Aldergrove, 08:00 to 10:00, 1997–2017
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Met Office station 1450: Aldergrove, County Antrim  (BT29 4); IRL grid reference: 314562E 380950N.
Coordinates:  N54°39'50" W6°13'26"  (54.664 -6.224), elevation 63 m.
Note: gusts not recorded in 4 out of the 21 years, 0.9% of daylight visibility records missing, 0.5% of daylight wind records missing.

This is the analysis for the average of 21 years  (1997–2017).
Time slot: 08:00 to 10:00  (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 1 2 3 3 3 4 4 4 3 3 3 1  34  9%
≤ 10 mph 3 6 8 9 10 11 13 11 10 9 8 2  99  27%
≤ 15 mph 4 10 14 15 18 18 19 18 16 15 13 3  163  45%
≤ 20 mph 5 11 15 17 19 19 20 18 17 17 14 3  175  48%
≤ 30 mph 5 12 16 17 20 19 20 19 17 17 15 3  180  49%
≤ 40 mph 5 12 16 17 20 19 20 19 17 17 15 3  182  50%
any wind 5 12 16 17 20 19 20 19 17 17 15 3  182  50%
‘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   −0.1 +0.1       +0.1     +0.2
≤ 10 mph −0.1 +0.3 +0.1 +0.3   +0.4 +0.2 +0.1 +0.2 +0.2 +0.2 +0.1 +1.9
≤ 15 mph −0.1 +0.3 +0.3 +0.3 +0.2 +0.3 +0.3 +0.2 +0.4 +0.3 +0.2 +0.1 +2.8
≤ 20 mph −0.1 +0.3 +0.2 +0.3 +0.3 +0.3 +0.3 +0.2 +0.3 +0.3 +0.2 +0.1 +2.7
≤ 30 mph   +0.3 +0.2 +0.3 +0.3 +0.3 +0.3 +0.2 +0.4 +0.2 +0.2 +0.1 +2.7
≤ 40 mph   +0.3 +0.2 +0.3 +0.4 +0.3 +0.3 +0.2 +0.4 +0.2 +0.2 +0.1 +2.7
any wind   +0.3 +0.2 +0.3 +0.4 +0.2 +0.3 +0.2 +0.4 +0.2 +0.2 +0.1 +2.7
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 9 21 24 25 27 27 27 26 24 25 24 6  264  72%

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 17 15 19 19 21 20 21 20 20 20 17 17  228  62%

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 6 6 5 5 4 5 5 6 6 6 5 6  64  18%
≤ 10 mph 14 13 14 13 14 15 18 18 16 15 15 14  179  49%
≤ 15 mph 23 21 24 25 26 27 29 29 26 25 25 24  303  83%
≤ 20 mph 26 25 28 28 29 29 30 30 29 29 27 28  340  93%
≤ 30 mph 30 27 30 30 31 30 31 31 30 30 29 30  358  98%
≤ 40 mph 31 28 31 30 31 30 31 31 30 31 30 31  363  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.