Aldergrove, 10:00 to 12:00, 1997–2020
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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 3 out of the 24 years, 1.2% of daylight visibility records missing, 0.5% of daylight wind records missing.

This is the analysis for the average of 24 years  (1997–2020).
Time slot: 10:00 to 12:00  (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 3 2 2 3 2 3 3 3 3 2 3 2 ​ 30  8%
≤ 10 mph 7 5 6 8 9 10 11 11 10 7 7 7 ​ 99  27%
≤ 15 mph 12 10 13 14 17 17 18 18 17 14 13 13 ​ 176  48%
≤ 20 mph 14 12 15 17 19 18 19 19 19 16 15 15 ​ 198  54%
≤ 30 mph 14 13 16 18 20 19 20 19 19 18 16 15 ​ 207  57%
≤ 40 mph 15 13 16 19 20 19 20 20 19 18 16 16 ​ 210  57%
any wind 15 13 17 19 20 19 20 20 19 18 16 16 ​ 210  58%
‘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 24 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   +0.1     ​+0.1
≤ 10 mph   +0.1 +0.2 +0.1   +0.3 +0.1   +0.2 +0.2 +0.1   ​+1.3
≤ 15 mph +0.2 +0.3 +0.2 +0.3 +0.1 +0.2 +0.2 +0.1 +0.2 +0.2 +0.2 +0.1 ​+2.3
≤ 20 mph +0.1 +0.3 +0.2 +0.3 +0.1 +0.1 +0.2 +0.1 +0.2 +0.2 +0.2 +0.1 ​+2.1
≤ 30 mph +0.1 +0.2 +0.2 +0.3 +0.1 +0.1 +0.1 +0.1 +0.3 +0.2 +0.1   ​+1.9
≤ 40 mph +0.1 +0.3 +0.2 +0.3 +0.1 +0.2 +0.1 +0.1 +0.3 +0.2 +0.1 +0.1 ​+2.2
any wind +0.1 +0.3 +0.3 +0.3 +0.1 +0.2 +0.1 +0.1 +0.3 +0.2 +0.1 +0.1 ​+2.2
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 25 22 26 27 29 28 29 27 27 27 24 25 ​ 316  86%

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 20 21 19 21 21 21 20 18 18 ​ 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 5 4 4 3 3 4 3 4 4 4 5 5 ​ 47  13%
≤ 10 mph 12 11 10 11 12 14 15 15 13 11 13 14 ​ 150  41%
≤ 15 mph 22 19 22 22 24 25 27 27 25 23 23 23 ​ 284  78%
≤ 20 mph 26 24 27 27 29 28 30 30 28 28 27 27 ​ 331  91%
≤ 30 mph 29 26 30 29 30 30 31 31 29 30 29 29 ​ 353  97%
≤ 40 mph 30 28 31 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, 2021. All rights reserved. The pages and data here are for non-commercial use only.
This page was last edited on 2021-05-09.