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Live cycle tracker

Solar Cycle 25 — Real-Time Progress Tracker

Solar Cycle 25 is the engine behind today's strong HF conditions. This tracker shows where the cycle stands, how NOAA's forecast compares to observed sunspot data, and what that means for real-world band openings.

Current solar state
SFI
137
SSN
74
K-Index
1
Current position in cycle
55% of the way from the December 2019 minimum toward the projected 2031 minimum
Peak window: 2025-2026
Dec 2019 minimumPeak window2031 minimum
Observed vs prediction

NOAA Solar Cycle 25 progress

The white line shows observed monthly sunspot number. The blue forecast corridor shows NOAA's current prediction envelope for Cycle 25.

Best observed month
216.0 SSN
Observed in Aug 24.
Highest monthly solar flux
245.6 SFU
NOAA monthly F10.7 peak observed in Aug 24.
Strongest X-ray flare
X8.7
May 14, 2024 from AR 3664. This was the largest flare of Cycle 25, though the source region was rotating off the west limb.
Strongest geomagnetic storm
Kp 9 / G5
May 10-12, 2024 delivered the cycle's most severe geomagnetic disturbance and the broadest aurora footprint in decades.

What this means for ham radio

Cycle 25 remains healthy, but the highest HF bands are more selective than during the strongest months of the peak.

When the cycle is strong, the F2 layer supports longer and more frequent openings on 10m and 15m. That is why recent months have produced easy worldwide contacts on the highest HF bands, especially around local midday and grayline.

As the cycle rolls off after the peak window, those top-end openings become more selective. Operators who understand the cycle phase can adjust expectations early instead of being surprised when 10m stops behaving like a daily band.

Records this cycle

Cycle 25 is not just stronger than forecast on paper. It has already produced one of the biggest monthly solar-flux runs of the modern era, the largest X-ray flare of the cycle, and a rare G5 geomagnetic storm that pushed aurora deep into the mid-latitudes.

Highest monthly solar flux
245.6 SFU

Aug 24 from NOAA's observed cycle index series.

Strongest X-ray flare
X8.7

AR 3664 on May 14, 2024. For operators, this is the benchmark blackout-class flare of Cycle 25.

Strongest geomagnetic storm
Kp 9 / G5

May 10-12, 2024. The storm hit polar HF hardest and confirmed how violent this cycle can still become.

Solar Cycle Comparison
Compare historic cycles (synthetic curves) vs today’s headline numbers.
Current: SFI 137 • SSN 74
Note: These curves are simplified for visualization; use real-time telemetry for current operating decisions.