Brize Norton, any hour sunrise to sunset, 1997–2017
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Met Office station 605: Brize Norton, Oxfordshire  (OX18 3); OS grid reference: SP 292067.
Coordinates:  N51°45'29" W1°34'34"  (51.758 -1.576), elevation 81 m.
Note: gusts not recorded in 4 out of the 21 years.

This is the analysis for the average of 21 years  (1997–2017).
Time slot: sunrise to sunset  (any daylight hour); click below on the start time for a specific 2-hour slot, or on all-day for whole day analysis (all times are GMT):

any-hour  06:00  08:00  10:00  12:00  14:00  16:00  18:00  all-day

‘Flyable days’ analysis

This is the number of days in each month, on average, for which (in some daylight hour) the visibility was adequate, and there was no bad weather, and the wind speed was less than or equal to that shown on the left.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total Hours
≤ 5 mph 10 11 13 17 18 22 23 23 19 15 13 11  195  53%  764  16%
≤ 10 mph 19 20 23 25 27 28 30 30 27 25 22 20  294  81%  2003  41%
≤ 15 mph 25 24 28 29 30 29 31 31 29 29 26 24  335  92%  2884  59%
≤ 20 mph 26 25 29 29 30 30 31 31 29 29 27 25  341  93%  3026  62%
≤ 30 mph 26 25 29 29 30 30 31 31 29 29 27 25  343  94%  3132  64%
≤ 40 mph 26 25 29 29 30 30 31 31 29 29 27 25  343  94%  3155  65%
any wind 27 26 29 29 30 30 31 31 29 29 27 25  344  94%  3157  65%
‘Total’ shows the total flyable days, on average, in a year, and the same as a percentage.
‘Hours’ shows the total flyable hours, on average, in a year, and the same as a percentage of total daylight hours.

Trend analysis

This is the average change (per year, over the 21 years) in the average number of days in each month for which (in some daylight hour) the visibility was adequate, and there was no bad weather, and the wind speed was less than or equal to that shown on the left.

For example, if a value of +0.5 is shown for a given month then that implies that since 1997 the number of flyable days in that month has increased by (on average) half a day per year.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
≤ 5 mph       +0.1 −0.1     −0.1 +0.1     +0.1 +0.1
≤ 10 mph   −0.1 +0.1 +0.1 −0.1 +0.1 +0.1 −0.1 +0.1 +0.1   +0.1 +0.4
≤ 15 mph −0.1 −0.1 +0.1             +0.1 −0.1 +0.1 −0.1
≤ 20 mph −0.2 −0.1 +0.1             +0.1     −0.3
≤ 30 mph −0.2 −0.2 +0.1                   −0.2
≤ 40 mph −0.2 −0.1 +0.1                   −0.2
any wind −0.2 −0.1 +0.1                   −0.1
Empty cells indicate negligible change; ‘Total’ shows the sum of the trends over the whole year.

Visibility analysis

This is the number of days in each month, on average, for which (in some daylight hour) the visibility was adequate. That is, for the entire hour:
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Good days 28 27 30 30 31 30 31 31 30 30 28 27  353  97%

Bad weather analysis

This is the number of days in each month, on average, for which (in some daylight hour) no bad weather occurred. That is, for the entire hour, there was no rain, hail, snow, snow on the ground, icing conditions, thunderstorms, etc.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Good days 29 27 30 30 31 30 31 31 30 30 29 29  355  97%

Wind speed analysis

This is the number of days in each month, on average, for which (in some daylight hour) the maximum (gust) wind speed was less than or equal to the value shown on the left.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
≤ 5 mph 10 11 13 17 18 22 23 23 19 15 13 11  195  53%
≤ 10 mph 19 20 23 25 27 28 30 30 27 25 22 20  294  81%
≤ 15 mph 25 24 28 29 30 29 31 31 29 29 26 24  335  92%
≤ 20 mph 26 25 29 29 30 30 31 31 29 29 27 25  341  93%
≤ 30 mph 26 25 29 29 30 30 31 31 29 29 27 25  343  94%
≤ 40 mph 26 25 29 29 30 30 31 31 29 29 27 25  343  94%

Please send any comments, questions, or corrections to me, Mike Cowlishaw, at mfc@speleotrove.com.

All text Copyright © Mike Cowlishaw 2008, 2018. All rights reserved. The pages and data here are for non-commercial use only.
This page was last edited on 2018-02-09.