Cape Town sea temperature today
Cape Peninsula · False Bay · Overberg
Cape Town does not have one sea temperature. The Atlantic seaboard and False Bay are separate water bodies that regularly sit five degrees apart on the same afternoon, and which side you swim on matters more than which day you pick.
Sea temperature in Cape Town, today (Tuesday 1 September 2026): the water is 13.3 °C on the Atlantic seaboard and 14.8 °C on the Overberg coast — a difference of 1.6 °C between the two sides of the peninsula on the same day. That is cold water: 5–7 mm with a hood; gloves for anything over half an hour. Figures are modelled daylight-hour averages, not buoy measurements.
Cape Town sea temperature, today and the next two days
| Coast | Today 1 Sep | Tomorrow 2 Sep | Thursday 3 Sep | What to wear |
|---|---|---|---|---|
| Atlantic seaboard Atlantic swell, upwelling-driven |
13.3 °C | 13.3 °C | 12.4 °C | 5–7 mm with a hood; gloves for anything over half an hour. |
| False Bay False Bay western shore |
14.4 °C | 14.6 °C | 13.7 °C | 5–7 mm with a hood; gloves for anything over half an hour. |
| Overberg coast eastern side of False Bay |
14.8 °C | 14.8 °C | 14.2 °C | 5–7 mm with a hood; gloves for anything over half an hour. |
Modelled sea-surface temperature in °C, averaged over daylight hours. One representative site per coast: Atlantic seaboard, False Bay, Overberg coast.
Generated 2026-09-01 10:04 UTC. Updated every three hours.
Why the two coasts differ so much
The southeaster is the reason. On the Atlantic seaboard it blows offshore, pushing surface water away from the coast; that water is replaced from below by cold, nutrient-rich deep water. This is upwelling, and it can take the Atlantic side down several degrees within a day — the same mechanism that makes it some of the clearest water on the peninsula. The identical wind crosses the length of False Bay, arrives onshore on the western shore, and upwells nothing.
The practical consequence: the wind that makes the Atlantic seaboard cold and clear is the wind that makes False Bay warm and murky, and vice versa. On any given day one of the two is usually worth the drive.
Sea temperature in Cape Town by season
| Season | Atlantic seaboard | False Bay | What is happening |
|---|---|---|---|
| Summer (Dec–Feb) | 11–15 °C | 18–21 °C | Peak southeaster. The Atlantic side upwells hard and can drop below 10 °C overnight; False Bay is at its warmest. |
| Autumn (Mar–May) | 13–17 °C | 17–20 °C | The most settled diving of the year. The southeaster eases and both coasts converge. |
| Winter (Jun–Aug) | 13–16 °C | 14–17 °C | Northwesterly storm season. The two coasts sit closest together; the Atlantic is often the warmer of the two. |
| Spring (Sep–Nov) | 11–16 °C | 15–18 °C | The southeaster returns and the coasts diverge again. |
Indicative annual ranges, not forecasts. The table above this one carries the modelled figure for the next three days.
Common questions
How cold is the sea in Cape Town?
Cape Town has two seas, and they run several degrees apart. The Atlantic seaboard sits roughly 11–16 °C year round and drops sharply when the southeaster upwells cold water; the False Bay western shore runs roughly 14–21 °C and is warmest in late summer. The table on this page carries today’s modelled figure for each.
Why is the Atlantic side so much colder than False Bay?
The southeaster blows offshore on the Atlantic seaboard and pushes surface water away from the coast, which is replaced from below by cold deep water. That is upwelling, and it can take the Atlantic side down several degrees in a day. The same wind crosses the length of False Bay and arrives onshore, so it does not upwell there.
What wetsuit do I need in Cape Town?
For the Atlantic seaboard in summer, 7 mm with a hood, gloves and boots, or a drysuit. For False Bay in late summer a 5 mm full suit is usually enough. In winter the two coasts converge around 14–16 °C and a 5–7 mm hooded suit covers both.
When is the water warmest in Cape Town?
False Bay peaks in late summer, February and March, at around 18–21 °C. The Atlantic seaboard has no strong warm season: it is governed by upwelling rather than by air temperature, and is often at its warmest in winter when the southeaster is not blowing.
These are modelled sea-surface temperatures carried as context for theviz's water-clarity forecast, not readings from a buoy or a thermometer. Surface temperature is also not what you feel at depth: a thermocline can put the water eight degrees colder ten metres down. Dress for the colder number, and check locally before you get in.