Pembrey Sands, sunrise to sunset, 1997–2017
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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 21 years, 2.3% of daylight visibility records missing, 2.8% of daylight precipitation records missing, 2.2% of daylight wind records missing.

This is the analysis for the average of 21 years  (1997–2017).
Time slot: sunrise to sunset  (all daylight hours); click below on any-hour, or on the start time for a specific 2-hour slot (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 all daylight hours) 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 0 0 0 0 0 0 0 0 0 0 0 1  2  0%
≤ 10 mph 2 1 1 1 1 1 1 1 1 2 2 3  16  4%
≤ 15 mph 6 4 5 4 4 5 5 6 6 7 6 6  65  18%
≤ 20 mph 8 7 8 8 8 9 10 9 9 9 8 8  101  28%
≤ 30 mph 10 9 11 12 12 12 13 13 13 12 10 12  141  38%
≤ 40 mph 11 10 12 13 13 13 14 14 14 13 11 12  150  41%
any wind 11 11 12 13 13 13 14 14 14 14 12 13  154  42%
‘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 all daylight hours) 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
≤ 10 mph −0.1   −0.1                   −0.1
≤ 15 mph −0.1 +0.1 −0.1 +0.1 −0.1     −0.1 +0.1 +0.2 +0.2 −0.1 +0.2
≤ 20 mph −0.2 +0.3 −0.1 +0.2   +0.2 +0.1 +0.1 +0.2 +0.3 +0.1   +1.1
≤ 30 mph −0.1 +0.4   +0.4 +0.2 +0.2 +0.3 +0.3 +0.3 +0.5 +0.2   +2.5
≤ 40 mph −0.1 +0.4   +0.4 +0.3 +0.3 +0.3 +0.4 +0.3 +0.6 +0.2   +3.1
any wind   +0.4   +0.4 +0.3 +0.3 +0.3 +0.4 +0.3 +0.6 +0.3 +0.1 +3.5
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 all daylight hours) the visibility was adequate. That is, for the entire day:
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
Good days 16 14 15 18 17 16 16 17 18 18 18 18  201  55%

Bad weather analysis

This is the number of days in each month, on average, for which (in all daylight hours) no bad weather occurred. That is, for the entire day, 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 18 17 20 19 19 19 20 19 20 18 16 18  223  61%

Wind speed analysis

This is the number of days in each month, on average, for which (in all daylight hours) 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 1 1 0 0 1 0 0 0 0 1 1 2  7  2%
≤ 10 mph 5 3 3 1 2 1 2 2 3 4 5 6  37  10%
≤ 15 mph 12 9 11 9 10 10 9 10 11 11 11 13  127  35%
≤ 20 mph 16 15 18 17 17 17 17 17 17 15 15 16  197  54%
≤ 30 mph 23 23 26 27 27 27 28 28 26 25 23 24  305  83%
≤ 40 mph 27 26 29 29 30 29 31 30 29 29 27 28  345  95%

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.