Water temperature in Port Jefferson in July
Is it warm enough to swim in Port Jefferson in July? Average water temperature in Port Jefferson in July is 72.1°F and therefore suitable for comfortable swimming. The warmest sea in Port Jefferson in July is 77.7°F, and the coldest is 65.5°F. To find out the sea temperature today and in the coming days, go to Current sea temperature in Port Jefferson
Changes water temperature in Port Jefferson in July 2025, 2024
To get an accurate forecast for the water temperature in Port Jefferson for any chosen month, compare two years within a 10 year range using the chart below. In addition to the sea water temperature in Port Jefferson, the selected years in the table also show the values of the maximum and minimum temperatures on each of the days of July.
You can choose any other years:
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| July 1 | 71.8°F | 67.8°F | 66.9°F | 72.7°F |
| July 2 | 71.6°F | 67.5°F | 66.7°F | 71.8°F |
| July 3 | 72.1°F | 67.5°F | 66.2°F | 72.7°F |
| July 4 | 72.3°F | 68.2°F | 66.7°F | 73.8°F |
| July 5 | 71.6°F | 69.1°F | 66°F | 74.1°F |
| July 6 | 72.7°F | 69.4°F | 65.5°F | 74.8°F |
| July 7 | 72.5°F | 70.7°F | 66.6°F | 74.8°F |
| July 8 | 73.6°F | 70.2°F | 66.9°F | 74.3°F |
| July 9 | 74.1°F | 70.9°F | 67.8°F | 74.5°F |
| July 10 | 73.8°F | 72.7°F | 68.2°F | 74.7°F |
| July 11 | 72.9°F | 73°F | 68.4°F | 75°F |
| July 12 | 71.8°F | 73°F | 68.4°F | 75.2°F |
| July 13 | 71.8°F | 71.6°F | 68.2°F | 74.5°F |
| July 14 | 70.7°F | 72.7°F | 68.9°F | 74.5°F |
| July 15 | 71.4°F | 73.4°F | 68.5°F | 74.5°F |
| Day | 2025 | 2024 | Min | Max |
|---|---|---|---|---|
| July 16 | 72°F | 74.3°F | 68.9°F | 76.1°F |
| July 17 | 74.1°F | 74.5°F | 69.4°F | 77.2°F |
| July 18 | 75.2°F | 75.2°F | 70°F | 77.5°F |
| July 19 | 75.4°F | 75.7°F | 70.2°F | 77.7°F |
| July 20 | 75.4°F | 75.6°F | 70°F | 76.8°F |
| July 21 | 74.7°F | 74.7°F | 69.6°F | 76.5°F |
| July 22 | 74.1°F | 74.3°F | 69.8°F | 76.5°F |
| July 23 | 73°F | 74.1°F | 69.3°F | 77.2°F |
| July 24 | 73.6°F | 73.8°F | 69.1°F | 76.8°F |
| July 25 | 74.3°F | 71.2°F | 69.3°F | 77°F |
| July 26 | 74.7°F | 72.1°F | 70.2°F | 76.1°F |
| July 27 | 73.8°F | 70.9°F | 70.9°F | 77.2°F |
| July 28 | 75.4°F | 72.1°F | 70.5°F | 77.2°F |
| July 29 | 76.3°F | 71.1°F | 70.7°F | 77.7°F |
| July 30 | 76.1°F | 72°F | 70.9°F | 77.7°F |
| July 31 | 76.3°F | 73.4°F | 71.1°F | 77.5°F |
Average water temperature in Port Jefferson in July over a decade
| 2016 | 2017 | 2018 | 2019 | 2020 |
| 72.7°F | 72°F | 72.7°F | 73°F | 73.9°F |
| 2021 | 2022 | 2023 | 2024 | 2025 |
| 71.8°F | 72°F | 73.9°F | 72°F | 73.6°F |
Port Jefferson sea state in July
Chart comparing the height of waves in Port Jefferson in July 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.
Port Jefferson water temperature during other months:
You can also view information about water temperature for other months by clicking on the month button below
