Space weather today in São João de Meriti

Space weather in São João de Meriti today

G1 minor geomagnetic storm forecast (NOAA, 2026-11-06 03:27 UTC). The planetary Kp index is 2 now and forecast to peak at Kp 5 in the next 24 hours. NOAA gives a 35% chance of R1–R2 radio blackouts today, 10% for R3 or stronger, and 5% for a solar radiation storm.

Radio: solar flares only black out HF radio on the half of Earth facing the Sun. The Sun is 49° below the horizon in São João de Meriti now (12:35 am local time). The biggest flare in the past 24 hours was M3.5 at 3:33 pm local time, while São João de Meriti was in daylight, so HF radio here may have faded briefly. HF radio is mainly hit by daytime solar flares (radio blackouts).

GPS and power: Near the magnetic equator, GPS signals can flicker after sunset (equatorial scintillation), most often near solar maximum and around the equinoxes. Power grid effects are very unlikely at this latitude.

Aurora chance tonight in São João de Meriti

Unlikely tonight (Kp 2 forecast; São João de Meriti needs an extreme Kp 9 storm). At 14.7° S geomagnetic, São João de Meriti is far from the auroral oval; only extreme Kp 9 (G5) storms such as May 2024 bring the aurora into view, mostly to cameras.

At the forecast Kp 5, the aurora's visible edge stays about 4,276 km south of São João de Meriti.

NOAA 3-day space weather forecast

Chances that NOAA issues each level somewhere on Earth. Radio blackouts only affect the sunlit side; geomagnetic storms are global but strongest near the poles.

Strongest solar flares this week

C-class and stronger flares from the past 7 days, local time in São João de Meriti.

• M3.5 flare peak Thu 3:33 pm, R1 minor radio blackout
• C5.6 flare peak Thu 11:51 pm
• C2.9 flare peak Thu 6:34 pm
• C2.5 flare peak Thu 9:24 pm
• C2.2 flare peak Wed 2:34 pm
• C1.3 flare peak Thu 7:31 pm
• C1.2 flare peak Thu 7:21 pm
• C1.2 flare peak Wed 3:54 am
• C1.1 flare peak Thu 2:00 pm
• C1.1 flare peak Tue 7:39 pm

What the scales mean

Space weather is the Sun's effect on Earth. NOAA rates it on three 1–5 scales. R (radio blackouts) comes from solar flares: X-rays reach Earth in 8 minutes and disrupt HF radio on the sunlit side for minutes to hours. S (solar radiation storms) comes from energetic protons a few hours later, a hazard for satellites, polar flights and astronauts. G (geomagnetic storms) comes 1–3 days after a coronal mass ejection or a fast solar-wind stream hits the magnetic field: it drives the aurora and can upset GPS, HF radio and power grids.

The Kp index (0–9) measures geomagnetic activity in 3-hour blocks: Kp 5 is a G1 storm, Kp 6 G2, Kp 7 G3, Kp 8 G4 and Kp 9 G5. Flares are classed A, B, C, M and X by peak X-ray brightness, each class ten times the one before; M1 flares cause R1 blackouts and X1 flares R3.

Space weather for nearby cities

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• Space weather Rio de Janeiro
• Space weather Niterói
• Space weather Juiz de Fora
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More sky pages

• Space weather today (worldwide)
• Aurora forecast
• Meteor showers

Guides

• Solar Flares and Geomagnetic Storms Explained: R, S and G Scales
• What Kp Index Do You Need to See the Northern Lights?
• How to See the Northern Lights Tonight: A Practical Guide
• GPS Jamming and Spoofing Explained: How Maps Detect It