ☀ | Nacht ☾ |
|---|---|---|
| 160m | Schlecht | Mäßig |
| 80–40m | Mäßig | Gut |
| 30–20m | Gut | Gut |
| 17–15m | Mäßig | Mäßig |
| 12–10m | Schlecht | Schlecht |
Further Reading
- MUF Maps (prop.kc2g.com)
- NOAA Space Weather Prediction Center
- HamQSL Solar Dashboard
- DXHeat DX Cluster
- SolarHam
Transparency Notice
This weather report was created with the assistance of AI (Claude, Anthropic) based on current data from NOAA/SWPC, HamQSL and SolarHam. All content has been reviewed by the oeradio.at editorial team. Corrections or additions to [email protected].
