Saint-Jean-sur-Richelieu · August 2027
Northern lights in Saint-Jean-sur-Richelieu in August 2027
Answer
August against the rest of the year
August cloud at Saint-Jean-sur-Richelieu averages 57% in NASA POWER's 2001 to 2020 record, 8 points clearer than its yearly mean. September is Saint-Jean-sur-Richelieu's clearest month at 54%. By civil night times clear sky, August scores 3.8 hours at Saint-Jean-sur-Richelieu, 6th of 12. Trois-Rivières, 128 km away, averages 59%, cloudier by 2 points.
Civil night at Saint-Jean-sur-Richelieu starts August at 8 h 3 min and reaches 9 h 35 min by August 31 as the nights lengthen by 1.5 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 6.0 hours on the 15th.
August night by night
August opens toward a new moon on Aug 2 and Aug 31, with full moon on Aug 17, in America/Toronto dates. Saint-Jean-sur-Richelieu gets 137 hours of civil night with the moon below the horizon across the month. The best of them for moon-free darkness inside 10 PM to 2 AM: Aug 1 (4 h), Aug 2 (4 h), Aug 3 (4 h).
- 1
0% lit
8.1 h
- 2
1% lit
8.1 h
- 3
5% lit
8.2 h
- 4
11% lit
7.8 h
- 5
19% lit
7.5 h
- 6
29% lit
7.1 h
- 7
39% lit
6.8 h
- 8
50% lit
6.3 h
- 9
60% lit
5.8 h
- 10
69% lit
5.1 h
- 11
78% lit
4.3 h
- 12
85% lit
3.4 h
- 13
91% lit
2.4 h
- 14
96% lit
1.3 h
- 15
99% lit
0.3 h
- 16
100% lit
0.0 h
- 17
99% lit
0.0 h
- 18
97% lit
0.0 h
- 19
93% lit
0.1 h
- 20
87% lit
0.5 h
- 21
79% lit
0.8 h
- 22
70% lit
1.2 h
- 23
60% lit
1.8 h
- 24
49% lit
2.4 h
- 25
38% lit
3.3 h
- 26
28% lit
4.3 h
- 27
18% lit
5.6 h
- 28
10% lit
7.0 h
- 29
4% lit
8.5 h
- 30
1% lit
9.5 h
- 31
0% lit
9.6 h
Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.
Activity in past Augusts
Saint-Jean-sur-Richelieu needs Kp 6 for the average oval edge to sit overhead. 28 of the 930 August days from 1996 to 2025 (3%) reached it in the GFZ Potsdam record, 8th of 12 months; storm days with Kp 5 or more made up 11%. Saint-Jean-sur-Richelieu sits at 54.5 degrees geomagnetic. The lowest NOAA storm level whose typical viewing latitude reaches it is G3 (Kp = 7). By SWPC's rule the average oval edge is overhead only at Kp 6.
August across Canada
No month-page town in Canada has more civil night on August 15 than Saint-Jean-sur-Richelieu; the national median is 8.2 hours. Coming from July (7.4 hours at Saint-Jean-sur-Richelieu), August adds darkness, and the nights keep growing into September (10.4 hours on the 15th).
| Town | Civil night | Cloud |
|---|---|---|
| Saint-Jean-sur-Richelieu | 8.8 h | 57% |
| Trois-Rivières | 8.7 h | 59% |
| Sydney | 8.7 h | 65% |
| Québec | 8.6 h | 60% |
| Greater Sudbury | 8.6 h | 56% |
| St. John's | 8.5 h | 72% |
| Saguenay | 8.4 h | 68% |
| Thunder Bay | 8.4 h | 64% |
| Winnipeg | 8.3 h | 52% |
| Kelowna | 8.3 h | 45% |
| Lethbridge | 8.3 h | 51% |
| Regina | 8.2 h | 53% |
Darkness and moon, every night
| Night | Civil | Astronomical | Moon-free dark | Moon-free, 10 PM to 2 AM | Moon lit |
|---|---|---|---|---|---|
| Sun Aug 1 | 8 h 3 min | 4 h 56 min | 8 h 3 min | 4 h | 0% |
| Mon Aug 2 | 8 h 6 min | 5 h 1 min | 8 h 6 min | 4 h | 1% |
| Tue Aug 3 | 8 h 9 min | 5 h 5 min | 8 h 9 min | 4 h | 5% |
| Wed Aug 4 | 8 h 12 min | 5 h 9 min | 7 h 48 min | 4 h | 11% |
| Thu Aug 5 | 8 h 15 min | 5 h 13 min | 7 h 28 min | 4 h | 19% |
| Fri Aug 6 | 8 h 18 min | 5 h 18 min | 7 h 8 min | 4 h | 29% |
| Sat Aug 7 | 8 h 20 min | 5 h 22 min | 6 h 45 min | 3 h 36 min | 39% |
| Sun Aug 8 | 8 h 23 min | 5 h 26 min | 6 h 19 min | 3 h 8 min | 50% |
| Mon Aug 9 | 8 h 26 min | 5 h 31 min | 5 h 47 min | 2 h 35 min | 60% |
| Tue Aug 10 | 8 h 29 min | 5 h 35 min | 5 h 8 min | 1 h 55 min | 69% |
| Wed Aug 11 | 8 h 32 min | 5 h 39 min | 4 h 20 min | 1 h 6 min | 78% |
| Thu Aug 12 | 8 h 35 min | 5 h 44 min | 3 h 25 min | 9 min | 85% |
| Fri Aug 13 | 8 h 38 min | 5 h 48 min | 2 h 24 min | 0 min | 91% |
| Sat Aug 14 | 8 h 41 min | 5 h 52 min | 1 h 20 min | 0 min | 96% |
| Sun Aug 15 | 8 h 44 min | 5 h 56 min | 16 min | 0 min | 99% |
| Mon Aug 16 | 8 h 48 min | 6 h 1 min | 0 min | 0 min | 100% |
| Tue Aug 17 | 8 h 51 min | 6 h 5 min | 0 min | 0 min | 99% |
| Wed Aug 18 | 8 h 54 min | 6 h 9 min | 0 min | 0 min | 97% |
| Thu Aug 19 | 8 h 57 min | 6 h 13 min | 8 min | 0 min | 93% |
| Fri Aug 20 | 9 h | 6 h 18 min | 28 min | 0 min | 87% |
| Sat Aug 21 | 9 h 3 min | 6 h 22 min | 49 min | 0 min | 79% |
| Sun Aug 22 | 9 h 6 min | 6 h 26 min | 1 h 14 min | 0 min | 70% |
| Mon Aug 23 | 9 h 9 min | 6 h 30 min | 1 h 45 min | 6 min | 60% |
| Tue Aug 24 | 9 h 13 min | 6 h 34 min | 2 h 25 min | 44 min | 49% |
| Wed Aug 25 | 9 h 16 min | 6 h 38 min | 3 h 16 min | 1 h 33 min | 38% |
| Thu Aug 26 | 9 h 19 min | 6 h 42 min | 4 h 21 min | 2 h 36 min | 28% |
| Fri Aug 27 | 9 h 22 min | 6 h 46 min | 5 h 38 min | 3 h 51 min | 18% |
| Sat Aug 28 | 9 h 25 min | 6 h 50 min | 7 h 2 min | 4 h | 10% |
| Sun Aug 29 | 9 h 29 min | 6 h 55 min | 8 h 29 min | 4 h | 4% |
| Mon Aug 30 | 9 h 32 min | 6 h 59 min | 9 h 32 min | 4 h | 1% |
| Tue Aug 31 | 9 h 35 min | 7 h 3 min | 9 h 35 min | 4 h | 0% |
Questions
- Can you see the northern lights in Saint-Jean-sur-Richelieu in August?
- On dark, clear nights with enough activity. 31 of 31 nights at Saint-Jean-sur-Richelieu have civil darkness, and 3% of past August days reached Kp 6.
- How dark is Saint-Jean-sur-Richelieu in August?
- Saint-Jean-sur-Richelieu averages 8.8 hours of civil night a night in August 2027, from 8 h 3 min on the 1st to 9 h 35 min on the last night.
- How cloudy is Saint-Jean-sur-Richelieu in August?
- NASA POWER's 2001 to 2020 climatology gives Saint-Jean-sur-Richelieu's 1 degree cell 57% mean cloud in August, against 65% for the whole year. It is an all-hours average, not a forecast.
- What is the best night in August 2027 for aurora in Saint-Jean-sur-Richelieu?
- By darkness and moon alone, Aug 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Saint-Jean-sur-Richelieu. Activity on that date will only be known hours ahead.
- Is August or September better in Saint-Jean-sur-Richelieu?
- By civil night times the clear share, August scores 3.8 hours at Saint-Jean-sur-Richelieu and September 4.8. September comes out ahead.
Sources and verification
- SunCalchttps://github.com/mourner/suncalc
- NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
- GFZ Potsdam Kp indexhttps://kp.gfz.de/en/data
- NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora
Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.