Computed planning guide · Maui
Best Time to Snorkel in Maui: Month-by-Month Historical Conditions
This page compares the same 12-month historical model cohort across every month. It does not use generic travel prose or a seasonal rule of thumb: each row comes from stored HistoricalScoreMonth data.
Highest historical score
June 2026 · 29.2/100
Calmest modelled mornings
September 2025 · 39.3% calm from 6:00–11:00 local time
Coverage: 12/12 historical months · 1/12 with morning-calm data · 1 Sep 2025–31 Aug 2026.
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Maui snorkeling conditions by month
The morning column is the modelled share of valid local 6:00–11:00 hours meeting the calm-water rule. “Morning advantage” is morning calm minus the all-hours calm share, in percentage points. It is a descriptive comparison, not a safety rating.
| Month | Historical score | Morning calm | All-hours calm | Morning advantage | Mean SST | Coverage |
|---|---|---|---|---|---|---|
| September 2025 | 26.8/100 | 39.3% | 37.2% | 2.1 pp | 27.9°C82.1°F | 30 valid days720 sampled hours |
| October 2025 | 27.2/100 | Updating | 73.8% | Incomplete | 27.4°C81.3°F | 31 valid days744 sampled hours |
| November 2025 | 24.4/100 | Updating | 51.7% | Incomplete | 26.4°C79.5°F | 30 valid days720 sampled hours |
| December 2025 | 24.1/100 | Updating | 51.3% | Incomplete | 26.0°C78.8°F | 31 valid days744 sampled hours |
| January 2026 | 25.0/100 | Updating | 68.3% | Incomplete | 25.4°C77.8°F | 31 valid days744 sampled hours |
| February 2026 | 24.1/100 | Updating | 30.2% | Incomplete | 24.8°C76.7°F | 28 valid days672 sampled hours |
| March 2026 | 23.3/100 | Updating | 28.2% | Incomplete | 24.6°C76.3°F | 31 valid days744 sampled hours |
| April 2026 | 27.3/100 | Updating | 57.4% | Incomplete | 25.3°C77.5°F | 30 valid days720 sampled hours |
| May 2026 | 27.3/100 | Updating | 10.6% | Incomplete | 26.3°C79.4°F | 31 valid days744 sampled hours |
| June 2026 | 29.2/100 | Updating | 1.9% | Incomplete | 26.8°C80.2°F | 30 valid days720 sampled hours |
| July 2026 | 27.9/100 | Updating | 5.4% | Incomplete | 27.3°C81.2°F | 31 valid days744 sampled hours |
| August 2026 | 24.7/100 | Updating | 21.8% | Incomplete | 27.5°C81.6°F | 31 valid days744 sampled hours |
Methodology and limitations
- Source cohort: versioned
HistoricalScoreMonthrows only. Captured live forecasts are not substituted for missing historical months. - Historical Score: the stored monthly mean Snorkel Score, shown on a 0–100 scale. The month highlighted above is simply the highest stored monthly score in this window; no extra blended ranking formula is invented for this page.
- Morning calm: percent of valid local 6:00–11:00 hours with significant waves at or below 0.60 m and wind at or below 5.4 m/s. Missing morning data stays missing.
- All-hours calm: the same wave-and-wind rule across all valid hours in the month. A positive morning advantage means the stored mornings were calmer than the month overall.
- Water temperature: modelled monthly mean sea-surface temperature for the same historical cohort. See the linked climate page for the separate multi-year temperature baseline.
- Coverage: a stored historical month must meet the ranking system’s minimum valid-day threshold. Missing months render as incomplete rather than borrowing another year or repeating recent conditions.
- Limits: these are model estimates at a forecast grid point. They do not measure coral health, wildlife, water clarity, beach access, local closures or in-water safety. Conditions still vary by coast and by day.
Scoring profile: historical-v2-acb4a83d31a6feee · profile hash acb4a83d31a6feee.
Sources: Open-Meteo Marine API and ERA5 via the Historical Weather API.