Clarenville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Clarenville clear sky chart from 2005-11-06 to 2026-05-02.

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	18% 14% 5% 10% 6% 5% 5% 4 5% 6% 23%	131566
	Night	18% 13% 5% 10% 5% 5% 4 4 5% 6% 25%	131157
Transparency	Day	60% 7% 11% 15% 6% 1	135033
	Night	59% 7% 11% 16% 7% 1	135803
Seeing	Day	26% 16% 31% 19% 7% 1	20133
	Night	26% 15% 31% 22% 5%	26906

By Month

Percentage Cloud Cover NE (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	20% 17% 7% 12% 5% 4 4 3 5% 5% 19%	4122
	11th to 20th	Day	15% 17% 7% 15% 6% 6% 4 2 3 4 21%	4641
	21st to end	Day	8% 10% 4 13% 7% 5% 5% 4 7% 8% 27%	5157
February	1st to 10th	Day	16% 14% 5% 12% 6% 5% 5% 5% 4 6% 22%	1761
	11th to 20th	Day	18% 14% 4 12% 8% 7% 6% 4 5% 5% 18%	1880
	21st to end	Day	12% 13% 4 11% 8% 7% 5% 4 6% 7% 23%	1730
March	1st to 10th	Day	19% 13% 4 12% 6% 6% 6% 3 4 4 21%	4574
	11th to 20th	Day	19% 16% 8% 10% 6% 5% 5% 4 4 5% 20%	5061
	21st to end	Day	18% 21% 8% 12% 6% 5% 4 3 3 4 15%	5651
April	1st to 10th	Day	18% 17% 6% 10% 7% 5% 5% 3 5% 6% 18%	2536
	11th to 20th	Day	20% 15% 5% 10% 5% 4 4 4 4 6% 23%	2701
	21st to end	Day	23% 19% 5% 10% 6% 4 4 3 4 5% 18%	2730
May	1st to 10th	Day	21% 24% 6% 12% 5% 4 3 2 3 4 16%	5898
	11th to 20th	Day	20% 15% 4 10% 5% 5% 4 3 5% 6% 23%	6488
	21st to end	Day	21% 19% 4 8% 4 4 4 3 5% 6% 21%	7428
June	1st to 10th	Day	29% 14% 4 8% 5% 5% 4 3 4 5% 18%	3000
	11th to 20th	Day	24% 12% 4 8% 6% 5% 4 4 5% 7% 22%	3000
	21st to end	Day	22% 11% 4 9% 6% 5% 5% 4 5% 7% 23%	3000
July	1st to 10th	Day	20% 10% 4 9% 6% 5% 5% 4 6% 7% 22%	6800
	11th to 20th	Day	11% 7% 3 8% 6% 6% 6% 6% 8% 10% 28%	6724
	21st to end	Day	17% 8% 3 8% 6% 5% 5% 4 6% 7% 30%	6927
August	1st to 10th	Day	18% 8% 4 10% 7% 7% 6% 4 6% 7% 23%	4416
	11th to 20th	Day	16% 7% 3 8% 5% 4 6% 4 6% 8% 31%	4176
	21st to end	Day	17% 9% 3 8% 5% 5% 5% 3 6% 8% 31%	4675
September	1st to 10th	Day	17% 9% 3 9% 5% 4 4 4 6% 6% 33%	2392
	11th to 20th	Day	24% 9% 3 7% 5% 4 4 3 5% 7% 29%	2200
	21st to end	Day	17% 10% 4 8% 5% 5% 4 3 5% 7% 32%	2200
October	1st to 10th	Day	19% 11% 3 7% 4 5% 4 4 4 6% 33%	2121
	11th to 20th	Day	22% 15% 3 9% 5% 5% 4 3 5% 5% 25%	1905
	21st to end	Day	23% 13% 4 9% 6% 5% 6% 3 5% 5% 21%	1980
November	1st to 10th	Day	20% 12% 4 8% 5% 5% 5% 4 6% 6% 25%	1836
	11th to 20th	Day	23% 14% 4 9% 6% 4 4 3 4 6% 22%	1680
	21st to end	Day	24% 15% 4 8% 4 5% 4 4 5% 4 22%	1543
December	1st to 10th	Day	14% 13% 3 8% 4 4 6% 5% 7% 8% 28%	2360
	11th to 20th	Day	14% 15% 5% 10% 5% 4 4 3 4 6% 29%	2698
	21st to end	Day	20% 17% 6% 12% 6% 4 4 3 4 5% 19%	3575
January	1st to 10th	Night	18% 17% 7% 12% 6% 5% 5% 3 5% 4 19%	8802
	11th to 20th	Night	14% 14% 7% 13% 6% 5% 5% 4 6% 7% 20%	8258
	21st to end	Night	8% 9% 4 11% 7% 5% 5% 4 6% 7% 34%	9056
February	1st to 10th	Night	16% 13% 4 12% 6% 5% 4 4 5% 6% 26%	2857
	11th to 20th	Night	18% 14% 5% 11% 6% 5% 5% 4 5% 6% 22%	2625
	21st to end	Night	10% 14% 5% 10% 6% 5% 5% 4 5% 6% 29%	2076
March	1st to 10th	Night	19% 11% 4 11% 5% 4 4 4 5% 7% 26%	5486
	11th to 20th	Night	16% 14% 7% 14% 6% 5% 5% 4 6% 6% 17%	5118
	21st to end	Night	19% 18% 5% 13% 6% 5% 5% 3 4 5% 17%	5507
April	1st to 10th	Night	23% 17% 5% 7% 5% 3 3 3 4 5% 25%	2084
	11th to 20th	Night	22% 15% 5% 8% 5% 4 5% 4 4 5% 25%	1868
	21st to end	Night	23% 19% 6% 8% 3 4 3 2 4 6% 23%	1890
May	1st to 10th	Night	23% 18% 8% 10% 5% 5% 4 3 4 5% 16%	4085
	11th to 20th	Night	24% 15% 5% 11% 5% 5% 4 3 4 4 20%	3396
	21st to end	Night	23% 17% 5% 8% 4 4 4 3 5% 6% 22%	3468
June	1st to 10th	Night	27% 13% 5% 8% 5% 5% 5% 3 5% 4 20%	1400
	11th to 20th	Night	24% 11% 4 8% 6% 5% 4 4 4 7% 23%	1400
	21st to end	Night	21% 12% 3 8% 6% 4 5% 5% 5% 8% 23%	1400
July	1st to 10th	Night	22% 10% 4 10% 5% 4 4 4 6% 8% 23%	3179
	11th to 20th	Night	11% 6% 3 8% 6% 6% 7% 5% 7% 10% 30%	3240
	21st to end	Night	15% 8% 3 8% 6% 5% 5% 4 6% 7% 33%	3948
August	1st to 10th	Night	14% 7% 3 7% 5% 5% 6% 5% 8% 9% 31%	2742
	11th to 20th	Night	21% 8% 2 5% 3 3 3 3 5% 7% 39%	2881
	21st to end	Night	22% 7% 3 7% 4 4 4 3 5% 7% 35%	3234
September	1st to 10th	Night	18% 9% 2 7% 3 5% 4 3 6% 8% 34%	2003
	11th to 20th	Night	22% 10% 2 7% 4 5% 5% 4 5% 6% 30%	2200
	21st to end	Night	19% 12% 3 6% 4 5% 4 3 6% 7% 33%	2200
October	1st to 10th	Night	20% 11% 4 7% 4 4 4 3 5% 7% 31%	2278
	11th to 20th	Night	21% 14% 3 7% 5% 4 4 4 5% 7% 27%	2494
	21st to end	Night	22% 14% 3 8% 5% 4 5% 3 4 6% 26%	2860
November	1st to 10th	Night	20% 13% 4 8% 5% 5% 5% 4 5% 6% 25%	2679
	11th to 20th	Night	25% 13% 4 8% 6% 4 4 3 4 6% 23%	2940
	21st to end	Night	20% 17% 4 8% 4 4 5% 4 5% 6% 24%	3077
December	1st to 10th	Night	16% 14% 4 8% 5% 4 4 3 5% 6% 31%	5050
	11th to 20th	Night	16% 14% 5% 11% 6% 5% 4 3 4 5% 26%	5731
	21st to end	Night	19% 15% 6% 10% 5% 5% 4 3 4 5% 23%	7645

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	67% 6% 8% 12% 5% 1	4123
	11th to 20th	Day	68% 5% 6% 13% 8% 1	4670
	21st to end	Day	54% 5% 8% 18% 12% 2	5157
February	1st to 10th	Day	63% 6% 11% 11% 9% 1	1761
	11th to 20th	Day	66% 8% 8% 11% 6% 1	1887
	21st to end	Day	60% 7% 9% 12% 9% 2	1730
March	1st to 10th	Day	64% 5% 7% 12% 10% 2	4578
	11th to 20th	Day	67% 6% 8% 10% 7% 1	5061
	21st to end	Day	73% 6% 6% 9% 5% 1	5651
April	1st to 10th	Day	67% 7% 7% 12% 6% 1	2536
	11th to 20th	Day	63% 6% 8% 14% 8% 1	2701
	21st to end	Day	68% 6% 8% 10% 7% 1	2730
May	1st to 10th	Day	72% 6% 7% 11% 4 1	5910
	11th to 20th	Day	61% 6% 12% 15% 5%	6492
	21st to end	Day	64% 7% 10% 16% 3	7428
June	1st to 10th	Day	69% 7% 7% 12% 4	3000
	11th to 20th	Day	61% 7% 12% 14% 5% 1	3000
	21st to end	Day	61% 8% 11% 14% 6%	3000
July	1st to 10th	Day	58% 9% 13% 16% 4	6725
	11th to 20th	Day	48% 10% 20% 16% 6%	6642
	21st to end	Day	51% 7% 17% 21% 4	6730
August	1st to 10th	Day	57% 10% 13% 16% 4	4402
	11th to 20th	Day	49% 9% 15% 23% 4	4215
	21st to end	Day	50% 7% 16% 24% 4	4675
September	1st to 10th	Day	50% 7% 12% 21% 8% 1	2392
	11th to 20th	Day	54% 7% 12% 18% 8% 1	2200
	21st to end	Day	51% 6% 16% 19% 8%	2200
October	1st to 10th	Day	60% 7% 9% 18% 5%	3463
	11th to 20th	Day	53% 5% 15% 19% 8%	3092
	21st to end	Day	61% 6% 9% 18% 6% 1	3191
November	1st to 10th	Day	59% 8% 14% 12% 6% 1	1836
	11th to 20th	Day	63% 7% 10% 14% 6% 1	1680
	21st to end	Day	66% 7% 9% 11% 6% 1	1543
December	1st to 10th	Day	55% 6% 12% 20% 7%	2360
	11th to 20th	Day	58% 5% 16% 12% 8%	2697
	21st to end	Day	67% 6% 9% 13% 5%	3575
January	1st to 10th	Night	69% 5% 7% 10% 7% 2	8802
	11th to 20th	Night	62% 6% 11% 14% 5%	8304
	21st to end	Night	50% 5% 10% 16% 14% 3	9056
February	1st to 10th	Night	61% 5% 11% 13% 8% 2	2857
	11th to 20th	Night	63% 7% 10% 14% 6% 1	2629
	21st to end	Night	56% 5% 11% 15% 11% 1	2076
March	1st to 10th	Night	58% 5% 9% 16% 11% 1	5495
	11th to 20th	Night	66% 8% 9% 9% 6% 1	5119
	21st to end	Night	69% 6% 8% 13% 4 1	5507
April	1st to 10th	Night	63% 6% 7% 12% 10% 1	2084
	11th to 20th	Night	62% 4 9% 17% 6% 1	1868
	21st to end	Night	66% 5% 7% 13% 8% 1	1890
May	1st to 10th	Night	70% 7% 8% 12% 2	4090
	11th to 20th	Night	68% 6% 9% 12% 6%	3397
	21st to end	Night	64% 7% 11% 14% 3	3469
June	1st to 10th	Night	65% 9% 10% 11% 5%	1400
	11th to 20th	Night	61% 7% 12% 14% 5%	1400
	21st to end	Night	59% 10% 12% 13% 6%	1400
July	1st to 10th	Night	60% 7% 14% 16% 3	3146
	11th to 20th	Night	45% 13% 17% 21% 4	3198
	21st to end	Night	50% 8% 15% 24% 2	3831
August	1st to 10th	Night	45% 13% 19% 18% 4	2731
	11th to 20th	Night	46% 7% 15% 27% 5%	2908
	21st to end	Night	49% 7% 15% 24% 5%	3233
September	1st to 10th	Night	48% 7% 15% 20% 9%	2003
	11th to 20th	Night	54% 7% 14% 14% 9% 1	2200
	21st to end	Night	50% 7% 14% 20% 8% 1	2200
October	1st to 10th	Night	58% 6% 15% 16% 5%	3720
	11th to 20th	Night	49% 6% 17% 19% 9%	4056
	21st to end	Night	54% 5% 12% 20% 8%	4610
November	1st to 10th	Night	59% 7% 14% 15% 5%	2679
	11th to 20th	Night	62% 7% 10% 15% 5% 1	2940
	21st to end	Night	59% 8% 12% 14% 7% 1	3077
December	1st to 10th	Night	55% 5% 9% 21% 10%	5050
	11th to 20th	Night	61% 6% 15% 13% 6%	5733
	21st to end	Night	63% 6% 9% 15% 6%	7645

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	29% 19% 30% 18% 3 1	430
	11th to 20th	Day	25% 20% 32% 17% 5% 1	430
	21st to end	Day	22% 24% 34% 16% 4	473
February	1st to 10th	Day	25% 22% 29% 19% 5% 1	430
	11th to 20th	Day	25% 25% 33% 13% 4 1	426
	21st to end	Day	21% 21% 39% 15% 4 1	355
March	1st to 10th	Day	26% 28% 29% 13% 4	430
	11th to 20th	Day	25% 24% 28% 14% 7% 2	430
	21st to end	Day	27% 21% 32% 14% 4 2	487
April	1st to 10th	Day	30% 22% 31% 13% 4 1	556
	11th to 20th	Day	29% 17% 32% 17% 6%	739
	21st to end	Day	32% 15% 28% 18% 6% 1	750
May	1st to 10th	Day	30% 18% 28% 16% 5% 3	708
	11th to 20th	Day	24% 14% 32% 19% 8% 2	724
	21st to end	Day	26% 15% 32% 20% 5% 2	790
June	1st to 10th	Day	36% 12% 26% 18% 7% 1	730
	11th to 20th	Day	30% 14% 26% 21% 7% 2	730
	21st to end	Day	27% 11% 31% 21% 8% 2	730
July	1st to 10th	Day	25% 12% 31% 22% 8% 2	720
	11th to 20th	Day	18% 9% 38% 25% 10% 1	718
	21st to end	Day	23% 12% 31% 24% 9%	795
August	1st to 10th	Day	22% 9% 30% 27% 10% 2	725
	11th to 20th	Day	22% 10% 27% 28% 11% 2	717
	21st to end	Day	20% 13% 31% 23% 12% 2	803
September	1st to 10th	Day	18% 11% 31% 28% 11% 2	547
	11th to 20th	Day	30% 14% 29% 21% 6% 1	420
	21st to end	Day	23% 14% 35% 20% 5% 2	420
October	1st to 10th	Day	19% 15% 36% 23% 6% 1	420
	11th to 20th	Day	31% 15% 28% 17% 5% 3	420
	21st to end	Day	23% 23% 31% 14% 8% 2	462
November	1st to 10th	Day	30% 20% 29% 15% 5% 1	425
	11th to 20th	Day	34% 16% 27% 16% 6%	430
	21st to end	Day	34% 21% 27% 12% 5%	430
December	1st to 10th	Day	28% 18% 32% 17% 5%	430
	11th to 20th	Day	28% 26% 31% 12% 3	430
	21st to end	Day	26% 18% 33% 16% 7% 1	473
January	1st to 10th	Night	27% 18% 33% 19% 3 1	950
	11th to 20th	Night	26% 21% 32% 17% 4	950
	21st to end	Night	23% 19% 36% 20% 2	1045
February	1st to 10th	Night	25% 19% 35% 17% 4	950
	11th to 20th	Night	28% 22% 33% 13% 4	913
	21st to end	Night	18% 18% 36% 22% 5% 1	692
March	1st to 10th	Night	26% 19% 35% 16% 5%	840
	11th to 20th	Night	20% 19% 30% 22% 8% 1	646
	21st to end	Night	30% 15% 29% 22% 3	693
April	1st to 10th	Night	29% 18% 32% 16% 4	630
	11th to 20th	Night	27% 15% 34% 19% 5%	624
	21st to end	Night	32% 11% 31% 20% 5%	630
May	1st to 10th	Night	30% 11% 30% 23% 5% 1	604
	11th to 20th	Night	31% 9% 27% 24% 8%	592
	21st to end	Night	29% 12% 32% 21% 6%	649
June	1st to 10th	Night	33% 13% 28% 22% 5% 1	600
	11th to 20th	Night	27% 10% 30% 27% 6%	600
	21st to end	Night	26% 11% 32% 23% 8% 1	600
July	1st to 10th	Night	23% 8% 35% 27% 7% 1	586
	11th to 20th	Night	21% 10% 36% 29% 5%	582
	21st to end	Night	24% 8% 35% 28% 5%	656
August	1st to 10th	Night	23% 6% 29% 31% 10% 1	598
	11th to 20th	Night	24% 8% 27% 33% 8%	592
	21st to end	Night	22% 9% 28% 31% 10%	660
September	1st to 10th	Night	20% 11% 31% 28% 10%	600
	11th to 20th	Night	26% 11% 29% 30% 4	600
	21st to end	Night	26% 13% 30% 25% 5% 1	600
October	1st to 10th	Night	23% 12% 32% 25% 6%	644
	11th to 20th	Night	30% 14% 29% 20% 7%	804
	21st to end	Night	28% 14% 30% 22% 6%	1001
November	1st to 10th	Night	28% 18% 30% 19% 4	930
	11th to 20th	Night	32% 17% 26% 19% 5%	950
	21st to end	Night	28% 21% 32% 16% 4	950
December	1st to 10th	Night	27% 17% 30% 19% 5%	950
	11th to 20th	Night	32% 21% 29% 15% 3	950
	21st to end	Night	24% 15% 34% 20% 5% 1	1045

Page generated at 2026-04-29 03:21:44. Version ac07

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