How to read a Met Office forecast for an event
The Met Office forecast table for your site holds most of what an event team needs a week out. This guide sets out what each number means in the Met Office's own words and how far ahead it is worth trusting.
A moment or a period
The Met Office says most numbers in the table are for the moment shown, on the hour. A temperature of 10°C at 10am is the temperature expected at that moment.
The weather symbol, the chance of precipitation and the wind gust are different. They cover the period from the time shown up to the next one, so a shower or gust between the hours still shows.
Wind speed and gust
The speed is the average wind speed expected at that point in time. The Met Office says the wind will strengthen and lull above and below this value.
The gust is the highest wind speed between the time shown and the start of the next period. Strong winds are shown in bold at 25 knots (29mph) or above.
Structure limits are gust limits, so the gust column is the one to compare. The gusts guide explains why.
Chance of rain
The Met Office says a 70% chance means a 7 in 10 chance that precipitation will fall at some point during that period. Precipitation means rain, sleet, snow, hail or drizzle.
The chance is for at least 0.1mm in an hour on the hourly forecast and 0.3mm in three hours on the three hourly forecast. It says nothing about how heavy the rain will be. The weather symbol helps show the difference between light and heavy.
Visibility
The table gives visibility as a letter code. The Met Office calls visibility under 1,000 metres fog.
- VP (very poor): less than 1,000 metres.
- P (poor): 1,001 to 4,000 metres.
- M (moderate): 4,001 to 10,000 metres.
- G (good): 10,001 to 20,000 metres.
Sources: Met Office: What does this forecast mean?; Met Office: What is fog?
Hourly then three hourly
Location forecasts come in hourly steps for the first two days and three hourly steps for days three to seven. Each step takes the hour before and after into account to allow for small variations in timing.
Beyond five days the Met Office says the chaotic nature of the atmosphere begins to play a larger part. It can still forecast the general feel of the weather with Ensemble Forecasting. Local detail becomes harder to give as accurately.
Source: Met Office: About our forecasts
How accurate it is
For autumn 2025 the Met Office checked its forecasts at around 120 sites across the UK. It counted a wind speed forecast as accurate if it was within five knots of what was observed. By that measure 89% of 1-day forecasts were accurate, falling to 77% at the 5-day range.
Those figures are for wind speed, not gusts, over one season.
Using it for an event
- A week out: look for the days to prepare for and treat the detail as provisional.
- Two days out: the forecast moves to hourly steps. Use it for the timing of build, opening and derig.
- On the day: an anemometer at the structure is the reading that counts.
- All week: check the Met Office warnings as well. A warning colour is not a wind speed.
How Gustline helps
Gustline reads the Met Office site-specific forecast for the point you pin. It checks every six hours from a week out and every hour in the final three days. It compares the gust, not the mean, with each structure's limit.
Gustline checks the Met Office site-specific forecast for the point you pin on the map, every six hours from a week out and every hour in the final three days. It compares the forecast gust with the rated limit you enter for each structure and checks the weather alerts you leave on for the event. When a level changes it emails and texts the people you choose. Every alert is logged with a timestamp.
Gustline is an early warning for planning. It does not replace checks on site on the day, the official warnings or your event's own plans.
Plans start at £19 for one event. A season pass is £99 a season and a year pass is £179 a year. It covers the UK only.
Set up alerts for your next eventSources
- Met Office: What does this forecast mean?
- Met Office: What is fog?
- Met Office: About our forecasts
- Met Office: Forecast or reality? How well did the Met Office predict Autumn's wild weather? 23 December 2025
Last updated 4 October 2026.
Read next
- Gusts or mean wind: which number to plan around
Forecasts give a mean wind speed and a gust speed. Why structure limits are gust limits, how load rises with the square of speed and what to compare.
- Met Office weather warnings for event organisers
What yellow, amber and red Met Office warnings mean for an outdoor event. Each colour combines impact and likelihood, so no colour means a set wind speed.
- Heavy rain and waterlogging on event sites
The Met Office counts rain as heavy above 4mm an hour. What MUTA says about saturated ground and anchors and what HSE says about wet surfaces.
- Fog at outdoor events
The Met Office defines fog as visibility under 1,000m and dense fog as under 100m. What that means for event sites and where a forecast helps.
- Snow on marquees and event sites
MUTA says very few fabric structures can take a snow load and that they should be heated to 12°C when snow is possible. HSE advice on gritting.
- Thunderstorm risk at outdoor events
Writing a lightning policy from PLASA guidance: plan for forecast storms, set action distances and know where people can shelter. A forecast is not detection.