How reliable is London Stansted?
Flights from STN avoided significant airline-controlled delay in 68% of 423,114 flights in official UK CAA history — and weather is calmest in Jul. Here’s the full picture before you book.
Reliability score
on-time, cancellations & delays
Weather favorability
year-round climate
Origin-airport operations
What the airline-controlled delay record at STN looks like
Avoided 15+ min controlled delay
across 423,114 flights
Source: UK CAA. Origin-grouped, cause-attributed operational history; it is not a direct departure-punctuality measure or a guarantee for any flight.
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Weather by month
When the weather works for you at London
A calm-weather score (0–100) for each month from decades of airport observations — how often conditions disrupt flying, not temperature. Higher is calmer.
Calmest month
Calmest flying weather of the year · 97/100 favorability
Roughest month
Most disruptive — low visibility & fog, freezing conditions · 83/100 favorability
The read on STN
What the numbers say about flying through London Stansted
Across official performance history, flights from London avoided significant airline-controlled delay about 68% of the time over 423,114 flights. That's a middling record — neither a strength nor a red flag on its own. Pair it with a low cancellation rate of 0.3%, so flights here rarely vanish outright. When a departure does run late, the typical delay is around 17 minutes.
On weather, London is an unusually calm-weather airport year-round. July is the calmest stretch for flying, scoring 97 out of 100 for favorable conditions, while December is the most disruptive at 83, driven mainly by low visibility & fog and freezing conditions. The year is relatively steady, so no single month stands out as one to avoid on weather alone.
None of this guarantees your specific flight — it’s the backdrop. To turn it into a booking, score real flights to London, read how we weigh it all in how the PlaneSane Score works, and brush up with how to pick a reliable flight and avoiding weather delays.
Common questions about STN
- How reliable is London Stansted (STN)?
- Flights from London avoided significant airline-controlled delay roughly 68% of the time across 423,114 flights of official history — a middling record — neither a strength nor a red flag on its own. The cancellation rate runs about 0.3%. It's advisory context, not a guarantee for any single flight.
- What is the best month to fly from STN for good weather?
- July has the calmest flying weather at London Stansted. December is the most disruptive, mainly from low visibility & fog and freezing conditions.
Planning a trip through London?
Score real flights to and from STN on reliability, weather, and connection safety — not just price.