Solar Conditions
HF Band ConditionsAs of Mon Aug 17, 2026 · 5:39 PM
Propagation conditions by band and time of day
| Band | Daytime | Nighttime | Outlook |
|---|
|
80m-40m
3.5 – 7.3 MHz
|
Poor |
Fair |
↘ May deteriorate in ~1h — Kp 4 expected |
| ↘ May deteriorate in ~1h — Kp 4 expected |
|
30m-20m
10.1 – 14.35 MHz
|
Good |
Good |
↘ May deteriorate in ~1h — Kp 4 expected |
| ↘ May deteriorate in ~1h — Kp 4 expected |
|
17m-15m
18.068 – 21.45 MHz
|
Fair |
Fair |
↘ May deteriorate in ~1h — Kp 4 expected |
| ↘ May deteriorate in ~1h — Kp 4 expected |
|
12m-10m
24.89 – 29.7 MHz
|
Fair |
Poor |
↘ May deteriorate in ~1h — Kp 4 expected |
| ↘ May deteriorate in ~1h — Kp 4 expected |
Outlook derived from the NOAA SWPC Kp forecast and 27-day solar flux outlook.
Solar Conditions
Key indices driving HF propagation right now
Solar Flux
124.0
Overall solar activity at 10.7cm. From 62.5 to 300; higher is better.
Sunspot Number
76
Derived from number of sunspots + groups. From 0 to 250; higher is better.
Geomagnetic Field
Unsettld
Overall activity of Earth's magnetic field, based on the K-index.
Solar Wind
404.3
Speed in km/s. Typically 0–1000 - lower is better; contributes to noise.
Noise Floor
S2-S3
Background noise contributed by solar activity.
Other Solar Conditions
Detailed indices for the propagation-curious
A-Index
10
Average geomagnetic activity. Lower is better.
K-Index
3.00
Geomagnetic field disturbance, 0 to 9. Lower is better.
X-Ray
C1.0
X-ray intensity in the ionosphere. A, B, C, M, X indicates magnitude.
304 Å Value
115.8
Total solar radiation at 30.4nm, emitted by ionized helium.
Proton Flux
46
Density of charged protons in the solar wind. Impacts the E-layer.
Electron Flux
1990
Density of charged electrons in the solar wind. Impacts the E-layer.
F2 Critical Freq
--
Highest frequency that reflects back from the F2 layer (MHz).
Max Usable Freq
--
Maximum usable frequency for sky-wave propagation (MHz).
Aurora Activity
4
Aurora activity level (0–100). Higher = more active aurora.
Aurora Latitude
63.9°
Southernmost latitude where aurora may be visible.
Magnetic Field
-3.5 nT
Interplanetary magnetic field. Negative Bz drives geomagnetic storms.
K-Index (Night)
No Report
Geomagnetic field disturbance overnight. Lower is better.
VHF & E-Skip Propagation
Sporadic-E and Auroral Openings
VHF Aurora
Band Closed
Northern Hemisphere
E-Skip 10m/6m
Band Closed
North America
E-Skip 10m/6m
Band Closed
Europe
E-Skip 6m
Band Closed
Europe
E-Skip 4m
Band Closed
Europe
3-Day Kp Forecast
NOAA SWPC prediction, 3-hour periods (UTC). Green = quiet, amber = unsettled, red = storm (G1+)
27-Day Outlook
NOAA SWPC predicted solar flux and geomagnetic activity · issued Aug 17 2026 UTC. Dots show your observed daily SFI as history accumulates.
Solar Flux — forecast vs observed
Largest Kp per day — forecast
Last 48 Hours
Hourly detail — the indices that move between daily updates
30-Day Trends
Daily averages from stored history