Water temperature in Half Moon Bay (CA) in May
Is it warm enough to swim in Half Moon Bay in May? Average water temperature in Half Moon Bay in May is 53.1°F and therefore is not suitable for comfortable swimming. The warmest sea in Half Moon Bay in May is 57.9°F, and the coldest is 47.7°F. Average high air temperature in Half Moon Bay in May is 62°F, and average low temperature is 47°F. To find out the sea temperature today and in the coming days, go to Current sea temperature in Half Moon Bay
Changes water temperature in Half Moon Bay in May 2025, 2024
To get an accurate forecast for the water temperature in Half Moon Bay for any chosen month, compare two years within a 10 year range using the chart below. In addition to the sea water temperature in Half Moon Bay, the selected years in the table also show the values of the maximum and minimum temperatures on each of the days of May.
You can choose any other years:
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| May 1 | 52.9°F | 49.8°F | 49.1°F | 55.6°F |
| May 2 | 53.2°F | 49.6°F | 48.9°F | 56.1°F |
| May 3 | 53.2°F | 50.7°F | 49.6°F | 56.7°F |
| May 4 | 51.4°F | 51.4°F | 48.6°F | 56.5°F |
| May 5 | 51.8°F | 51.4°F | 49.3°F | 56.5°F |
| May 6 | 52.5°F | 50.7°F | 49.8°F | 56.3°F |
| May 7 | 52.5°F | 50.9°F | 49.8°F | 55.8°F |
| May 8 | 52.7°F | 50.4°F | 49.3°F | 55.4°F |
| May 9 | 54°F | 49.5°F | 49.3°F | 55.2°F |
| May 10 | 54.5°F | 52°F | 49.6°F | 55.2°F |
| May 11 | 54.9°F | 53.1°F | 49.5°F | 57.4°F |
| May 12 | 55°F | 53.6°F | 49.8°F | 57°F |
| May 13 | 54.3°F | 53.8°F | 50°F | 56.8°F |
| May 14 | 54.1°F | 54°F | 49.3°F | 56.8°F |
| May 15 | 54.5°F | 54.1°F | 47.7°F | 56.7°F |
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| May 16 | 54.5°F | 54.7°F | 48.4°F | 56.8°F |
| May 17 | 54°F | 54°F | 50°F | 57°F |
| May 18 | 52.5°F | 54°F | 50.4°F | 57.6°F |
| May 19 | 51.1°F | 54.9°F | 49.6°F | 57.7°F |
| May 20 | 51.1°F | 56.1°F | 49.6°F | 57.9°F |
| May 21 | 51.3°F | 56.5°F | 49.8°F | 56.8°F |
| May 22 | 50.5°F | 54.9°F | 50°F | 56.5°F |
| May 23 | 51.1°F | 53.8°F | 49.6°F | 57°F |
| May 24 | 51.6°F | 52.9°F | 49.8°F | 57°F |
| May 25 | 52.2°F | 52.9°F | 50.4°F | 57°F |
| May 26 | 52.9°F | 53.6°F | 48.9°F | 56.3°F |
| May 27 | 53.1°F | 55.4°F | 49.8°F | 56.3°F |
| May 28 | 54°F | 53.6°F | 49.8°F | 56.1°F |
| May 29 | 54.5°F | 53.4°F | 51.1°F | 56.1°F |
| May 30 | 54.5°F | 52.5°F | 51.1°F | 55.9°F |
| May 31 | 54.1°F | 52.3°F | 50.5°F | 55.9°F |
Average water temperature in Half Moon Bay in May over a decade
| 2016 | 2017 | 2018 | 2019 | 2020 |
| 55.4°F | 53.2°F | 54.5°F | 56.3°F | 54.5°F |
| 2021 | 2022 | 2023 | 2024 | 2025 |
| 51.4°F | 50.2°F | 54°F | 52.9°F | 53.1°F |
Half Moon Bay sea state in May
Chart comparing the height of waves in Half Moon Bay in May over the past years. The red line indicates the height of the waves when swimming in the sea is prohibited. To view the current sea conditions, click on the graph.
Weather and climate in Half Moon Bay in May
This data display average monthly climate indicators in Half Moon Bay in May based on our historical weather readings over a period of ten years. In addition to temperature, we include data on the number of rainy and sunny days so you can have all the information about your destination before your trip
- Average HIGH temperature62°F
- Average LOW temperature47°F
- Average rainfall days5 days
- Average rainfall20mm/0.8''
Half Moon Bay water temperature during other months:
You can also view information about water temperature for other months by clicking on the month button below
