Guernsey Weather Fox

Seven day Guernsey weather forecast for 21 June 2026

Image uploaded by Jim G

Monday to Thursday

Weather

I’m splitting the week into its hot half and cool half, and clumping all days within those halves together, because the differences will be minimal and mostly of little interest in the context of the long hot days and short tropical nights. These four days will all be sunny and dry, with light E’ly breezes, unless Thursday goes on to turn cloudy and perhaps thundery. Monday and Tuesday are currently expected to peak around 31-32°C, which we all know is V-hot for this part of the world. Wednesday however could potentially be as hot as 33-34°C, which is a temperature that we generally expect to head to the Med for. Thursday might also hit these dizzy heights… it all depends on whether it turns cloudy or not. As you all know, we have just had the solstice, so the nights are at their absolute shortest right now, allowing very little recovery without the assistance of air-con. Min temps are likely to be between 20 and 22°C each night… hopefully (but not definitely) 3-4°C lower on Thursday night. Top tips, which you probably already know, windows and blinds all closed to keep the heat out in the daytime, only opening again for some relative freshness between the hours of 10/11pm and 8/9am. Best not to burn any fires, especially disposable barbecues. And please be even more careful than usual, not to litter the environment with anything made of glass.

Surf and the Water

Flat surf but fantastic swimming conditions. What more could you wish for in this kind of heat. Don’t forget to protect your skin during the hours of high UV (roughly 10am to 4pm). Long loose clothing and wide-rim hats obviously being the best choice of all. Low tides will be in the mornings, shuffling forward incrementally from around 7am on Monday to 10am on Thursday. High tides in the afternoons, shuffling and shrinking from roughly 7.4m at 1pm Monday to roughly 7.1m at 4pm Thursday.

Friday and The Weekend

Weather

Ok, the last time I said that we would see a switch of wind direction to a N’ly direction, plummeting the max temps into the very low twenties, the computer models subsequently changed their story to the opposite extreme. Hopefully this won’t happen again, but I guess it would be wise to remember that no forecast is ever set in stone. On this occasion, it looks as though winds will actually go SW’ly, which is a feature of more typical weather patterns in this part of the world and, as such, the computer models are very well programmed to handle them. So yes, my gut feeling is that this prediction is a more reliable one. And if it is the case, the switch from such heat to such humidity is likely to lead to both thunderstorms and fog banks… maybe the former will come first, maybe the latter, or maybe both together. Whatever the combo/sequence, we will probably see a 10°C drop in the daily maxima (relative to the first chunk of the week) and most mercifully a similar drop in the nightly minima.

Surf and the Water

The surf should become rideable again, with wave heights picking up to 3-4 feet by Saturday afternoon, and maybe sustaining that size through Sunday. Swimming conditions will be best in the north and east. Tides will be low in the late morning/lunchtime. Highs will be around dawn and dinnertime (7.4m, 7.7m and 8m respectively).

The next forecast update will be on Wednesday…

Previous Weather Fox Forecasts

Tide Tables
Swim Conditions
Ormering
Lihou Causeway

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