When to Swim
As to when there is a good time to swim in the English Channel – there isn’t one.
The weather in the English Channel is very unpredictable and there are no known “calm periods” as such. You take the weather as it comes and should prepare for every eventuality. You will be starting your swim at times that are set by the tides – often in the early hours with swim periods in the dark. Swims usually start in the dark or they finish in the dark. Training in the dark is essential to prepare yourself for the swim of 18.5 to 20 nautical miles, around 35/37 kilometres – if you are lucky
The English Channel swim is one of the top open water swims of the World, (if not the top), due to the many different elements surrounding it. It is far from an easy swim or one for swimmers without a good amount of experience. The English Channel is a mental swim as well as a physical one that requires a lot of positive thought. You will find a lot of information on the CS&PF web site www.cspf.co.uk and in swimmer’s groups online.
You are swimming in
- Cold (16°C to 18°C) water temperatures
- Sudden changes in sea conditions from Flat calm to large waves & vice versa
- Weather conditions can be unpredictable and not as forecast
- You are crossing one of the busiest shipping lanes in the world.
JUNE has longest days that are often warm and sunny, but the water is still warming up and only around the 14°C mark. Usually for experienced swimmers that know their capabilities, are members of a relay team or wearing wet suits.
JULY still has the long days and, usually the warmer ones, but the water temperature is still only around the 15°C at the beginning of the month. It increases slowly to 16°C (60°F) – perhaps a bit more at the end of July.
AUGUST starts at around the 16/17 °C and can increase to 18°C by the end of the month. Sometimes it can go even higher. The days are however getting shorter and the wind factor is more unpredictable with sea and land breezes to contend with.
SEPTEMBER / OCTOBER is when the water is usually at its warmest 17 / 18°C, but the days are getting colder and shorter.
The wind direction as well as its speed is an important factor affecting your swim in many ways.
SW & NE winds are either with the tidal direction or against the tidal direction and conditions change considerably every 6 hours when the tide changes its tidal flow by 180°. This change happens quickly, usually within 20 to 30 minutes.
NW winds are behind you and push from England to France across the tidal flow often assisting your swim but making the handling on the escort boat harder.
SE winds are in your face and push from France to England across the tidal flow. Not a comfortable swim.
The other wind positions all affect the sea conditions differently.
The wind strength is a major factor that creates the sea conditions when added to the wind direction and tidal flow but need to be considered over a much longer period prior to the swim starting.
To the ambient wind direction, we as pilots, consider land and sea breezes that are created along the shoreline areas. These are created by the difference between the land and sea temperatures and change constantly throughout the day/ night.
The “average” swim times are around 12 to 16 hours in duration, some longer, a few shorter. The Dover Straits / Nor Par de Calais area has tides that change direction by 180° approximately every 6 hours.
The two tidal directions are known as the: –
FLOOD tide (over high water) and EBB tide (over low water).
The FLOOD TIDE runs up the Channel towards Holland in a North Easterly direction from about 2 hours before high water Dover to around 4.5 hours after high water Dover.
The EBB TIDE then runs down Channel in a South Westerly direction towards the Atlantic from approximately 4.5 hours after high water to 2 hours before high water Dover. There can be short “slack water” periods when the tide turns depending on the conditions.
These are very flexible “estimated times” – both tide times and tidal flow can vary from the predicted estimates depending on the weather conditions and wind strength and direction.
Bookings are listed in tidal periods with various amount of days per period
They are split into about 7-day periods: High Springs – Neaps – Low Springs – Neaps
These periods are reflected in the High-water times predicted for the port of Dover for Channel swims.
- NEAP TIDES (are for the periods when High water Dover is below 6.1 metres)
- SPRING TIDES (are for the periods when High water Dover is above 6.1 metres).
- LOW Spring tide period is when the moon is FULL (opposite side of the earth to the sun)
- HIGH Spring tide period is when the moon is NEW (same side of the earth as the sun).
- NEAP TIDE is when the moon is a 90° to the Earth /Sun axis.
The choice of Springs or Neaps is a personal one that is up to the swimmers to make. It does not really matter from the pilot’s point of view; it’s just that the mental side of getting your head around it can be a problem. These days with all the modern electronics onboard the pilot boat the navigation is much easier and there is little or no time difference between swims completed on Springs or Neaps.
The sea often settles quicker on Spring tides after a period of strong winds and is often flatter in light winds, however in a wind against tide situation with the wind building then the sea can be rougher.
The sea needs time to settle (around 24 hours) after a period of wind on a Neap tide as the tidal movement is much slower. This can cause a short-confused sea.
This part of the swim has been seen many times, the support team is a “oh I need someone to feed me” or a after thought. Without a good support team you will not have a successful swim. Get your support team sorted early, we will add further information on feeding equipment in the coming weeks
Basically, if you prepare yourself well you will be able to swim at any time. If you do not get the training and the experience sorted, you will struggle whenever you make the attempt.