Flying weather analyses   (1997–2020)

Welcome to the Speleotrove flying weather analyses.  I (Mike Cowlishaw ») created these web pages to help answer questions such as:

The emphasis here is for light aircraft, microlights, ultralights, paramotors, model aircraft, etc., and in particular for flying under visual flight rules (VFR »). Only locations in the UK are available.

Click on the name of a station in the summary table below to see an analysis of the data for that station. The analysis shown will be for the 10:00–12:00 time slot. You can change the time slot (or choose ‘any-hour’ or ‘all-day’) while viewing the analysis.

Station “Flyable days”, with wind speed Coordinates
up to 5 mph up to 10 mph up to 20 mph up to 30 mph
Aldergrove, County Antrim  8% 27% 54% 57%  N54°39'50" W6°13'26" 
Brize Norton, Oxfordshire  9% 34% 60% 63%  N51°45'29" W1°34'34" 
Coleshill, Warwickshire †  8% 35% 60% 62%  N52°28'48" W1°41'27"  
Culdrose, Cornwall  3% 16% 42% 49%  N50°05'06" W5°15'25" 
Kirkwall, Orkney  2% 11% 39% 48%  N58°57'14" W2°54'00" 
Manston, Kent  2% 19% 62% 69%  N51°20'46" E1°20'24" 
Odiham, Hampshire  6% 23% 57% 61%  N51°14'17" W0°56'38" 
Pembrey Sands, Dyfed  6% 21% 55% 67%  N51°42'47" W4°22'05" 
Prestwick RNAS, Ayrshire †  8% 27% 55% 60%  N55°30'54" W4°35'06" 
Wittering, Cambridgeshire  4% 20% 58% 65%  N52°36'40" W0°27'32" 
Yeovilton, Somerset  10% 27% 59% 63%  N51°00'22" W2°38'24" 

† These stations have no gusts information recorded.

Flyable days” in this table are those with adequate visibility and no bad weather during the 10:00–12:00 timeslot.

Click on the coordinates next to a station to see its location using Google Maps.

Click here for more detailed summary tables which compare the effects of wind speed and time of day at the different stations.

A few questions and answers ...

Where did the data for these analyses come from?

The meteorological data used are from the Met Office – MIDAS Land Surface Observation Stations Data », which is made available by The British Atmospheric Data Centre » (BADC) This is the Natural Environment Research Council’s » (NERC) Designated Data Centre for the Atmospheric Sciences. The MIDAS data set provides historical hourly weather data for more than 300 weather stations, however, only 107 have current data suitable for the analyses here. The processing needed for the data is described here.

Can you add another station to the list?

Probably, if it is one of those listed in this file. Only those listed record all or most of the meteorological data needed and have current data. If you would like one of these to be added, send me an e-mail (see below). Note that only 47 stations (those stations with a 1 in the rightmost column) have wind gusts data.

What are the criteria used to judge visibility?

For the entire timeslot being analysed:

Of course, for these and the other criteria, conditions considered ‘flyable’ will depend on the pilot (and any passenger), the aircraft, and the intended flight – so these are just intended to give a reasonable guide.

What are the criteria used to judge ‘bad weather’?

For the entire timeslot being analysed, there was no rain, hail, snow, snow on the ground, icing conditions, thunderstorms, etc. This is derived from hourly rainful figures and also from the weather and snow depth reported for each hour (see the WMO Meteorological codes »). The rainfall figures are largely redundant, given the weather codes.

What are the criteria used to judge wind speeds?

For the entire timeslot being analysed the wind speed (including gusts, when recorded) did not exceed the speed shown for the table row in the analysis. The maximum gust is used instead of the average wind speed because lightweight aircraft are usually sensitive to gusts, especially during a crosswind take-off or landing.

What is the difference between ‘any-hour’ and ‘all-day’?

The ‘any-hour’ analysis reports whether any one hour in a day met the criteria being analysed – in other words, a ‘good day’ is one in which it was possible to fly in some one hour; at least one daylight hour was flyable.

The ‘all-day’ analysis reports whether any all hours in a day met the criteria being analysed – in other words, a ‘good day’ is one in which it was possible to fly all day; every daylight hour was flyable.

Does your analysis also include wind gusts due to thermal activity?

Sorry, no, the MIDAS data includes surface winds only. If you know of a source for hourly data of thermal activity at any of the listed stations, please let me know!

Meteorological data often have missing observations – does this affect the results?

The Met Office records are of exceptionally high quality, but inevitably do have occasional gaps. If these affect more than 0.1% of the results then this is noted in the analysis page in the description of the station.


Have another question? Send me (Mike Cowlishaw) an e-mail at


Many thanks to Colin MacKinnon, Joan Walsh, James Hollingshead, and Martin Watson for their feedback and suggestions in the BMAA forums ». And also thanks to the Met Office, BADC, and NERC for making the historical meteorological data available.

Please send any comments, questions, or corrections to me, Mike Cowlishaw, at

All text Copyright © Mike Cowlishaw 2008, 2021. All rights reserved. The pages and data here are for non-commercial use only.
This page was last edited on 2021-05-09.