Stargazing near Thunder Bay tonight

Thunder Bay sits inside Ontario's darkest region — Bortle 1–2 skies are reachable within an hour, and aurora is a near-monthly event.

Updated: · Tonight: Friday, August 14, 2026

Best dark-sky site near Thunder Bay tonight

★ Best tonight

Pukaskwa

Algoma, ON · Bortle 2 · 242 km away

Fair Short 3h window, otherwise mean cloud 61%. Worth a look if you're nearby.

Best clear window: Fri 5:00 p.m. – Fri 7:00 p.m. (3h, 1% mean cloud)

Moon: New moon · 2% illuminated

Open live forecast → Site guide

How we picked tonight's best site

Show ranking debug panel (4 candidates, 7-level tie-break)

Pukaskwa Lost on windowHours to Isle Royale (but earlier rule decided).

Site Verdict Window Win cloud Min cloud Mean cloud Bortle Distance
Isle Royale Fair (3) 2h 14% 1% 54% 2 49.6 km
Boundary Waters No-go (1) 0h — 84% 94% 1 141.5 km
Quetico No-go (1) 0h — 100% 100% 1 166.7 km
★ Pukaskwa Fair (3) 3h 1% 0% 61% 2 242.2 km

★ = chosen by tie-break ladder. Lower cloud %, lower Bortle, lower distance = better. Higher windowHours = better.

Tie-break ladder (in order)

  1. verdictRank (desc) — Excellent > Good > Fair > Poor > No-go
  2. windowHours (desc) — Longer clear window wins
  3. windowMeanCloudPct (asc) — Cleaner sky inside the window
  4. tonightMinCloudPct (asc) — Best moment of the night
  5. tonightMeanCloudPct (asc) — Overall sky quality
  6. bortle (asc) — Darker site wins
  7. distanceKm (asc) — Closer wins last

Same metrics are exposed at snapshot.json as bestTonight.tieBreak and closestSites[].tieBreak.

Understand tonight's forecast for Thunder Bay

Each verdict above blends four limiting factors. Tap a card to learn what it measures, where the number comes from, and how to use it.

📖 How to read the forecast Plain-English breakdown of every row, color and score. 🌙 Moon & tonight's window New moon · 2% illuminated ☁️ Cloud cover & sky score Mean cloud tonight: 61% (min 0%). 🔭 Transparency How clean the air column is — controls how faint a star you can see. 🔥 Smoke & AQI Wildfire smoke and PM2.5 from US-AQI — kills transparency before clouds do.

All 4 closest sites, ranked by distance

Isle Royale

Lake Superior, MI · Bortle 2 · 50 km away

Fair Short 2h window, otherwise mean cloud 54%. Worth a look if you're nearby.

Best clear window: Fri 6:00 p.m. – Fri 7:00 p.m. (2h, 14% mean cloud)

Moon: New moon · 2% illuminated

Open live forecast → Site guide

Pukaskwa

Algoma, ON · Bortle 2 · 242 km away

Fair Short 3h window, otherwise mean cloud 61%. Worth a look if you're nearby.

Best clear window: Fri 5:00 p.m. – Fri 7:00 p.m. (3h, 1% mean cloud)

Moon: New moon · 2% illuminated

Open live forecast → Site guide

Frequently asked questions

Where can I stargaze near Thunder Bay tonight?

Tonight's best site near Thunder Bay is Pukaskwa (242 km away). Verdict: Fair. Short 3h window, otherwise mean cloud 61%. Worth a look if you're nearby.

What is the closest dark-sky site to Thunder Bay?

Isle Royale is the closest, about 50 km from Thunder Bay (Bortle 2).

Can I see the Milky Way from Thunder Bay?

Thunder Bay's urban sky is too light-polluted for naked-eye Milky Way. For a clear view of the galactic band, drive to a Bortle 1–3 site such as Isle Royale, Boundary Waters, Quetico, Pukaskwa.

When are northern lights visible near Thunder Bay?

Aurora is visible during geomagnetic storms with Kp ≥ 5–6. Check the live aurora outlook and head to the closest dark site with a clean northern horizon.

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