3-day aurora forecast
NOAA's forecast of the Kp index for the next three days, in 3-hour blocks, and what it means for places in the US.
In short: the highest Kp in the next 3 days is 4.00, below storm level. Good for Alaska and Canada, possible along the Canadian border on the best night.
| UTC block | Sun, Oct 25 | Mon, Oct 26 | Tue, Oct 27 |
|---|---|---|---|
| 00-03 UTC | n/a | 3.00 | 1.67 |
| 03-06 UTC | n/a | 2.00 | 1.33 |
| 06-09 UTC | 3.00 | 2.00 | 1.33 |
| 09-12 UTC | 3.33 | 2.00 | 1.33 |
| 12-15 UTC | 4.00 | 2.00 | 1.33 |
| 15-18 UTC | 3.33 | 2.00 | 1.33 |
| 18-21 UTC | 4.00 | 2.00 | 1.67 |
| 21-00 UTC | 3.00 | 2.33 | 1.67 |
UTC to US time: 00-03 UTC is 7 pm to 10 pm Eastern (8 pm to 11 pm while daylight saving time is on, 4 pm to 7 pm Pacific in winter). The US night falls mostly in the 00 to 12 UTC blocks.
What it means tonight
| Place | Kp needed | Max Kp after dark | Tonight |
|---|---|---|---|
| Fairbanks, AK | Kp 0 to 1 (most dark, clear nights) | 2.00 | Clouds in the way |
| International Falls, MN | Kp 4 | 3.00 | Low chance |
| Marquette, MI | Kp 4 | 3.00 | Unlikely |
| Presque Isle, ME | Kp 4 | 3.00 | Low chance |
| Bellingham, WA | Kp 5 | 2.00 | Unlikely |
| Plattsburgh, NY | Kp 5 | 3.00 | Unlikely |
| Chicago, IL | Kp 7 | 3.00 | Unlikely |
| Denver, CO | Kp 8 | 3.00 | Clouds in the way |
How to read the forecast
Each number is the Kp NOAA expects as the highest value in that 3-hour block. Values come in thirds: 4.67 is written 5-, 5.00 is 5, 5.33 is 5+. A forecast of 5 or more means a geomagnetic storm watch on the NOAA G scale.
The 3-day forecast is good at the general level of activity, but storms from a coronal mass ejection can arrive hours earlier or later than expected, and they can be weaker or stronger. When a storm is under way, the live Kp index and the aurora map tell you more than the forecast.
Source: NOAA Space Weather Prediction Center, 3-day geomagnetic forecast (public domain). Unofficial copy; check the NOAA forecast for official watches and warnings.
Page built: October 25, 2026.