Pembrey Sands, any hour sunrise to sunset, 1997–2015
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Met Office station 1226: Pembrey Sands, Dyfed  (SA17 4); OS grid reference: SN 365043.
Coordinates:  N51°42'47" W4°22'05"  (51.713 -4.368), elevation 3 m.
Note: gusts not recorded in 6 out of the 19 years, 2.2% of daylight visibility records missing, 2.7% of daylight precipitation records missing, 2.1% of daylight wind records missing.

This is the analysis for the average of 19 years  (1997–2015).
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 9 8 12 14 14 14 14 13 13 10 10 9  140  38%  473  10%
≤ 10 mph 14 14 19 21 21 21 21 20 20 17 16 14  217  60%  1266  26%
≤ 15 mph 20 20 25 26 25 26 27 27 25 22 20 20  283  78%  2289  47%
≤ 20 mph 23 24 27 28 28 28 30 29 27 26 24 23  316  86%  2852  58%
≤ 30 mph 28 26 29 30 30 30 31 31 30 30 28 27  348  95%  3450  70%
≤ 40 mph 28 26 30 30 30 30 31 31 30 30 29 29  353  97%  3565  73%
any wind 29 26 30 30 30 30 31 31 30 30 29 29  354  97%  3594  73%
‘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 19 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 −0.2 +0.1     −0.2 +0.3 −0.1 −0.4 +0.1 −0.1 +0.1 −0.1   
≤ 10 mph −0.1 +0.2 +0.1 +0.3 −0.1 +0.2 −0.2 −0.5 +0.2   +0.1 −0.3   
≤ 15 mph −0.1 +0.3   +0.1   +0.1 −0.1 −0.1 +0.2 +0.1   −0.4   
≤ 20 mph −0.1 +0.2 +0.1 +0.1 +0.1       +0.1 +0.2 −0.1 −0.3   
≤ 30 mph     +0.1   +0.1 +0.1   +0.1 +0.1 +0.1 −0.1 −0.2   
≤ 40 mph   +0.1 +0.1   +0.1 +0.1   +0.1 +0.1 +0.1 +0.1 −0.1  +0.1
any wind   +0.1 +0.1   +0.1 +0.1   +0.1 +0.1 +0.1 +0.1 −0.1  +0.1
Empty cells indicate negligible change; ‘Total’ shows the average trend 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 29 27 30 30 31 30 31 31 30 30 29 29  356  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 31 28 31 30 31 30 31 31 30 31 30 31  365  100%

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 9 8 12 14 14 14 14 13 13 10 10 9  140  38%
≤ 10 mph 14 14 19 21 21 21 21 20 20 17 16 14  217  60%
≤ 15 mph 20 20 25 26 25 26 27 27 25 22 20 20  283  78%
≤ 20 mph 23 24 27 28 28 28 30 29 27 26 24 23  316  86%
≤ 30 mph 28 26 29 30 30 30 31 31 30 30 28 27  348  95%
≤ 40 mph 28 26 30 30 30 30 31 31 30 30 29 29  353  97%

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

All text Copyright © Mike Cowlishaw 2008, 2017. All rights reserved. The pages and data here are for non-commercial use only.
This page was last edited on 2017-01-01.