Experienced divers only
Is it worth the trip?
49Fair out of 100 for your dates
Best on Tue 3: Sea 0.6 m, Water 9 °C, Wind 6 kn
Tue 3 · 61 out of 100
- Sea
- 0.6 m
- Wind
- 6 kn
- Gusts
- 9kn
- Air
- 9°C
Wed 4 · 54 out of 100
- Sea
- 1.2 m
- Wind
- 6 kn
- Gusts
- 7kn
- Air
- 11°C
Thu 5 · 50 out of 100
- Sea
- 1.5 m
- Wind
- 15 kn
- Gusts
- 20knboats in
- Air
- 10°C
Fri 6 · 38 out of 100
- Sea
- 2.0 m
- Wind
- 13 kn
- Gusts
- 20kn
- Air
- 10°C
Sat 7 · 49 out of 100
- Sea
- 1.2 m
- Wind
- 15 kn
- Gusts
- 32knboats in
- Air
- 8°C
Sun 8 · 49 out of 100
- Sea
- 1.2 m
- Wind
- 15 kn
- Gusts
- 25knboats in
- Air
- 10°C
Mon 9 · 20 out of 100
- Sea
- 1.6 m
- Wind
- 24 kn
- Gusts
- 32knboats in
- Air
- 9°C
Tap a day for sea, wind and water. Full forecast
Forecast: next 9 days
Full forecast- Tue 361, good
- Wed 454, fair
- Thu 550, fair
- Fri 638, poor
- Sat 749, fair
- Sun 849, fair
- Mon 920, poor
- Tue 1059, fair
- Wed 1147, fair
The site in five facts
- Down to 25 mits deepest
- From a boathow you get in
- Experienced / deepexperienced divers only
- Water 9 °Cdrysuit
- Faces NEswell from there reaches it
Full forecast
every day, every number
The score doesn't know currents, the visibility on the day or your certification.
Suits experienced divers only, as a dive guide states it. Scored for experienced divers.
| Day | Score | Sea | Wind | Gusts | Air |
|---|---|---|---|---|---|
| Tue 3Nov | 61, good | 0.6 m | 6 kn | 9kn | 9°C |
| Wed 4Nov | 54, fair | 1.2 m | 6 kn | 7kn | 11°C |
| Thu 5Nov | 50, fair | 1.5 m | 15 kn | 20knboats in | 10°C |
| Fri 6Nov | 38, poor | 2.0 m | 13 kn | 20kn | 10°C |
| Sat 7Nov | 49, fair | 1.2 m | 15 kn | 32knboats in | 8°C |
| Sun 8Nov | 49, fair | 1.2 m | 15 kn | 25knboats in | 10°C |
| Mon 9Nov | 20, poor | 1.6 m | 24 kn | 32knboats in | 9°C |
| Tue 10Nov | 59, fair | 1.0 m | 10 kn | 15kn | 8°C |
| Wed 11Nov | 47, fair | 1.0 m | 22 kn | 28knboats in | 10°C |
Sea is the waves near the site, in metres; wind and gusts in knots. "Boats in": gusts that keep dive boats in. More
Tide
- Tue 3 NovLow 00:54 −1.6 mHigh 07:40 +1.2 mLow 13:44 −0.9 mHigh 19:40 +1.0 m
- Wed 4 NovLow 02:00 −1.5 mHigh 08:34 +1.4 mLow 14:51 −1.3 mHigh 20:55 +1.1 m
- Thu 5 NovLow 02:57 −1.4 mHigh 09:20 +1.6 mLow 15:45 −1.6 mHigh 21:56 +1.2 m
Local clock times; heights about mean sea level. On open coasts the times are usually within a quarter of an hour; in bays, estuaries and on the Gulf of Mexico they can be an hour or more out. Slack water, the safest time to dive where there is current, is about half an hour either side of each high and low. Tide: EOT20 global ocean tide model, Hart-Davis et al. 2021, DGFI-TUM (doi:10.17882/79489), CC BY 4.0. Times and heights computed by us. A model, not a tide table: check a local table before you go.
Forecast updated . It refreshes every three hours. Forecast data: ECMWF, DWD, Météo-France and NOAA, served by Open-Meteo.com (CC BY 4.0). Changed by us. Generated using E.U. Copernicus Marine Service Information.
Best time to go
No month stands out
Good diving days in a typical week, each month, for experienced divers, from 2016 on (ERA5 history scored the same way).
- Jan6of 7: a trip from Sat 2 Jan
- Feb6of 7: a trip from Sat 6 Feb
- Mar7of 7: a trip from Sat 6 Mar
- Apr7of 7: a trip from Sat 3 Apr
- May7of 7: a trip from Sat 1 May
- Jun7of 7: a trip from Sat 5 Jun
- Jul7of 7: a trip from Sat 3 Jul
- Aug7of 7: a trip from Sat 7 Aug
- Sep7of 7: a trip from Sat 4 Sept
- Oct6of 7: a trip from Sat 2 Oct
- Nov6of 7: a trip from Wed 4 Nov
- Dec5of 7: a trip from Sat 5 Dec
Tap a month to see this spot for a trip then.
Typical, not a forecast: the sea and the mean wind of each day, with no gusts or rain in the history.
Map
the site and its town
Alert Rock on Google Maps · Directions
Each place wears its best day on these dates: green good, amber fair, pale red poor, as the key says.
The map needs JavaScript. Every place on it is listed on this page, and each place's page links to Google Maps.
One finger scrolls the page; two fingers move the map. Pins are our own positions. Map OpenFreeMap, © OpenMapTiles, data © OpenStreetMap contributors.
About
the place in full, sources, credits
About Alert Rock
A reef dive. It goes down to 25 m. You get in from a boat. It suits experienced divers only, as a dive guide states it. The coast faces NE: swell from the NE reaches it, and wind from the SW blows out to sea. No dive centre within 50 km on the map: book a liveaboard or a boat from further off. The sea is about 7°C in February, its coldest month (drysuit), and 13°C in July, its warmest (7 mm semi-dry or a drysuit). No town nearby. Nearest place to stay we found: Langara Fishing Lodge, Area D (Graham Island), 2 km. Nearest beds: Masset, 57 km. Nearest airport: Masset Airport (ZMT), 58 km. Within 5 km we also list 1 surf spot and 5 dive sites.
- What it is Reef.
- How deep Down to 25 m.
- Getting in From a boat.
- Who it suits Suits experienced divers only, as a dive guide states it.
- Dive centres No dive centre within 50 km on the map: book a liveaboard or a boat from further off.
Water about 9°C: drysuit. Typical sea temperature for the time of year, not a forecast.
The score is the conditions only: the journey, the price and the partners never change it (how we score, how we earn).
Where to stay: nearest beds 57 km away
Ad Links marked Ad may pay us if you book. You pay the same, and they never change a score. How we earn
No town nearby
Nearest place to stay we found: Langara Fishing Lodge, Area D (Graham Island), 2 km. Nearest beds: Masset, 57 km. Nearest airport: Masset Airport (ZMT), 58 km.
See places to stay near Masset, 57 km away · Booking.comDistances are straight lines: a site out at sea is reached by boat.
Getting there
eSIM for your phone · Search on AiraloAd
An estimate, one way; the journey never changes the score.
In the water
Dives and courses in Alert Rock · GetYourGuideDive gear hire in Alert Rock · GetYourGuide
Dive centres nearby
No dive centre mapped within 50 km.
Dive centres: © OpenStreetMap contributors (ODbL). Credits
What you might see
Too few records at this site itself, so these are the animals divers and surveys have recorded at other sites within 25 km in the last 15 years. A record says someone saw it there, not that you will.
Harbor seal Phoca vitulinaSeal or sea lion
Seen in 3 records.
Records: OBIS (Ocean Biodiversity Information System, IOC-UNESCO) and GBIF.org (1 November 2026, doi:10.15468/dl.jeesns), from the datasets named here, CC0 and CC BY records only. Names: WoRMS and GBIF; common names from the Catalogue of Life, the GBIF Backbone and Wikidata. Largest datasets here: Hard Bottom Longline Hook Survey - Outside North; iNaturalist Research-grade Observations; Happywhale - Humpback whale in North Pacific Ocean. Credits
What is under the water this week (visibility, current) no free forecast gives. Ask a dive centre before you book.
Saved: this link opens the same trip
The link holds the trip itself: nothing about you is kept. Check the forecast again before you book.