Last updated ·
Today, September 13, the sea temperature at Mirissa is 29.2 °C (85 °F). That is 0.7 °C warmer than the usual 28.5 °C in September. Comfortable for swimming year-round.
Warmest in April (30.1°C). Coldest in August (27.9°C). Comfortable for swimming year-round.
| Month | Sea · Min | Sea · Avg | Sea · Max | Air · Min | Air · Avg | Air · Max |
|---|---|---|---|---|---|---|
| January | 27.9°C | 28.3°C | 28.6°C | 24.2°C | 26.2°C | 28.9°C |
| February | 28.2°C | 28.6°C | 28.9°C | 24.5°C | 27.0°C | 30.4°C |
| March | 29.0°C | 29.3°C | 29.6°C | 25.0°C | 27.2°C | 30.1°C |
| April | 29.8°C | 30.1°C | 30.5°C | 25.6°C | 27.5°C | 30.1°C |
| May | 28.9°C | 29.4°C | 29.9°C | 26.3°C | 27.6°C | 29.4°C |
| June | 28.3°C | 28.7°C | 29.1°C | 25.9°C | 27.3°C | 29.1°C |
| July | 27.4°C | 28.0°C | 28.6°C | 25.9°C | 27.1°C | 28.9°C |
| August | 26.9°C | 27.9°C | 28.9°C | 25.5°C | 26.9°C | 28.7°C |
| September | 27.8°C | 28.5°C | 29.1°C | 25.5°C | 26.8°C | 28.7°C |
| October | 28.4°C | 28.9°C | 29.2°C | 25.1°C | 26.5°C | 28.4°C |
| November | 29.0°C | 29.4°C | 29.8°C | 24.8°C | 26.4°C | 28.6°C |
| December | 28.1°C | 28.7°C | 29.2°C | 24.6°C | 26.5°C | 28.9°C |
Sri Lanka's south coast turns Mirissa into one of the world's most reliable blue-whale viewpoints, with dawn boats from the harbour intercepting the Indian Ocean shipping lane between November and April. Mirissa Beach curves for a kilometre of fine sand backed by coconut palms, anchored by the tide-washed islet of Parrot Rock, while three kilometres west Weligama Beach runs flatter and broader as the island's surf-school capital. Sea temperatures hold 27–28 °C81–82 °F year-round.
Today, September 13, the sea at Mirissa is 29.2 °C (85 °F)85 °F (29.2 °C) – bathtub-warm. The usual September average is 28.5 °C83 °F.
No single number works for everyone, so the scale on this page is only a guide to how the water feels: below 13 °C55 °F icy, 13–18 °C55–64 °F cold, 18–23 °C64–73 °F refreshing, 23–28 °C73–82 °F pleasantly warm and above 28 °C82 °F like a bath. Right now the sea at Mirissa is 29.2 °C85 °F.
Yes – the sea at Mirissa (Indian Ocean, Sri Lanka) stays swimmable all year. August is the coolest month, averaging 27.9 °C82 °F – ideal for swimming for most people; the warmest is April at 30.1 °C86 °F.
In April, at 30.1 °C86 °F on average. The coolest month is August at 27.9 °C82 °F – still above the 18 °C64 °F swimming line, so there is no off-season for swimming.