A definition of ‘space weather’: ‘conditions on the sun and in the solar wind, magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health’.
Solar activity - current levels
Key (solar X-rays)
Normal: solar x-ray flux is quiet (< 1.00e-6 W/m^2).
Active: solar x-ray flux is active (>= 1.00e-6 W/m^2).
M class flare: an M class flare has occurred (x-ray flux >= 1.00e-5 W/m^2).
X class flare: an X class flare has occurred (x-ray flux >= 1.00e-4 W/m^2).
Mega flare: an unprecedented X-ray event has occurred (X-ray flux >= 1.00e-3 W/m^2).
Key (geomagnetic field)
Quiet: the geomagnetic field is quiet (Kp < 4).
Active: the geomagnetic field has been unsettled (Kp=4).
Storm: a geomagnetic storm has occurred (Kp>4).