If you’ve ever spent more than twenty minutes in the Big Smoke, you know the drill. You check your phone, see a sun icon, walk out the door in a light knit, and three minutes later you’re ducking under a Greggs awning because the sky just opened up. Understanding the weather London per hour isn't just a casual curiosity; it's a survival skill. Honestly, the British capital has some of the most fickle atmospheric moods on the planet.
Today, Sunday, January 18, 2026, is a perfect example of why "daily" averages are basically useless here. While the broad stroke for today suggests a high of 12°C, the hour-by-hour reality is a messy mix of stubborn low clouds, mist, and a slow-moving rain band that’s currently creeping in from the west.
What’s Happening Right Now?
Early birds this morning probably noticed the "pea-souper" vibes. We’ve had extensive areas of low cloud and fog clinging to the Thames since about 4 am. It’s that damp, grey blanket that makes the City look like a scene from a Sherlock Holmes reboot.
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By noon, the Met Office indicates that the fog might start to lift, but don't expect a sudden burst of Mediterranean sunshine. It's more of a "bright grey" transition. Temperatures are hovering around 8°C as we speak, but because the humidity is sitting at a whopping 95%, that air feels a lot sharper than the thermometer suggests.
If you are planning to head out to the Southbank or catch a match later this afternoon, keep a close eye on the 2 pm to 5 pm window. That’s when the mild Atlantic air really tries to assert itself. We might see the mercury hit 11°C or 12°C, which is actually quite warm for mid-January. But—and there is always a "but" in London—that warmth comes with a side of drizzle.
The Science of the "London Microclimate"
Why is the weather London per hour so radically different from, say, Reading or Brighton? It’s the Urban Heat Island effect. London is a massive sprawl of concrete, brick, and glass. This stuff soaks up heat like a sponge.
Professor Adam Scaife, who leads global long-range predictions at the Met Office, has noted that 2026 is shaping up to be one of the warmest years on record globally. In London, this often manifests as "weird" winter days where it’s 13°C one hour and then a biting wind chill the next because the heat trapped by the buildings clashes with Atlantic fronts.
- Morning (6 am - 10 am): High humidity and "stubborn" fog. Visibility is currently less than 0.25 miles in some boroughs.
- Midday (11 am - 2 pm): The "grey lift." Temperatures climb, but the cloud cover remains at about 80-90%.
- Afternoon (3 pm - 6 pm): The warmest part of the day, but also the highest chance of that annoying "vertical mist" that isn't quite rain but definitely gets you wet.
- Evening (7 pm onward): Temperatures stay relatively stable around 9°C. No frost tonight, which is a win for the commuters.
The Beast from the East: A Looming Threat?
While today is mild, the hourly charts for the end of January are starting to look a bit scary. There is a lot of talk among meteorologists about a "battleground" forming over the UK.
On one side, we have the mild Atlantic air we’re breathing today. On the other, a massive high-pressure system over Scandinavia is threatening to shove a "wall of snow" toward the M25 by January 30 or 31. WXCharts is currently forecasting a potential 500-mile stretch of wintry weather.
Is it guaranteed? No.
Forecasting London weather more than 48 hours out is a bit like betting on a coin toss that’s currently mid-air. But the hourly trend for the next fortnight shows a steady decline. We’re going from these 12°C highs down to potentially -2°C by the end of the month.
How to Actually Use Hourly Data
Most people just look at the big number on their app. Don't do that. Look at the "Precipitation Probability" and the "RealFeel."
If the weather London per hour shows a 40% chance of rain, in London, that usually means it will rain, just not everywhere at once. It’ll be a passing shower in Camden while Greenwich stays dry.
Also, check the wind speed. Today it’s a gentle 5-7 mph, but by Wednesday, we’re expecting gusts of 30 mph. A 10°C day with a 30 mph wind feels like 4°C.
Travel Advice for Today and Tomorrow
If you're using the Tube, remember that the "feels like" temperature doesn't apply underground. You’ll be sweating on the Central Line and shivering at the bus stop. Layering is the only way to survive.
- Wear: A water-resistant outer shell. Don't bother with a heavy wool coat today; you'll overheat during the 12°C afternoon peak.
- Carry: A compact umbrella. Even if the hourly says "0% rain," London likes to surprise us.
- Timing: If you want the "clearest" views from the London Eye or The Shard, your best bet today is actually between 3:30 pm and 4:15 pm, just before sunset at 4:24 pm. The low sun might actually break through the cloud deck for a minute or two.
Actionable Forecast Strategy
To stay ahead of the curve, stop relying on the "daily" outlook. Check a high-resolution radar map like the one provided by the Met Office or Netweather every two hours. These use real-time Doppler data to show exactly where the rain bands are.
Tomorrow, Monday, January 19, looks even muddier. We’re expecting "stubborn" fog again in the morning with heavier rain moving in from the south by the afternoon. If you have outdoor plans, try to squeeze them into the 10 am to 1 pm window before the next system arrives.
Keep an eye on the "Yellow Warnings" for fog. They aren't just for drivers; they often cause "knock-on" delays at Heathrow and Gatwick because of reduced runway capacity. If your hourly says "fog" and you're flying, leave for the airport early.