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Despite having a reputation for strong headwinds (especially during important races!), the Henley Royal Regatta course is actually quite well sheltered. The wooden booms tend (as designed) to dampen the waves, and the banks are not too open to the elements. During other times of the year, however, the booms are completely removed together with all the other Royal Regatta trappings, and the river is more open to the elements as a result. The prevailing wind tends to be cross-tail (southerly or westerly) from one side or another, but sometimes a northerly or easterly winter wind will rip the water up badly, creating wind-against-stream white-capped wavelets which can be difficult for inexperienced rowers to handle. During these conditions you can take shelter under either bank to good effect, or pack the outing in for a trip to the nearest cafe and a bit of "psychological training".
If you visit Henley during the summer you would be unlucky to get more than one or two rainy days, and generally speaking you can expect dry, warm(ish) days and light winds. The best weather is often to be experienced early in the summer, and May can be a glorious month. Early-morning mists are particularly beautiful on this historic stretch of river, and sculling steadily out of the mist around Temple Island into the brightness of a summer's morning can be an experience to put shivers down your spine. Outside the summer months, the weather is often unsettled, with river levels being extremely unpredictable during the early part of the year (January-March).
Current Henley Weather (nearby Reading)
As mentioned above and discussed on the navigation page, the Thames at Henley can be alarmingly prone to flooding nowadays during the winter. This is largely due to changes in land use along the upper Thames, which have swallowed up large tracts of floodplain and reduced the capacity of the water table. All the upper Thames towns now run the risk of flooding whenever there is steady rain for more than 2 days across the region in winter.
The Environment Agency and local clubs have to come to their own agreement about rowing during flood conditions, although in Henley this is modified by the presence of the British national team's heavyweight men's core, which cannot afford to reduce training time unless conditions really do become unsafe. Take local advice from your hosts if you intend to boat when the river is high, and stick to their rules. In general, a high or fast river will make boating from Henley Rowing Club difficult, since the bridge is a significant hazard point, but this can be overcome by boating further downstream by arrangement provided that the river has not actually burst its banks. Boating from the Leander or Upper Thames rafts is less of a problem, but anyone on the river has to be certain that they can handle their shell in the conditions, should turn well away from the lock, and should avoid going through the Bridge. Floods can also lead to fallen trees and other detritus being swept downstream through the open lock sluices, so take a spare fin and keep a sharp eye out for crocodile-looking objects.....
Britain is the home of Greenwich Mean Time (GMT). British Summer Time (BST) runs between 26th March 2000 - 29th October 2000 and is one hour ahead of GMT. The clock changes happen between 1 am and 2 am on the early morning of Sunday.