Summit Lake Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Summit Lake Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Summit Lake Reservoir today is 18.5°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
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| OCT 5 | 20.5°C | 19.5°C | |
| OCT 6 | 20.2°C | 19.5°C | |
| OCT 7 | 19.7°C | 19.5°C | |
| OCT 8 | 18.9°C | 19.5°C | |
| OCT 9 | 19.1°C | 19.5°C | |
| OCT 10 | 18.6°C | 19.5°C | |
| OCT 11 | 18.1°C | 19.5°C | |
| OCT 12 | 18.6°C | 19.5°C | |
| OCT 13 | 19.5°C | 18.6°C | |
| OCT 14 | 19.5°C | 18.6°C | |
| OCT 15 | 19.5°C | 18.7°C | |
| OCT 16 | 19.5°C | 18.7°C | |
| OCT 17 | 19.5°C | 18.8°C | |
| OCT 18 | 19.5°C | 18.8°C | |
| OCT 19 | 19.5°C | 18.9°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.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 1°C | 6°C | 9°C |
| February | 1°C | 6°C | 10°C |
| March | 2°C | 6°C | 10°C |
| April | 6°C | 11°C | 16°C |
| May | 8°C | 14°C | 20°C |
| June | 16°C | 23°C | 30°C |
| July | 20°C | 24°C | 28°C |
| August | 23°C | 26°C | 29°C |
| September | 21°C | 25°C | 29°C |
| October | 17°C | 20°C | 22°C |
| November | 4°C | 11°C | 17°C |
| December | 2°C | 6°C | 9°C |
Summit Lake Reservoir: Water Temperature by Location
Summit Lake Reservoir: Weather Forecast
October 13
October 14
October 15
October 16
October 17
October 18
Location & Local Information
Summit Lake Reservoir, located in Summit Lake State Park in east‑central Indiana, experiences the typical seasonal swings of Midwestern lakes. In winter the surface often approaches freezing, roughly 32–40°F (0–4°C), and may develop ice depending on air temperatures. Spring sees a steady rise as runoff and warming air bring the surface into roughly 40–60°F (4–16°C). By mid‑ to late summer the shallow, sheltered water commonly warms to about 68–82°F (20–28°C), with occasional pockets reaching the upper 80s on heat‑wave days. In autumn the temperature falls again into the 50–65°F (10–18°C) range as cooling air and shorter days reduce surface warmth. Local factors such as recent rainfall, wind, and how deep you are in the lake can shift these values by several degrees.
Swimming is generally concentrated in the park’s designated beach area and is typically permitted during the warm season when the park opens the beach and staff or lifeguards are on duty; outside those posted times swimming may be at one’s own risk or restricted. Visitors should consider water temperature and conditions—colder shoulder‑season water can cause cold‑water shock, and summer conditions can bring wind or algae that affect safety—so following park signage and guidance is advisable before entering the water.