Harpswell — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for Harpswell (Maine, United States). It includes the current water temperature, daily data for the last month presented in a simple chart, and a 7-day forecast. The page also compares today’s value with typical averages for this period, shows usual monthly ranges during the year, and lists nearby beaches with short descriptions. Local weather for the next few days and general details about Harpswell help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in Harpswell in the Atlantic Ocean today is 18°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming.
It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Water temperature in Harpswell rose over the last 30 days but fell over the last week. Currently, the sea water temperature at this location matches the average for this day in previous years.
According to our forecast, Water temperature in Harpswell will be 17.2°C in the next 7 days. See the table below for daily data for the upcoming week.
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| AUG 9 | 18.5°C | 17.5°C | |
| AUG 10 | 19.1°C | 18.5°C | |
| AUG 11 | 19.7°C | 18.5°C | |
| AUG 12 | 19.9°C | 18.0°C | |
| AUG 13 | 19.9°C | 18.8°C | |
| AUG 14 | 19.4°C | 18.5°C | |
| AUG 15 | 19.5°C | 19.3°C | |
| AUG 16 | 18.8°C | 19.0°C | |
| AUG 17 | 17.7°C | 18.5°C | 17.7°C |
| AUG 18 | 18.3°C | 17.6°C | |
| AUG 19 | 18.0°C | 17.6°C | |
| AUG 20 | 17.8°C | 17.5°C | |
| AUG 21 | 17.8°C | 17.4°C | |
| AUG 22 | 17.8°C | 17.4°C | |
| AUG 23 | 17.8°C | 17.3°C | |
| AUG 24 | 17.5°C | 17.2°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Water temperature data for this location is gathered from various sources, including buoys and satellite sea and ocean surface maps provided by the NOAA agency. We also incorporate data from local authorities in each specific location worldwide to ensure more accurate temperature readings.
Annual Water Temperature Overview by Month
Monthly Water Temp Ranges
Annual Water Temperature Trend
Harpswell is a coastal town on Maine’s rugged Gulf of Maine shoreline, characterized by a mix of rocky ledges, islands, and small sandy coves. Water temperatures reflect the cool North Atlantic influence and strong tidal flows: in winter the sea near Harpswell typically ranges from about 0 °C to 4 °C, remaining near freezing in shallow areas; spring sees a gradual rise from roughly 2 °C in early spring to around 8–10 °C by late May; summer brings the warmest conditions, with surface temperatures commonly between 12 °C and 18 °C in July and August, though shallow, sheltered coves can be a few degrees warmer on hot days; autumn cooling starts in September with waters generally falling from about 14 °C down through October into the single digits by late fall.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 2°C | 5°C | 9°C |
| February | 1°C | 3°C | 6°C |
| March | 1°C | 4°C | 6°C |
| April | 2°C | 5°C | 8°C |
| May | 4°C | 8°C | 13°C |
| June | 8°C | 13°C | 16°C |
| July | 12°C | 16°C | 20°C |
| August | 13°C | 18°C | 21°C |
| September | 12°C | 16°C | 19°C |
| October | 8°C | 14°C | 17°C |
| November | 7°C | 11°C | 13°C |
| December | 3°C | 8°C | 11°C |
* Click on a month to view detailed water temperature data.
Harpswell: Weather Forecast
August 18
August 19
August 20
August 21
Location, Beaches & Local Information
Nearby Beaches & Facilities
Littlejohn
Swimming Conditions
Swimming and beach holidays in Harpswell are best planned for the brief warm season when conditions are most comfortable. Mid-July through early September offers the most reliable window for open-water swimming, yet even then many visitors find the water brisk and opt for short dips, neoprene layers, or wetsuits for longer swims. Sandier coves and sheltered inlets provide calmer water and easier entry, while exposed rocky shores offer scenic but colder and more abrupt conditions. Tidal currents and variable bottom contours mean swimmers should be cautious, check local tide information, and use buddy systems; lifeguards are uncommon, so beachgoers often favor family-friendly coves or use kayaks and paddleboards to explore warmer, protected waters. Overall, Harpswell is appealing for a coastal holiday where swimming is a refreshing activity rather than a warm-water beach experience.