Monthly Portstewart water temperature chart
The bar chart below shows the average monthly sea temperatures at Portstewart over the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| °C | 9.0 | 8.3 | 8.2 | 8.8 | 10.1 | 11.6 | 13.3 | 14.2 | 14.0 | 13.2 | 12.2 | 10.5 |
| °F | 48.2 | 46.9 | 46.8 | 47.8 | 50.2 | 52.9 | 55.9 | 57.6 | 57.2 | 55.8 | 54 | 50.9 |
Monthly average max / min water temperatures
The graph below shows the range of monthly water temperatures over several years.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min °C | 7.9 | 7.6 | 7.3 | 7.8 | 9.2 | 9.5 | 11.9 | 13 | 13.1 | 12.2 | 11.1 | 9.4 |
| Max °C | 10.1 | 9.1 | 9.2 | 9.9 | 11.1 | 13.8 | 14.8 | 15.5 | 14.9 | 14.2 | 13.3 | 11.7 |
| Min °F | 47.1 | 46.2 | 45.9 | 46.8 | 49.3 | 50.8 | 54.5 | 56.4 | 56.3 | 54.8 | 52.9 | 49.8 |
| Max °F | 49.3 | 47.7 | 47.8 | 48.9 | 51.2 | 55.1 | 57.4 | 58.9 | 58.1 | 56.8 | 55.1 | 52.1 |