The Panama Canal's locks are filled by gravity from Gatun Lake, a freshwater reservoir fed by rain in the canal watershed. Every lockage lets fresh water from the lake run out to the sea. When the lake runs low, the ACP has two levers: cut the maximum draft (so ships need less water under the keel) and cut the number of daily transits. This guide explains the link, and where things stand.
The limits today
| Locks | Maximum authorized draft | Source |
|---|---|---|
| Neopanamax | 14.94 m (49.0 ft) tropical fresh water, since 28 September 2026 | A-36-2026 |
| Panamax | 12.04 m (39.5 ft) tropical fresh water | N-07-2026 |
The Neopanamax design draft is 15.24 m (50 ft). Drafts are measured in tropical fresh water (TFW), so a ship floats deeper in the canal than at sea. Check current figures on Panama status today.
Where the lake is now
In late October 2026 Gatun Lake stood at about 86.5 ft, close to the 2000–2025 median for the time of year (ACP daily readings, our calculation). The lake usually falls through the dry season (roughly January to April) and recovers in the rainy season. See the live chart.
The ACP also publishes a 60-day projection of the lake level and the maximum drafts it would expect to allow. In its late-October file it projects Neopanamax drafts of 50.0 ft through December. These projections are estimates for reference only. Official limits only change by Advisory to Shipping.
Why 2027 is the year to watch
The ACP has warned that a potentially severe El Niño could reduce water availability in the 2027 dry season, after rainfall across the watershed in May–August 2026 came in 34% below the historical average and inflows 44% below (A-29-2026). In the 2023–24 El Niño drought the lake fell to about 79 ft (July 2023, ACP data), and the ACP cut both drafts and daily transits: oceangoing transits averaged about 24 a day in December 2023, against about 33 through 2025 (ACP monthly summaries).
What that means for planning:
- Leave draft margin on voyages that transit from January to April 2027.
- Book early. When capacity is cut, unbooked waits grow fast.
- Consider LoTSA 2027 packages for fixed itineraries (competitions in November 2026). See booking slots and auctions.
How draft cuts are announced
The ACP announces draft changes by Advisory to Shipping, and has postponed planned cuts when conditions improved (A-33-2026 postponed a cut planned for 1 October 2026). Our Panama alerts cover each advisory, and the weekly brief sends them to your inbox.
Sources
- ACP Gatun Lake water level history and projection (evtms-rpts.pancanal.com)
- ACP Advisories to Shipping A-29-2026, A-33-2026, A-36-2026; Notice to Shipping N-01-2026, N-07-2026; Monthly Canal Operations Summaries: pancanal.com
Information only, not legal or operational advice. Confirm the draft limit for your transit date with the ACP or your agent.