Yeovilton, 12:00 to 14:00, 1997–2017
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Met Office station 1302: Yeovilton, Somerset  (BA22 8); OS grid reference: ST 551232.
Coordinates:  N51°00'22" W2°38'24"  (51.006 -2.640), elevation 20 m.
Note: gusts not recorded in 6 out of the 21 years, 1.0% of daylight visibility records missing, 1.6% of daylight precipitation records missing, 0.6% of daylight wind records missing.

This is the analysis for the average of 21 years  (1997–2017).
Time slot: 12:00 to 14:00  (two hours); click below for any-hour analysis, or a different start time, or 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 this timeslot) 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
≤ 5 mph 2 2 2 2 2 3 2 2 2 2 3 3  26  7%
≤ 10 mph 6 5 6 7 7 8 8 8 8 7 7 8  86  23%
≤ 15 mph 11 11 15 16 15 17 18 18 17 15 14 13  181  49%
≤ 20 mph 14 14 19 19 20 21 21 21 21 19 17 16  223  61%
≤ 30 mph 16 16 20 22 22 22 23 22 22 20 18 18  241  66%
≤ 40 mph 17 17 21 22 22 22 23 22 22 21 18 18  246  67%
any wind 17 17 21 22 22 22 23 22 22 21 18 19  247  68%
‘Total’ shows the total flyable days, on average, in a year, and the same as a percentage.

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 this timeslot) 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   −0.2 −0.2 −0.1       −0.6
≤ 10 mph   −0.1       +0.1 −0.1 −0.4         −0.5
≤ 15 mph +0.1   +0.1 +0.3   +0.1 −0.1 −0.4 +0.1 +0.2   +0.1 +0.6
≤ 20 mph     +0.1 +0.3 +0.1 +0.2 −0.1 −0.2   +0.2 −0.1 +0.1 +0.7
≤ 30 mph     +0.1 +0.2 +0.2 +0.1 −0.1 −0.2   +0.1 −0.1   +0.4
≤ 40 mph +0.1   +0.1 +0.2 +0.2 +0.1 −0.1 −0.2   +0.1   +0.1 +0.6
any wind +0.1   +0.1 +0.2 +0.2 +0.1 −0.1 −0.2   +0.1   +0.1 +0.7
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 this timeslot) the visibility was adequate. That is, for the entire timeslot:
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Good days 24 22 26 27 28 27 28 27 27 26 24 24  308  84%

Bad weather analysis

This is the number of days in each month, on average, for which (in this timeslot) no bad weather occurred. That is, for the entire timeslot, 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 21 20 24 23 23 23 23 23 23 22 21 21  268  73%

Wind speed analysis

This is the number of days in each month, on average, for which (in this timeslot) 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 3 3 3 3 2 3 2 3 3 3 4 5  38  10%
≤ 10 mph 11 9 9 9 9 10 10 11 11 9 11 12  120  33%
≤ 15 mph 20 17 20 20 21 22 23 24 22 21 21 21  254  69%
≤ 20 mph 25 23 26 26 27 27 28 28 27 27 26 26  316  87%
≤ 30 mph 29 26 29 29 30 30 30 30 29 30 29 29  351  96%
≤ 40 mph 30 28 30 30 31 30 31 31 30 31 30 31  362  99%

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.