Water temperature in Old Lyme (CT) in September

Is it warm enough to swim in Old Lyme in September? Average water temperature in Old Lyme in September is 69.3°F and therefore suitable for comfortable swimming. The warmest sea in Old Lyme in September is 75.6°F, and the coldest is 64.2°F. To find out the sea temperature today and in the coming days, go to Current sea temperature in Old Lyme

Changes water temperature in Old Lyme in September 2025, 2024

To get an accurate forecast for the water temperature in Old Lyme for any chosen month, compare two years within a 10 year range using the chart below. In addition to the sea water temperature in Old Lyme, the selected years in the table also show the values of the maximum and minimum temperatures on each of the days of September.

Average water temperature in Old Lyme in September over a decade

Chart comparing the height of waves in Old Lyme in September 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.

You can also view information about water temperature for other months by clicking on the month button below

The nearest locations with the average water temperature in September. In addition, the maximum and minimum water temperatures for that month, recorded over the last decade, are shown

If you have interesting photos of this place, you can upload them here. Photos will be available to all users after verification by the moderator.

Get widget or API for your website

Our report for Old Lyme is compiled using satellite data together with in-situ observations to get the most reliable daily data of sea surface temperatures, surf forecasts, current temperatures and weather forecasts.