Tri-Cities · July 2027
Northern lights in Tri-Cities in July 2027
Answer
July against the rest of the year
July cloud at Tri-Cities averages 26% in NASA POWER's 2001 to 2020 record, 30 points clearer than its yearly mean. No month at Tri-Cities is clearer. By civil night times clear sky, July scores 5.4 hours at Tri-Cities, 3rd of 12. Seattle, 282 km away, averages 47%, cloudier by 21 points.
Civil night at Tri-Cities starts July at 6 h 53 min and reaches 7 h 54 min by July 31 as the nights lengthen by 1.0 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 3.5 hours on the 15th.
July night by night
July opens toward a new moon on Jul 3, with full moon on Jul 18, in America/Los_Angeles dates. Tri-Cities gets 108 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: Jul 1 (4 h), Jul 2 (4 h), Jul 3 (4 h).
- 1
5% lit
5.6 h
- 2
1% lit
6.7 h
- 3
0% lit
6.9 h
- 4
2% lit
6.8 h
- 5
7% lit
6.3 h
- 6
14% lit
5.9 h
- 7
24% lit
5.5 h
- 8
34% lit
5.2 h
- 9
45% lit
4.9 h
- 10
56% lit
4.5 h
- 11
66% lit
4.2 h
- 12
75% lit
3.7 h
- 13
83% lit
3.1 h
- 14
90% lit
2.4 h
- 15
95% lit
1.6 h
- 16
98% lit
0.6 h
- 17
100% lit
0.0 h
- 18
100% lit
0.0 h
- 19
98% lit
0.1 h
- 20
94% lit
0.4 h
- 21
89% lit
0.7 h
- 22
82% lit
1.0 h
- 23
74% lit
1.3 h
- 24
64% lit
1.6 h
- 25
54% lit
2.0 h
- 26
44% lit
2.4 h
- 27
33% lit
3.0 h
- 28
23% lit
3.7 h
- 29
14% lit
4.7 h
- 30
7% lit
6.0 h
- 31
2% lit
7.4 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 Julys
Tri-Cities needs Kp 7 for the average oval edge to sit overhead. 10 of the 930 July days from 1996 to 2025 (1%) reached it in the GFZ Potsdam record, 8th of 12 months; storm days with Kp 5 or more made up 9%. Tri-Cities sits at 52.1 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 7.
July across United States
Tri-Cities ranks 4th in United States for civil night on July 15, behind Buffalo at 7.8 hours. Coming from June (6.8 hours at Tri-Cities), July adds darkness, and the nights keep growing into August (8.7 hours on the 15th).
| Town | Civil night | Cloud |
|---|---|---|
| Buffalo | 7.8 h | 56% |
| Portland, Maine | 7.6 h | 55% |
| Minneapolis | 7.4 h | 46% |
| Tri-Cities | 7.3 h | 26% |
| Duluth | 7.2 h | 51% |
| Fargo | 7.1 h | 48% |
| Seattle | 7.0 h | 47% |
| Juneau | 4.1 h | 81% |
| Anchorage | 2.1 h | 83% |
| Eagle River | 2.0 h | 83% |
| Fairbanks | 0.0 h | 77% |
Darkness and moon, every night
| Night | Civil | Astronomical | Moon-free dark | Moon-free, 10 PM to 2 AM | Moon lit |
|---|---|---|---|---|---|
| Thu Jul 1 | 6 h 53 min | 2 h 36 min | 5 h 36 min | 4 h | 5% |
| Fri Jul 2 | 6 h 54 min | 2 h 39 min | 6 h 44 min | 4 h | 1% |
| Sat Jul 3 | 6 h 55 min | 2 h 42 min | 6 h 55 min | 4 h | 0% |
| Sun Jul 4 | 6 h 56 min | 2 h 45 min | 6 h 48 min | 4 h | 2% |
| Mon Jul 5 | 6 h 57 min | 2 h 48 min | 6 h 16 min | 3 h 46 min | 7% |
| Tue Jul 6 | 6 h 58 min | 2 h 51 min | 5 h 52 min | 3 h 21 min | 14% |
| Wed Jul 7 | 7 h | 2 h 55 min | 5 h 31 min | 2 h 59 min | 24% |
| Thu Jul 8 | 7 h 1 min | 2 h 58 min | 5 h 12 min | 2 h 39 min | 34% |
| Fri Jul 9 | 7 h 3 min | 3 h 2 min | 4 h 53 min | 2 h 20 min | 45% |
| Sat Jul 10 | 7 h 5 min | 3 h 5 min | 4 h 33 min | 1 h 59 min | 56% |
| Sun Jul 11 | 7 h 6 min | 3 h 9 min | 4 h 11 min | 1 h 35 min | 66% |
| Mon Jul 12 | 7 h 8 min | 3 h 13 min | 3 h 43 min | 1 h 6 min | 75% |
| Tue Jul 13 | 7 h 10 min | 3 h 17 min | 3 h 9 min | 31 min | 83% |
| Wed Jul 14 | 7 h 12 min | 3 h 21 min | 2 h 26 min | 0 min | 90% |
| Thu Jul 15 | 7 h 14 min | 3 h 26 min | 1 h 35 min | 0 min | 95% |
| Fri Jul 16 | 7 h 16 min | 3 h 30 min | 36 min | 0 min | 98% |
| Sat Jul 17 | 7 h 18 min | 3 h 34 min | 0 min | 0 min | 100% |
| Sun Jul 18 | 7 h 20 min | 3 h 38 min | 0 min | 0 min | 100% |
| Mon Jul 19 | 7 h 23 min | 3 h 43 min | 3 min | 0 min | 98% |
| Tue Jul 20 | 7 h 25 min | 3 h 47 min | 24 min | 0 min | 94% |
| Wed Jul 21 | 7 h 27 min | 3 h 52 min | 42 min | 2 min | 89% |
| Thu Jul 22 | 7 h 30 min | 3 h 56 min | 1 h | 18 min | 82% |
| Fri Jul 23 | 7 h 32 min | 4 h 1 min | 1 h 17 min | 35 min | 74% |
| Sat Jul 24 | 7 h 35 min | 4 h 5 min | 1 h 36 min | 52 min | 64% |
| Sun Jul 25 | 7 h 37 min | 4 h 10 min | 1 h 58 min | 1 h 13 min | 54% |
| Mon Jul 26 | 7 h 40 min | 4 h 14 min | 2 h 25 min | 1 h 38 min | 44% |
| Tue Jul 27 | 7 h 43 min | 4 h 19 min | 2 h 59 min | 2 h 11 min | 33% |
| Wed Jul 28 | 7 h 45 min | 4 h 24 min | 3 h 44 min | 2 h 55 min | 23% |
| Thu Jul 29 | 7 h 48 min | 4 h 28 min | 4 h 44 min | 3 h 54 min | 14% |
| Fri Jul 30 | 7 h 51 min | 4 h 33 min | 5 h 59 min | 4 h | 7% |
| Sat Jul 31 | 7 h 54 min | 4 h 38 min | 7 h 24 min | 4 h | 2% |
Questions
- Can you see the northern lights in Tri-Cities in July?
- On dark, clear nights with enough activity. 31 of 31 nights at Tri-Cities have civil darkness, and 1% of past July days reached Kp 7.
- How dark is Tri-Cities in July?
- Tri-Cities averages 7.3 hours of civil night a night in July 2027, from 6 h 53 min on the 1st to 7 h 54 min on the last night.
- How cloudy is Tri-Cities in July?
- NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 26% mean cloud in July, against 56% for the whole year. It is an all-hours average, not a forecast.
- What is the best night in July 2027 for aurora in Tri-Cities?
- By darkness and moon alone, Jul 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Tri-Cities. Activity on that date will only be known hours ahead.
- Is July or August better in Tri-Cities?
- By civil night times the clear share, July scores 5.4 hours at Tri-Cities and August 6.2. August 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.