Five UK Weather Myths That Might Be True

July 31, 2025

3 minute read

Summer in the UK is as unpredictable as ever but that has not stopped a long list of popular myths and sayings from making the rounds every year. The list ranges from old farmer's wisdom to beachside assumptions and we've all heard them. The question is, how many of these weather sayings are based on truth? Can modern weather instruments actually prove or even disprove them? Let's break down some of the most common UK summer weather myths and reveal the truth behind forecasts:

1. "Red sky at night, shepherd's delight. Red sky in the morning, shepherd's warning."

This is probably the best known weather sayings and perhaps that's because it is one of the most reliable ones. The meaning behind it is that when there is a red sky in the evening, good weather is coming. On the other hand, a red sky in the morning means bad weather is on the way. A red sky occurs when sunlight passes through dust particles in a dry atmosphere which is associated with high pressure. In the UK, weather systems generally move west to east. So, a red sky at night in the west often signals stable, dry air approaching. In contrast, a red sky in the morning can mean high pressure has already passed, and bad weather is on its way.

Pro Tip: To help keep an eye on air pressure, try using a barometer or barograph, falling pressure often confirms unsettled weather on the horizon.

2. "You can't get sunburnt when it's cloudy"

It's a common misconception to think that if the sun isn't out, your skin is safe. The truth is UV rays can still penetrate through clouds. In fact, 80% of UV radiation can reach you even on overcast days. Therefore, it is very important to protect your skin with sun cream, even on cloudy days, especially when the UV index is 3 or higher.

3. "If cows lie down, it's going to rain"

This old myth has had many people fooled over the generations but there is actually no strong meteorological evidence linking cows behaviour directly to incoming rains. The original idea behind the myth is that cows are supposedly trying to save a dry patch of grass to lie on but that's not strongly supported by evidence. Cows lie down for many reasons, comfort, rest, not necessarily when rain is coming. That being said, animals do sometimes respond to drops in pressure or humidity such as a swallow.

4. "If it rains on St Swithin's Day (15 July), it will rain for 40 days"

Mid-July often marks a shift in summer weather patterns in the UK. If a high or low pressure system dominates around this time, it can persist due to relatively stable summer jet streams. So while 40 days of rain is pretty unlikely, a wet or dry spell mid-July sometimes does stick around for a while.

Pro Tip: Try using a rain gauge to help track these spells across the season.

5. "If bees stay home, rain will come soon. They fly away, fine will be the day"

The verdict? True! Insects are attuned to the weather and bees in particular are good at predicting bad weather. Bees do not seem to mind little light drizzles, but storms are a threat as their wings can become waterlogged. Low pressure, high humidity, or a sudden drop in temperature can all signal poor flying conditions and the bees will stay instinctively close to the hive. So if you notice a normally busy garden suddenly become quiet, it could be a subtle sign of unsettled weather approaching.

Final Thoughts

British weather comes with centuries of sayings and local wisdom, some rooted in truth, others best taken with a pinch of salt. Thanks to modern weather monitoring tools, we can test these myths for ourselves. Keen weather watchers may keep a detailed record pad others may simply just be curious about the truth behind weather lore. That being said, a few simple instruments such as thermometers, barometers, and instrument screens, can give you real data that can be relied upon. So next time you hear someone say "red sky at night" you'll know exactly what's going on and how to prove it.