Can you go through the Ballard Locks at night?

Yes. The locks run 24 hours a day, year-round, on demand, with no timetable and no fee. Attendants are on duty overnight and VHF channel 13 is staffed 24 hours. Night lockages are routine, not an exception.

Are the Ballard Locks quieter after dark?

Substantially. Measured across 1,176 lockages over the 30 days from 30 July to 28 August 2026: recreational traffic runs about 1.7-1.9 lockages per hour through the afternoon, falls to about 0.8 per hour in the two hours after sunset, and to about 0.1 per hour beyond that. Comparing two hours either side of sunset that is 48% of the pre-sunset rate; comparing three hours either side it is 34%. The figure depends on the window, so quote it with one.

Is the wait shorter at night at the Ballard Locks?

Yes, and it is the shortest measured. Note these are transit times — arrival to clearing the chamber, including the lockage itself — not queue time alone. The median recreational transit in the one to three hours after sunset was 17 minutes, against 28 minutes in the late afternoon. The sample is small (26 lockages) so treat it as indicative. The catch is that the improvement arrives before the traffic thins: the median is already down to 20 minutes in the two hours BEFORE sunset, while recreational traffic is still at full daytime rate.

Does the evening quiet at the locks shift with sunset through the year?

Unknown, and worth being honest about. Over the 30 days measured, sunset moved 51 minutes earlier, and indexing the evening drop on clock hour fitted slightly better than indexing it on time-relative-to-sunset. That hints boaters go home on a domestic schedule rather than by the light, but 51 minutes of drift across one month is not enough to separate two variables that closely related. A winter archive, where Seattle sunset falls around 16:20 against 20:48 in late July, would settle it.

The Ballard Locks after dark

Q: Why does the transit time improve in the evening at the Ballard Locks?

Commercial traffic stops, not recreational traffic. Commercial lockages fall from about 0.77 per hour in the late afternoon to 0.34, then 0.21 after sunset, and on 16 of the 30 days measured the last commercial lockage of the day happened before sunset. Because commercial vessels take the small lock to themselves and hold federal priority under 33 CFR 207.750, their departure relieves the queue while pleasure boats are still arriving at full rate.

Last updated 2026-08-29 · measured across 1,176 lockages over the 30 days from 30 July to 28 August 2026, from US Army Corps of Engineers records

The locks run all night. Twenty-four hours a day, year round, on demand, no timetable and no fee — attendants are on duty and VHF channel 13 is staffed through the night. A two in the morning lockage is routine.

The obvious question is whether it is worth waiting for. The answer is yes, but the reason is not the one most boaters give, and getting the reason right changes when you should actually leave.

Traffic collapses after sunset

A note on the numbers. Every figure on this site is transit time: from the moment you arrive off the guide piers to the moment you clear the chamber. It is not queue time alone — the lockage itself is inside it, and through the afternoon that runs about 18 minutes. So a 42-minute figure means 42 minutes door to door, roughly 24 of them waiting; it does not mean 42 minutes of waiting and then a lockage on top.

Recreational traffic runs remarkably flat through the day and then falls off a cliff. Indexed to sunset, which is the fair way to compare across a month in which sunset moved 51 minutes earlier:

Lockages per hour and median recreational transit time (arrival to clear), by time relative to sunset. 1,176 lockages, 30 July – 28 August 2026 (30 days).
Relative to sunset	Commercial /hr	Recreational /hr	Median transit
6–4 hours before	0.77	1.40	28 min
4–2 hours before	0.32	1.87	25 min
2–0 hours before	0.34	1.73	20 min
0–2 hours after	0.21	0.82	21 min
2–5 hours after	0.09	0.09	18 min

Comparing the two hours before sunset with the two hours after, recreational traffic falls to 48% of its pre-sunset rate; widen both sides to three hours and it falls to 34%. The figure depends on the window, so it is quoted here with one. Traffic is near nil, and to almost nothing after that. In the one to three hours past sunset the median transit was 17 minutes — the lowest median anywhere in the archive, against 28 minutes in the late afternoon. That sample is 26 lockages, so treat it as indicative rather than precise.

The chamber itself gets faster

This was not expected. Splitting transit into its two parts — the queue, and the lockage itself — shows the chamber speeding up after dark:

Relative to sunset	Queue	Chamber	Transit
6–2 hours before	5 min	18 min	25 min
2–0 hours before	5 min	15 min	20 min
0–1 hours after	6 min	14 min	23 min
1–3 hours after	4 min	13 min	17 min

Eighteen minutes in the afternoon, thirteen after dark — five minutes off the part of the transit that is usually described, including on this site until we checked, as the irreducible bit. It is not irreducible. It is just busier during the day.

The obvious explanation is one we cannot test. A chamber holding two boats should load, tie off and empty faster than one holding five, and there are far fewer boats about at night — so fewer boats per lockage is the natural reading. But the Corps logs recreational traffic as anonymous grouped records with no vessel count, so the number of boats in any given chamber is not in the data. The speed-up is measured; the cause is a hypothesis, and we are not going to state it as more than that.

But the improvement arrives before the boats leave

Look at the third row of that table again. The median transit is already down to 20 minutes in the two hours before sunset — while recreational traffic is still running at 1.73 lockages an hour, essentially its full daytime rate.

The transit time improves before the crowd goes home. So the crowd going home is not what improves it.

What actually changes at dusk is the commercial fleet. Commercial lockages fall from 0.77 an hour in the late afternoon to 0.34, then to 0.21 after sunset. On 16 of the 30 days measured the last commercial lockage of the day happened before sunset. Because commercial vessels take the small lock to themselves and hold federal priority under 33 CFR 207.750, one ahead of you costs a full cycle — so when the tugs and tour boats knock off, the queue relaxes while pleasure boats are still arriving at full rate.

This is the same pattern that runs through everything else measured here. Recreational arrivals are nearly constant through daylight — hour-to-hour variation of only about 14%, against more than 60% for commercial. You are almost never dodging other pleasure boats. You are dodging commercial vessels, and the cycle luck they create.

The practical consequence: you do not have to wait for dark. Most of the evening gain is available in the last couple of hours of daylight, once the commercial day has wound down. Waiting a further two hours for full dark buys perhaps three more minutes, at the cost of handling lines in the dark.

Does the evening quiet move with sunset through the year?

This matters more than it sounds. Seattle sunset falls around 20:48 in late July and around 16:20 in December. If the evening lull is driven by darkness, it arrives at half past four in winter. If it is driven by the clock — dinner, bedtime, work in the morning — it stays put at nine in the evening all year, and a boater planning a December passage from summer figures would be four hours wrong.

The archive contains a small natural experiment: sunset moved 51 minutes earlier across the month measured. Splitting the month in half, normalising for a 4% seasonal decline in overall traffic, and asking which index makes the two halves agree:

Indexed on clock hour — disagreement 0.052
Indexed on time relative to sunset — disagreement 0.066

Clock hour fits better, by about 21%. That points toward boaters going home on a domestic schedule rather than by the light.

We are not claiming this. Fifty-one minutes of drift across 30 days is not enough to separate two variables that closely related, and the gap between the two fits is small enough to be noise. What the data supports is: the evening drop is real and large, and there is currently no evidence it tracks sunset rather than the clock. A winter archive settles it — a 4.5-hour swing in sunset cannot be confused with anything — and we will publish the answer when there is one, whichever way it falls.

What is worth knowing if you do lock through at night

Both parts of the transit improve, but unevenly. The queue is where most of the gain is; the chamber itself also speeds up, from a median 18 minutes in the afternoon to about 13 after dark (see above — the cause is a hypothesis, not a measurement). What does not move is the floor: nothing in 1,176 records cleared in under 10 minutes, at any hour.
Bridge openings change character. Between 11 pm and 7 am, Ship Canal bridge openings require an hour's advance notice (33 CFR 117.1051) — a masted vessel that locks through at midnight can find itself held below the Ballard Bridge. Powerboats are unaffected.
Lighting and line handling are the real cost. The walls, the cleats and the other boats are all harder to read in the dark, and rafting to a stranger is harder still.
Our shore camera does not see at night, so the vessel counts behind the live forecast are daylight-only. Night figures on this page come entirely from Corps lockage records, which are logged around the clock.

The honest limit on all of this

One month is one month, and it is a high-summer month. Every figure here describes 30 July to 28 August 2026. August evenings are warm and light until nearly nine; November evenings are neither, and the traffic behaves differently for reasons that have nothing to do with lock operations. Nothing on this page should be read as a year-round claim, and where a sample is small it is stated so you can judge it yourself.

These are measured figures for the window stated, not a live reading. Current conditions — including how tonight is actually running — are on the live forecast.

Common questions

Can you go through the Ballard Locks at night?: Yes. Twenty-four hours a day, year round, on demand, with no timetable and no fee. Attendants are on duty overnight and VHF channel 13 is staffed 24 hours.
Are the Ballard Locks quieter after dark?: Substantially. Recreational traffic falls from about 1.7–1.9 lockages an hour through the afternoon to about 0.8 in the two hours after sunset, and about 0.1 beyond that — 48% of the pre-sunset rate comparing two hours either side of sunset, 34% comparing three. Beyond that, almost nothing.
Is the wait shorter at night?: Yes, and it is the shortest measured: a median transit of 17 minutes in the one to three hours after sunset, against 28 in the late afternoon (n=26, so indicative). But most of that gain is already available before sunset.
Why does the evening transit time improve?: Commercial traffic stops, not recreational traffic. On 16 of the 30 days measured the last commercial lockage happened before sunset, and commercial vessels take the small lock alone under federal priority — so their departure relieves the queue while pleasure boats are still arriving at full rate.
Does the evening lull shift earlier in winter?: Unknown. Clock hour fitted the evening drop slightly better than sunset time over the month measured, hinting the lull is schedule-driven rather than light-driven, but one month of summer cannot settle it. A winter archive will.