Fingal Wildlife Centre
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fingal Wildlife Centre clear sky chart from 2005-11-06 to 2024-11-06.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	14% 9% 3 8% 5% 5% 5% 4 6% 8% 33%	101891
	Night	15% 10% 3 8% 5% 4 5% 4 6% 7% 34%	97108
Transparency	Day	47% 5% 14% 22% 11% 1	105533
	Night	48% 4 13% 21% 12% 1	101606
Seeing	Day	17% 6% 26% 29% 17% 6%	15001
	Night	20% 6% 26% 31% 15% 2	24094

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 16% 5% 12% 7% 6% 5% 4 4 4 20%	2754
	11th to 20th	Day	13% 19% 7% 15% 7% 7% 5% 4 7% 4 10%	2840
	21st to end	Day	25% 19% 6% 11% 6% 5% 4 3 4 3 14%	3124
February	1st to 10th	Day	15% 16% 4 12% 8% 5% 5% 3 5% 6% 19%	1710
	11th to 20th	Day	15% 12% 5% 11% 7% 8% 5% 4 4 6% 24%	1672
	21st to end	Day	18% 11% 4 11% 6% 5% 5% 4 5% 5% 24%	1570
March	1st to 10th	Day	20% 11% 4 10% 6% 5% 5% 4 5% 5% 26%	3357
	11th to 20th	Day	12% 12% 4 10% 6% 5% 5% 4 5% 7% 31%	3480
	21st to end	Day	18% 9% 3 8% 6% 5% 5% 3 5% 5% 33%	3815
April	1st to 10th	Day	15% 11% 4 7% 6% 5% 4 4 6% 8% 31%	2152
	11th to 20th	Day	17% 10% 3 6% 5% 5% 5% 3 6% 7% 33%	2424
	21st to end	Day	18% 9% 3 7% 5% 5% 4 3 5% 6% 35%	2470
May	1st to 10th	Day	17% 7% 3 8% 5% 5% 5% 4 6% 7% 33%	4082
	11th to 20th	Day	15% 9% 3 8% 5% 5% 5% 6% 7% 9% 28%	4081
	21st to end	Day	10% 5% 2 6% 4 4 4 4 6% 8% 46%	4782
June	1st to 10th	Day	10% 6% 2 7% 6% 4 6% 5% 6% 8% 41%	2660
	11th to 20th	Day	9% 5% 3 6% 4 5% 5% 6% 8% 9% 41%	2798
	21st to end	Day	10% 5% 2 6% 4 4 5% 5% 8% 9% 42%	2850
July	1st to 10th	Day	8% 5% 2 6% 4 5% 5% 4 6% 11% 42%	4707
	11th to 20th	Day	8% 5% 2 5% 4 4 4 4 7% 11% 45%	4155
	21st to end	Day	7% 4 2 6% 5% 5% 5% 5% 7% 10% 44%	4466
August	1st to 10th	Day	14% 5% 2 5% 4 4 5% 5% 7% 8% 40%	4104
	11th to 20th	Day	8% 6% 2 7% 5% 5% 7% 5% 8% 11% 36%	4044
	21st to end	Day	8% 6% 2 7% 5% 5% 5% 4 7% 9% 43%	4473
September	1st to 10th	Day	9% 6% 2 6% 4 5% 5% 4 6% 8% 44%	2217
	11th to 20th	Day	9% 5% 2 5% 5% 4 5% 4 6% 8% 47%	2090
	21st to end	Day	18% 6% 2 6% 4 5% 4 4 7% 8% 37%	2090
October	1st to 10th	Day	14% 7% 2 7% 5% 4 4 4 6% 8% 39%	1945
	11th to 20th	Day	19% 9% 3 8% 4 4 5% 4 6% 7% 31%	1900
	21st to end	Day	22% 10% 3 8% 5% 5% 5% 3 5% 6% 25%	2059
November	1st to 10th	Day	13% 9% 3 8% 5% 6% 5% 4 7% 8% 33%	1717
	11th to 20th	Day	16% 10% 3 7% 5% 5% 5% 4 6% 7% 31%	1581
	21st to end	Day	20% 12% 4 9% 6% 6% 6% 4 6% 6% 21%	1520
December	1st to 10th	Day	18% 14% 4 11% 6% 5% 4 3 6% 7% 20%	1520
	11th to 20th	Day	19% 14% 6% 11% 7% 5% 5% 4 6% 6% 18%	1910
	21st to end	Day	28% 19% 6% 11% 6% 4 4 3 4 4 11%	2772
January	1st to 10th	Night	18% 16% 6% 10% 6% 5% 5% 3 4 6% 21%	4173
	11th to 20th	Night	16% 18% 6% 14% 6% 6% 5% 4 9% 4 12%	4120
	21st to end	Night	25% 17% 6% 10% 6% 4 4 3 4 5% 16%	4532
February	1st to 10th	Night	17% 16% 5% 9% 6% 5% 4 4 6% 6% 22%	2470
	11th to 20th	Night	16% 13% 5% 8% 6% 6% 4 4 5% 6% 26%	2391
	21st to end	Night	19% 11% 4 9% 7% 5% 5% 4 5% 6% 25%	1884
March	1st to 10th	Night	19% 10% 4 9% 6% 4 4 3 5% 6% 31%	3494
	11th to 20th	Night	12% 8% 3 6% 5% 5% 5% 4 6% 8% 38%	3480
	21st to end	Night	16% 9% 4 8% 4 4 4 3 5% 5% 38%	3817
April	1st to 10th	Night	19% 10% 3 6% 4 5% 4 4 5% 6% 35%	2027
	11th to 20th	Night	17% 8% 3 7% 5% 5% 5% 3 5% 7% 37%	1720
	21st to end	Night	15% 8% 2 7% 5% 5% 4 4 5% 6% 37%	1710
May	1st to 10th	Night	19% 9% 3 6% 4 4 4 3 5% 8% 35%	2813
	11th to 20th	Night	12% 8% 3 8% 6% 6% 6% 4 6% 7% 34%	2812
	21st to end	Night	10% 5% 3 5% 4 3 4 4 6% 8% 48%	2772
June	1st to 10th	Night	12% 6% 2 5% 5% 3 4 4 7% 8% 45%	1520
	11th to 20th	Night	9% 5% 2 6% 3 5% 5% 4 8% 9% 43%	1377
	21st to end	Night	11% 4 1 5% 5% 5% 4 4 5% 8% 47%	1330
July	1st to 10th	Night	7% 4 2 5% 4 3 5% 3 5% 11% 50%	2258
	11th to 20th	Night	8% 5% 2 5% 3 3 4 3 6% 10% 52%	2801
	21st to end	Night	6% 4 2 4 4 5% 5% 5% 8% 9% 49%	3087
August	1st to 10th	Night	11% 6% 2 6% 4 4 5% 4 7% 8% 44%	2825
	11th to 20th	Night	8% 6% 2 6% 4 4 4 4 5% 7% 50%	2785
	21st to end	Night	8% 5% 2 6% 4 4 5% 3 6% 8% 49%	3151
September	1st to 10th	Night	8% 6% 3 7% 4 4 5% 3 6% 6% 48%	1960
	11th to 20th	Night	9% 4 1 5% 4 4 4 4 5% 7% 54%	2090
	21st to end	Night	15% 6% 2 7% 4 5% 4 3 6% 6% 40%	2090
October	1st to 10th	Night	14% 5% 2 7% 4 4 4 3 5% 7% 45%	2233
	11th to 20th	Night	17% 8% 3 8% 4 4 4 4 5% 7% 36%	2280
	21st to end	Night	21% 9% 3 7% 4 4 5% 4 6% 6% 31%	2536
November	1st to 10th	Night	14% 8% 2 5% 4 4 5% 4 5% 7% 41%	2483
	11th to 20th	Night	16% 9% 3 8% 5% 5% 6% 4 6% 7% 31%	2598
	21st to end	Night	21% 12% 3 8% 5% 4 4 4 6% 6% 26%	2660
December	1st to 10th	Night	20% 14% 5% 9% 6% 4 4 3 5% 7% 22%	2660
	11th to 20th	Night	17% 17% 5% 9% 6% 5% 4 3 5% 5% 23%	3285
	21st to end	Night	28% 17% 6% 10% 5% 5% 4 3 4 4 14%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	68% 2 13% 12% 4	2755
	11th to 20th	Day	75% 2 11% 8% 3	2840
	21st to end	Day	75% 3 10% 8% 4	3124
February	1st to 10th	Day	66% 3 10% 14% 6% 1	1710
	11th to 20th	Day	61% 5% 9% 16% 8% 1	1681
	21st to end	Day	60% 5% 11% 17% 6% 1	1570
March	1st to 10th	Day	60% 4 9% 21% 5% 1	3357
	11th to 20th	Day	51% 5% 17% 19% 7% 1	3480
	21st to end	Day	50% 6% 11% 20% 12% 1	3815
April	1st to 10th	Day	50% 3 12% 21% 13%	2152
	11th to 20th	Day	49% 4 12% 20% 13% 1	2424
	21st to end	Day	49% 4 12% 20% 12% 2	2470
May	1st to 10th	Day	48% 5% 12% 21% 11% 3	4120
	11th to 20th	Day	51% 5% 17% 19% 8% 1	4085
	21st to end	Day	35% 4 14% 23% 19% 6%	4796
June	1st to 10th	Day	39% 5% 13% 28% 13% 2	2660
	11th to 20th	Day	36% 7% 14% 23% 18% 2	2798
	21st to end	Day	35% 6% 14% 27% 17% 1	2850
July	1st to 10th	Day	35% 5% 14% 28% 15% 3	4634
	11th to 20th	Day	31% 5% 16% 32% 15% 1	4084
	21st to end	Day	32% 7% 18% 22% 20% 2	4324
August	1st to 10th	Day	39% 6% 16% 24% 14% 1	4091
	11th to 20th	Day	38% 6% 17% 29% 9% 1	4083
	21st to end	Day	36% 5% 13% 32% 13% 1	4473
September	1st to 10th	Day	36% 5% 17% 26% 14% 2	2217
	11th to 20th	Day	33% 4 15% 32% 17%	2090
	21st to end	Day	44% 5% 13% 25% 13% 1	2090
October	1st to 10th	Day	34% 6% 15% 25% 20% 1	3231
	11th to 20th	Day	41% 4 13% 26% 16% 1	3140
	21st to end	Day	48% 4 17% 24% 7%	3373
November	1st to 10th	Day	47% 5% 12% 24% 9% 2	1717
	11th to 20th	Day	51% 4 18% 16% 10% 1	1581
	21st to end	Day	64% 3 14% 15% 3	1520
December	1st to 10th	Day	63% 5% 13% 15% 4	1520
	11th to 20th	Day	67% 3 15% 10% 4	1906
	21st to end	Day	77% 3 11% 7% 2	2772
January	1st to 10th	Night	65% 3 13% 13% 6%	4173
	11th to 20th	Night	73% 2 13% 8% 3	4120
	21st to end	Night	72% 3 10% 11% 3	4532
February	1st to 10th	Night	61% 5% 11% 16% 6% 1	2470
	11th to 20th	Night	58% 4 10% 18% 9% 1	2393
	21st to end	Night	59% 4 9% 20% 8% 1	1884
March	1st to 10th	Night	54% 3 13% 21% 7%	3494
	11th to 20th	Night	43% 5% 15% 20% 15% 1	3480
	21st to end	Night	47% 4 10% 21% 16% 2	3817
April	1st to 10th	Night	50% 4 9% 21% 14% 2	2027
	11th to 20th	Night	47% 4 9% 23% 16% 2	1720
	21st to end	Night	46% 3 10% 21% 16% 3	1710
May	1st to 10th	Night	47% 3 10% 20% 14% 5%	2840
	11th to 20th	Night	48% 4 13% 22% 10% 2	2813
	21st to end	Night	34% 3 13% 23% 23% 3	2779
June	1st to 10th	Night	37% 4 11% 28% 17% 3	1520
	11th to 20th	Night	35% 3 15% 26% 19% 3	1377
	21st to end	Night	35% 6% 11% 26% 21% 1	1330
July	1st to 10th	Night	30% 4 11% 29% 19% 7%	2222
	11th to 20th	Night	29% 5% 13% 33% 19% 2	2749
	21st to end	Night	29% 7% 16% 23% 21% 3	2988
August	1st to 10th	Night	36% 5% 13% 27% 16% 2	2814
	11th to 20th	Night	33% 5% 14% 32% 14% 1	2812
	21st to end	Night	32% 5% 11% 34% 17% 1	3151
September	1st to 10th	Night	35% 4 12% 30% 16% 2	1960
	11th to 20th	Night	31% 3 12% 32% 20% 2	2090
	21st to end	Night	44% 3 12% 26% 13% 1	2090
October	1st to 10th	Night	28% 3 10% 31% 27% 2	3727
	11th to 20th	Night	42% 4 13% 23% 18%	3779
	21st to end	Night	41% 3 16% 27% 13% 1	4172
November	1st to 10th	Night	43% 3 12% 26% 15% 1	2483
	11th to 20th	Night	52% 3 13% 21% 10% 1	2598
	21st to end	Night	59% 2 17% 17% 5% 1	2660
December	1st to 10th	Night	63% 2 14% 16% 5%	2660
	11th to 20th	Night	63% 3 14% 14% 5%	3288
	21st to end	Night	75% 3 12% 8% 2	4884

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	24% 12% 34% 22% 6% 2	249
	11th to 20th	Day	24% 9% 43% 17% 6% 2	270
	21st to end	Day	27% 9% 31% 28% 5% 1	297
February	1st to 10th	Day	21% 13% 39% 24% 4	270
	11th to 20th	Day	21% 14% 36% 24% 4	270
	21st to end	Day	22% 19% 37% 19% 2	225
March	1st to 10th	Day	20% 10% 34% 25% 10%	404
	11th to 20th	Day	17% 11% 32% 30% 8% 1	460
	21st to end	Day	25% 8% 33% 26% 8% 1	506
April	1st to 10th	Day	19% 7% 34% 29% 9% 2	460
	11th to 20th	Day	25% 7% 33% 20% 10% 5%	452
	21st to end	Day	23% 5% 32% 27% 10% 3	460
May	1st to 10th	Day	22% 4 27% 30% 13% 4	463
	11th to 20th	Day	17% 3 22% 30% 20% 7%	487
	21st to end	Day	12% 2 23% 30% 23% 10%	529
June	1st to 10th	Day	12% 2 26% 35% 18% 7%	490
	11th to 20th	Day	9% 4 23% 35% 24% 5%	628
	21st to end	Day	12% 3 24% 36% 21% 5%	680
July	1st to 10th	Day	8% 3 17% 33% 27% 12%	671
	11th to 20th	Day	13% 2 18% 29% 25% 12%	504
	21st to end	Day	9% 1 13% 37% 29% 11%	532
August	1st to 10th	Day	10% 2 15% 33% 24% 16%	486
	11th to 20th	Day	10% 1 12% 36% 28% 13%	479
	21st to end	Day	12% 1 13% 35% 29% 10%	539
September	1st to 10th	Day	12% 2 17% 32% 27% 11%	490
	11th to 20th	Day	9% 1 13% 26% 34% 17%	490
	21st to end	Day	20% 4 20% 26% 22% 8%	490
October	1st to 10th	Day	18% 5% 23% 24% 21% 9%	490
	11th to 20th	Day	20% 9% 31% 28% 9% 3	490
	21st to end	Day	26% 9% 31% 24% 9% 1	508
November	1st to 10th	Day	17% 10% 35% 22% 12% 4	285
	11th to 20th	Day	21% 15% 33% 22% 5% 3	209
	21st to end	Day	24% 9% 37% 24% 4	180
December	1st to 10th	Day	25% 13% 35% 19% 7% 1	180
	11th to 20th	Day	29% 19% 29% 17% 6%	180
	21st to end	Day	30% 13% 31% 21% 4 1	198
January	1st to 10th	Night	26% 13% 36% 18% 6% 1	760
	11th to 20th	Night	30% 12% 28% 23% 6%	760
	21st to end	Night	24% 8% 33% 28% 7%	836
February	1st to 10th	Night	26% 8% 34% 28% 4	760
	11th to 20th	Night	23% 9% 33% 29% 5% 1	743
	21st to end	Night	23% 9% 37% 26% 4	628
March	1st to 10th	Night	20% 7% 34% 31% 8%	760
	11th to 20th	Night	20% 6% 35% 29% 9% 1	760
	21st to end	Night	22% 6% 29% 30% 11% 1	836
April	1st to 10th	Night	23% 7% 29% 32% 7% 1	760
	11th to 20th	Night	21% 5% 31% 30% 12% 1	596
	21st to end	Night	20% 3 31% 34% 11% 1	570
May	1st to 10th	Night	20% 3 25% 34% 16% 2	570
	11th to 20th	Night	15% 2 21% 41% 18% 3	561
	21st to end	Night	14% 2 18% 36% 26% 4	439
June	1st to 10th	Night	17% 1 22% 38% 20% 3	380
	11th to 20th	Night	12% 2 19% 40% 25% 2	380
	21st to end	Night	12% 1 20% 43% 22% 2	380
July	1st to 10th	Night	7% 1 13% 40% 34% 5%	391
	11th to 20th	Night	14% 1 11% 40% 28% 6%	552
	21st to end	Night	9% 1 11% 44% 30% 4	624
August	1st to 10th	Night	10% 1 12% 37% 34% 6%	567
	11th to 20th	Night	8% 1 11% 37% 37% 6%	564
	21st to end	Night	12% 15% 38% 30% 5%	641
September	1st to 10th	Night	11% 3 17% 32% 28% 9%	760
	11th to 20th	Night	11% 3 12% 33% 34% 7%	760
	21st to end	Night	18% 3 20% 34% 18% 7%	760
October	1st to 10th	Night	17% 4 22% 32% 19% 5%	760
	11th to 20th	Night	21% 8% 28% 27% 14% 1	760
	21st to end	Night	25% 8% 31% 28% 7%	836
November	1st to 10th	Night	18% 10% 25% 31% 15% 1	764
	11th to 20th	Night	22% 12% 34% 22% 8% 2	760
	21st to end	Night	28% 11% 29% 25% 8%	760
December	1st to 10th	Night	28% 13% 32% 19% 6% 1	760
	11th to 20th	Night	26% 15% 33% 21% 5%	760
	21st to end	Night	32% 10% 30% 25% 3	836

Page generated at 2024-11-03 13:19:04. Version ac07

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