Can you see the northern lights in Thunder Bay in June?

On dark, clear nights with enough activity. 30 of 30 nights at Thunder Bay have civil darkness, and 8% of past June days reached Kp 5.

How dark is Thunder Bay in June?

Thunder Bay averages 6.4 hours of civil night a night in June 2027, from 6 h 40 min on the 1st to 6 h 26 min on the last night.

How cloudy is Thunder Bay in June?

NASA POWER's 2001 to 2020 climatology gives Thunder Bay's 1 degree cell 70% mean cloud in June, against 70% for the whole year. It is an all-hours average, not a forecast.

What is the best night in June 2027 for aurora in Thunder Bay?

By darkness and moon alone, Jun 1, with 3 h 25 min of moon-free darkness inside 10 PM to 2 AM at Thunder Bay. Activity on that date will only be known hours ahead.

Is June or July better in Thunder Bay?

By civil night times the clear share, June scores 1.9 hours at Thunder Bay and July 2.4. July comes out ahead.

Thunder Bay · June 2027

Northern lights in Thunder Bay in June 2027

Answer

June gives Thunder Bay 6.4 hours of civil night on the 15th, the lightest month of its year, under 70% mean cloud. 8% of June days since 1996 reached Kp 5, enough for the oval edge to reach Thunder Bay.

6.4 h

civil night, average night

SunCalc for 48.38, -89.25; NASA POWER; GFZ Kp

June against the rest of the year

4.2

3.6

2.8

2.0

1.9

2.4

3.0

3.6

3.2

3.0

3.7

June cloud at Thunder Bay averages 70% in NASA POWER's 2001 to 2020 record, close to its yearly mean of 70%. August is Thunder Bay's clearest month at 64%. By civil night times clear sky, June scores 1.9 hours at Thunder Bay, 12th of 12. Duluth, 278 km away, averages 61%, clearer by 9 points.

Civil night at Thunder Bay starts June at 6 h 40 min and reaches 6 h 26 min by June 30, 0.2 hours shorter. No night keeps the 10 PM to 2 AM window fully dark at Thunder Bay. The sun never reaches 18 degrees down, so Thunder Bay gets no astronomical night in June.

June night by night

June opens toward a new moon on Jun 4, with full moon on Jun 18, in America/Toronto dates. Thunder Bay gets 90 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: Jun 1 (3 h 25 min), Jun 2 (3 h 24 min), Jun 3 (3 h 23 min).

1
9% lit
5.5 h
2
4% lit
6.0 h
3
1% lit
6.6 h
4
0% lit
6.6 h
New
5
3% lit
5.7 h
6
8% lit
4.9 h
7
16% lit
4.3 h
8
25% lit
3.9 h
9
36% lit
3.5 h
10
47% lit
3.2 h
11
58% lit
3.0 h
12
68% lit
2.6 h
13
78% lit
2.3 h
14
86% lit
1.9 h
15
92% lit
1.5 h
16
97% lit
0.9 h
17
99% lit
0.1 h
18
100% lit
0.0 h
Full
19
99% lit
0.3 h
20
96% lit
0.8 h
21
91% lit
1.3 h
22
85% lit
1.6 h
23
78% lit
1.9 h
24
70% lit
2.1 h
25
60% lit
2.4 h
26
51% lit
2.6 h
27
40% lit
2.9 h
28
30% lit
3.3 h
29
21% lit
3.7 h
30
12% lit
4.3 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 Junes

Thunder Bay needs Kp 5 for the average oval edge to sit overhead. 73 of the 900 June days from 1996 to 2025 (8%) reached it in the GFZ Potsdam record, 9th of 12 months; storm days with Kp 5 or more made up 8%. Thunder Bay sits at 57.1 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 5, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

June across Canada

Thunder Bay ranks 6th in Canada for civil night on June 15, behind Greater Sudbury at 6.8 hours. Coming from May (7.4 hours at Thunder Bay), June loses darkness, and the nights keep growing into July (6.9 hours on the 15th). The June solstice falls on June 21, 10:07 Thunder Bay time.

Civil night on June 15 and June cloud, month-page towns in Canada
Town	Civil night	Cloud
Greater Sudbury	6.8 h	60%
Trois-Rivières	6.8 h	63%
Sydney	6.8 h	70%
Québec	6.7 h	65%
St. John's	6.6 h	77%
Thunder Bay	6.4 h	70%
Saguenay	6.4 h	67%
Winnipeg	6.1 h	60%
Kelowna	6.1 h	67%
Lethbridge	6.1 h	60%
Regina	5.9 h	63%
Kamloops	5.9 h	68%

Darkness and moon, every night

Thunder Bay, June 2027: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Tue Jun 1	6 h 40 min	1 h 45 min	5 h 29 min	3 h 25 min	9%
Wed Jun 2	6 h 39 min	1 h 38 min	5 h 59 min	3 h 24 min	4%
Thu Jun 3	6 h 37 min	1 h 31 min	6 h 37 min	3 h 23 min	1%
Fri Jun 4	6 h 35 min	1 h 23 min	6 h 35 min	3 h 22 min	0%
Sat Jun 5	6 h 34 min	1 h 15 min	5 h 43 min	2 h 31 min	3%
Sun Jun 6	6 h 32 min	1 h 7 min	4 h 55 min	1 h 44 min	8%
Mon Jun 7	6 h 31 min	59 min	4 h 20 min	1 h 9 min	16%
Tue Jun 8	6 h 29 min	50 min	3 h 54 min	43 min	25%
Wed Jun 9	6 h 28 min	39 min	3 h 32 min	22 min	36%
Thu Jun 10	6 h 27 min	27 min	3 h 14 min	4 min	47%
Fri Jun 11	6 h 26 min	0 min	2 h 57 min	0 min	58%
Sat Jun 12	6 h 25 min	0 min	2 h 39 min	0 min	68%
Sun Jun 13	6 h 24 min	0 min	2 h 20 min	0 min	78%
Mon Jun 14	6 h 24 min	0 min	1 h 57 min	0 min	86%
Tue Jun 15	6 h 23 min	0 min	1 h 29 min	0 min	92%
Wed Jun 16	6 h 22 min	0 min	54 min	0 min	97%
Thu Jun 17	6 h 22 min	0 min	9 min	0 min	99%
Fri Jun 18	6 h 22 min	0 min	0 min	0 min	100%
Sat Jun 19	6 h 22 min	0 min	19 min	19 min	99%
Sun Jun 20	6 h 21 min	0 min	51 min	51 min	96%
Mon Jun 21	6 h 21 min	0 min	1 h 16 min	1 h 16 min	91%
Tue Jun 22	6 h 22 min	0 min	1 h 36 min	1 h 36 min	85%
Wed Jun 23	6 h 22 min	0 min	1 h 52 min	1 h 52 min	78%
Thu Jun 24	6 h 22 min	0 min	2 h 8 min	2 h 8 min	70%
Fri Jun 25	6 h 23 min	0 min	2 h 22 min	2 h 22 min	60%
Sat Jun 26	6 h 23 min	0 min	2 h 37 min	2 h 37 min	51%
Sun Jun 27	6 h 24 min	0 min	2 h 54 min	2 h 54 min	40%
Mon Jun 28	6 h 25 min	0 min	3 h 15 min	3 h 12 min	30%
Tue Jun 29	6 h 25 min	0 min	3 h 41 min	3 h 12 min	21%
Wed Jun 30	6 h 26 min	13 min	4 h 17 min	3 h 12 min	12%

Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Thunder Bay in June?: On dark, clear nights with enough activity. 30 of 30 nights at Thunder Bay have civil darkness, and 8% of past June days reached Kp 5.
How dark is Thunder Bay in June?: Thunder Bay averages 6.4 hours of civil night a night in June 2027, from 6 h 40 min on the 1st to 6 h 26 min on the last night.
How cloudy is Thunder Bay in June?: NASA POWER's 2001 to 2020 climatology gives Thunder Bay's 1 degree cell 70% mean cloud in June, against 70% for the whole year. It is an all-hours average, not a forecast.
What is the best night in June 2027 for aurora in Thunder Bay?: By darkness and moon alone, Jun 1, with 3 h 25 min of moon-free darkness inside 10 PM to 2 AM at Thunder Bay. Activity on that date will only be known hours ahead.
Is June or July better in Thunder Bay?: By civil night times the clear share, June scores 1.9 hours at Thunder Bay and July 2.4. July 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.