Grassholme Reservoir — Current Water Temperature, Annual Trends and Forecast

This page provides information on the current water temperature in Grassholme Reservoir, trends, monthly ranges and the forecast for the coming days.

Cow Green Reservoir, United Kingdom © By Paul White, CC BY-SA 4.0

Current Water Temperature

12.6°C

Today

12.7°C

Yesterday

13.3°C

A Week Ago

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Water Temperature in Grassholme Reservoir today is 12.6°C.

Water Temperature: Daily Trends, Historical Records, and Forecast

⚠️ As of today, the minimum water temperature ranges from 54°F (12°C) to 60°F (15°C). The water is significantly warmer, and swimming becomes possible for most people. However, caution may still be required for prolonged stays in the water, as extended exposure can cause discomfort. This is a suitable temperature range for short swims and for those accustomed to cooler water. For more comfortable swimming, it is recommended to use proper gear. 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

From May 10 to June 10

Table of Daily Sea Temperature Data

Date	Current	Average	Forecast
JUN 3	12.2°C	18.6°C
JUN 4	12.2°C	18.6°C
JUN 5	12.2°C	18.6°C
JUN 6	12.2°C	18.6°C
JUN 7	12.7°C	18.6°C
JUN 8	12.7°C	18.6°C
JUN 10	12.6°C	18.6°C
JUN 11		18.6°C	12.9°C
JUN 12		18.6°C	13.2°C
JUN 13		18.6°C	13.5°C
JUN 14		18.6°C	13.8°C
JUN 15		18.6°C	14.1°C
JUN 16		18.6°C	14.4°C
JUN 17		18.6°C	14.7°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	0°C	4°C	7°C
February	0°C	4°C	7°C
March	2°C	6°C	9°C
April	5°C	9°C	12°C
May	9°C	14°C	20°C
June	12°C	19°C	25°C
July	16°C	21°C	26°C
August	16°C	21°C	26°C
September	12°C	18°C	23°C
October	8°C	12°C	15°C
November	4°C	8°C	11°C
December	0°C	3°C	7°C

Grassholme Reservoir: Water Temperature by Location

🇬🇧 United Kingdom > England

Grassholme Reservoir: Weather Forecast

June 9

° / °

slight rain

rain: 100% | wind:

June 10

° / °

dense intensity drizzle

rain: 81% | wind:

June 11

° / °

moderate drizzle

rain: 84% | wind:

June 12

° / °

moderate drizzle

rain: 63% | wind:

June 13

° / °

overcast

rain: 47% | wind:

Location & Local Information

#County Durham

Grassholme Reservoir in County Durham sits high in Teesdale and is fed by cool upland water, so temperatures stay fairly low year-round. In winter the surface typically falls to around 4–8 °C (39–46 °F). Spring can see a gradual rise, often 6–14 °C (43–57 °F) as the weather warms, while summer surface readings commonly range from about 12–18 °C (54–64 °F) on warmer days. In autumn the water cools again to roughly 8–12 °C (46–54 °F). These are typical seasonal surface values; deeper water remains colder and conditions change with weather and inflows.

There is no formal, supervised bathing area at Grassholme and open-water swimming is generally discouraged or restricted. Reasons include cold water that can cause shock, variable depths and submerged hazards, limited access for emergency services, and the reservoir’s role in water supply and fisheries management. Visitors instead use the area for walking, birdwatching and angling. Nearby attractions in Upper Teesdale include scenic riverside trails, nature reserves and the well-known High Force waterfall, making the spot popular for outdoor day visits rather than casual swimming.

Nearby Lakes

Frequently Asked Questions

What is the current water temperature in Grassholme Reservoir?

Water Temperature in Grassholme Reservoir today is 12.6°C.

What is the water temperature in Grassholme Reservoir during the summer months?

The water temperature in Grassholme Reservoir in summer fluctuates in the range of 12°C - 26°C.

Is it possible to swim in Grassholme Reservoir (United Kingdom) and what are the possibilities for this?

Wild swimming at Grassholme Reservoir is generally not permitted for safety and water-supply reasons, but swimming may be possible only as part of organised, supervised events or with prior permission from the reservoir operator, and authorised clubs sometimes run other watersports under agreed conditions.