🔎 TL;DR
- The Sea of Cortez runs two seasons that matter to divers: warm (Jul–Nov) with 27–29 °C water, peak visibility and pelagics, and cool (Jan–May) with 21–24 °C water, lower viz but the legendary winter pelagic rotation — gray and humpback whales, Cabo Pulmo bull sharks, La Paz whale sharks.
- Manta rays peak Aug–Nov off the cape; smaller-mouth (oceanic) mantas year-round, larger Pacific mantas concentrated in late summer / autumn.
- Bull sharks at Cabo Pulmo: Nov–Mar, peak Jan–Feb. Whale sharks La Paz: Oct–Apr, peak Dec–Feb. Humpback whales: Dec–Apr per CONANP survey data.
- Worst diving weeks: mid-Aug to mid-Oct hurricane risk per the National Hurricane Center. Cabo's storm history (Odile 2014, Norma 2023) means it's a real factor.
- The single best window for combining everything: late October–early November. Pre-norther, calm seas, warm water, mantas still here, humpbacks starting to arrive, no hurricane risk left.
Why Los Cabos divers care about season more than Caribbean divers
Cancún and Cozumel diving runs 12 months a year with relatively stable conditions — 26–29 °C all year, viz mostly above 20 m, and the only real variable is the sargassum bloom and hurricane risk. Los Cabos is fundamentally different. The southern Sea of Cortez is a high-latitude tropical sea — it sits between the Tropic of Cancer and the temperate Pacific — so it has a real seasonal cycle. Water temperature swings 8 °C between February and September. Pelagic species rotate in and out with currents. NOAA sea-surface temperature records show that the Cabo region warms steeply from May through August and cools steadily from November through February.
For divers, that means what you see depends heavily on when you go. A diver who comes in January and a diver who comes in September are diving the same coastline but seeing entirely different ecosystems. Below is the actual rotation, month by month, from data shared by Cabo San Lucas-based dive operators, validated against NOAA temperature data and CONANP marine-mammal survey reports.
The full month-by-month table
Visibility ranges are for cape sites (Pelican Rock, Land's End, North Wall). Cabo Pulmo viz tends to run 3–5 m higher most of the year. Water temperatures from NOAA sea-surface data for southern Gulf of California.
| Month | Water °C | Viz cape | Sea state | Marine life highlight | Hurricane risk |
|---|---|---|---|---|---|
| Jan | 21–22 | 10–20 m | Wind-affected | Bull sharks (Pulmo), humpbacks, gray whales | None |
| Feb | 21–22 | 10–20 m | Wind-affected | Bull sharks peak Pulmo, humpbacks, whale shark La Paz | None |
| Mar | 22–23 | 10–20 m | Improving | Last humpbacks, gray whales, whale shark La Paz | None |
| Apr | 23–24 | 15–25 m | Calm | End of winter pelagics, jacks return | None |
| May | 24–25 | 15–25 m | Calm | Marlin arriving, hammerheads possible | None |
| Jun | 25–27 | 15–25 m | Calm | Marlin, sailfish, schooling jacks | Low |
| Jul | 27–29 | 20–30 m | Calm | Peak warm season, eagle rays, marlin | Rising |
| Aug | 28–29 | 20–30 m | Storm watch | Mantas arriving, hammerheads occasional | Peak |
| Sep | 28–29 | 20–30 m | Storm watch | Mantas peak, mola mola occasional | Peak |
| Oct | 27–28 | 20–30 m | Improving | Mantas, whale shark La Paz starts | Declining |
| Nov | 25–26 | 20–30 m | Calm | Mantas late, bull sharks Pulmo start, humpbacks arriving | None |
| Dec | 22–24 | 15–25 m | Wind-affected | Gray whales arrive, humpbacks, bull sharks Pulmo | None |
Pick your window and let us build the trip around it. Book Los Cabos diving →
Winter (Dec–Mar) — the pelagic season nobody talks about
Most travel guides tell you to come to Cabo in winter for the beach weather. They're missing the real point. Winter is when the Sea of Cortez fills with charismatic mega-fauna: gray whales calving in Magdalena Bay on the Pacific side, humpbacks breeding between Cabo and the mainland, bull sharks aggregating at Cabo Pulmo, and whale sharks feeding in La Paz Bay. These four animal events overlap inside a 100 km radius.
The trade-off is conditions. Northers (El Norte) wind events blow Dec–Mar — north and northwest winds that kick up surface chop, reduce viz on exposed sites, and occasionally shut down boat operations for a day or two. Water drops to 21–23 °C, which is fine in a 5 mm wetsuit but feels cool if you're used to Caribbean water. Visibility on the cape sites drops to 10–20 m — still acceptable, just not the postcard 30 m of October.
What you can actually do in winter
- Bull-shark dive Cabo Pulmo — peak Jan–Feb, see our Cabo Pulmo guide.
- Whale shark snorkel La Paz — peak Dec–Feb, snorkel only by Mexican regulation.
- Humpback whale watching — peak Jan–Mar from boats around the cape.
- Regular dives at Pelican Rock and Sea Lion Colony continue — just check the wind forecast the day before.
Spring (Apr–May) — the underrated window
April and May are the calendar's secret. Water has warmed back to 23–25 °C, the northers have finished, hurricane season hasn't started, and most tourists haven't arrived. Visibility runs 15–25 m on the cape, marlin and sailfish are showing up, and the cape's resident schools of jacks are dense. The trade-off: the marquee winter pelagics (whale sharks, humpbacks, bull sharks) have left and the summer pelagics (mantas) haven't arrived. So you get good diving in great conditions without the once-a-year animal events.
This is the window we recommend for divers who want to combine cape diving with kitesurfing in nearby Los Barriles — the wind is dropping but still consistent through April, and the water is warm enough for long sessions. It's also a good window for first-time Cabo divers who want quality conditions without paying winter peak-season hotel rates.
Summer (Jun–Sep) — warm water, big animals, real hurricane risk
By July, water in Cabo hits 27 °C and keeps climbing. August and September are peak warmth (28–29 °C), with reef visibility 20–30 m and the most diverse marine-life calendar of the year: marlin, sailfish, eagle rays, hammerheads (occasional), the first mantas of the season starting in August. A 3 mm shorty is enough; some divers go in rash guards.
The problem is hurricanes. The eastern Pacific hurricane season runs May 15 – November 30 per NHC climatology, with peak activity August through early October. Cabo San Lucas sits at the apex of the Baja California peninsula, exposed to storms tracking up from the Pacific. The historical record is real: Hurricane Odile (2014) hit Cabo as a Category 3 and shut down the marina for weeks; Hurricane Norma (2023) made landfall as a Category 1 just west of Cabo. Most storms pass offshore, but the risk is non-zero.
If you book August–October, two things to factor in:
- Trip insurance with hurricane interruption coverage. The cape's airport closes routinely during direct hits.
- Flexible booking with the operator — we move dive days within your trip if a storm forces a day's closure.
Manta season — late summer to early winter
The most reliable big-animal encounter at the cape itself (not Cabo Pulmo, not La Paz) is the Pacific manta ray rotation, August through November. Two species cycle through:
- Mobula rays / smaller mantas — schools of 50–500 individuals can appear at Pelican Rock and North Wall, mostly Apr–Jul.
- Giant Pacific manta (Mobula birostris) — solo or pairs, wingspan 4–6 m, mostly Aug–Nov, occasionally deeper than 25 m.
Manta encounters at the cape are not guaranteed — they pass through more than they resident. Operators with weekly site reports usually know which week of August the first big mantas have shown up, and which sites they're cycling through. Reach out a couple of weeks before your trip and we'll tell you whether mantas are running.
The "best month" question — there isn't one, but if forced
Every dive operator and travel writer answers this differently. Our honest take, after running dive days year-round:
- Best overall conditions: late October to early November. Warm water, calm seas, late mantas, first humpbacks arriving, no hurricane risk, lower hotel rates than peak winter.
- Best for pelagic encounters: February. Bull sharks at Cabo Pulmo, whale sharks in La Paz, humpbacks everywhere — but cooler water and more wind-affected days.
- Best for first-time Cabo divers: April–May. Quality conditions, no extreme weather, easier to learn dive sites without rough seas.
- Best for combining with surface activities: November. Whale watching + diving + snorkelling all viable in the same trip.
- Avoid if you have no flexibility: mid-August to mid-September. Diving is excellent when it runs — but one named storm can shut your week.
Frequently asked questions
Can I dive Los Cabos year-round?
Yes. The cape is a year-round dive destination. Water never drops below 21 °C, dive operators run every month (except direct hurricane impact). What changes is what you see and how comfortable conditions feel. A 3 mm wetsuit is fine May–Oct; bump to 5 mm Nov–Apr.
What month has the best visibility?
July through November, with viz consistently 20–30 m on cape sites. December through April runs 10–20 m at the cape due to wind-driven surface chop and plankton blooms. Cabo Pulmo runs better viz year-round (less wind exposure inside the bay).
When can I see whale sharks?
Whale sharks aggregate in La Paz Bay (2 hours north of Cabo) from October through April, peak December through February. It is snorkel-only by Mexican regulation, regulated by CONANP. We can combine a La Paz whale-shark day with your Cabo dive trip.
Are humpback and gray whales the same season?
Overlapping but not identical. Humpbacks are in the Cabo / Sea of Cortez region December through April for breeding and calving. Gray whales arrive at Magdalena Bay on the Pacific side from mid-December through March for calving. Magdalena Bay is a 3-hour drive from Cabo — separate day trip.
Should I worry about hurricanes?
Realistically, if you book mid-August to mid-October, factor it in. Cabo gets direct or near-miss hurricane impact roughly once every 3–5 years (Odile 2014, Newton 2016, Norma 2023, plus smaller storms in between). Travel insurance with hurricane coverage is genuinely useful in this window. Outside Aug–Oct, hurricane risk is essentially zero.
Which week works best for what you want to see?
Tell us your dates and your target species — we will tell you honestly whether the timing lines up.