Bucksport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bucksport clear sky chart from 2005-11-06 to 2026-08-15.

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	17% 9% 3 7% 4 4 4 4 5% 7% 37%	143182
	Night	18% 9% 3 7% 4 4 4 3 5% 6% 36%	138752
Transparency	Day	46% 5% 12% 22% 13% 2	146705
	Night	47% 5% 11% 22% 14% 2	143319
Seeing	Day	26% 17% 31% 17% 6% 2	18069
	Night	25% 15% 29% 24% 7% 1	26327

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	14% 10% 3 9% 5% 5% 5% 4 5% 5% 36%	4661
	11th to 20th	Day	16% 11% 3 6% 4 4 4 3 4 5% 39%	4650
	21st to end	Day	10% 9% 3 7% 4 4 4 3 4 5% 45%	5221
February	1st to 10th	Day	15% 10% 3 7% 4 4 4 4 5% 6% 36%	1890
	11th to 20th	Day	13% 9% 3 7% 5% 5% 5% 4 6% 5% 37%	1958
	21st to end	Day	13% 11% 3 8% 6% 4 5% 4 5% 5% 37%	1730
March	1st to 10th	Day	24% 12% 3 8% 5% 4 4 3 4 5% 29%	4614
	11th to 20th	Day	18% 13% 3 7% 4 4 5% 3 4 7% 32%	5090
	21st to end	Day	28% 9% 3 7% 4 4 3 3 5% 6% 29%	5587
April	1st to 10th	Day	21% 11% 3 8% 5% 3 3 3 4 6% 32%	2498
	11th to 20th	Day	20% 9% 2 7% 4 4 4 3 5% 6% 37%	2676
	21st to end	Day	22% 10% 3 6% 4 4 4 2 5% 5% 35%	2730
May	1st to 10th	Day	27% 10% 3 8% 4 4 4 3 4 6% 26%	7639
	11th to 20th	Day	17% 9% 3 8% 5% 5% 5% 4 6% 7% 34%	7625
	21st to end	Day	17% 8% 3 7% 4 5% 5% 4 6% 7% 33%	9267
June	1st to 10th	Day	21% 7% 3 8% 5% 4 4 3 5% 7% 31%	3150
	11th to 20th	Day	18% 7% 3 6% 4 4 4 4 6% 8% 36%	3150
	21st to end	Day	24% 8% 2 6% 6% 4 5% 4 5% 7% 30%	3150
July	1st to 10th	Day	13% 7% 3 7% 5% 5% 5% 5% 7% 10% 33%	8522
	11th to 20th	Day	12% 7% 3 6% 4 5% 5% 4 6% 9% 41%	8280
	21st to end	Day	15% 6% 2 5% 4 4 4 4 6% 8% 43%	8862
August	1st to 10th	Day	17% 7% 2 6% 5% 5% 5% 4 6% 8% 35%	4365
	11th to 20th	Day	16% 8% 3 7% 5% 4 5% 4 6% 7% 34%	4227
	21st to end	Day	11% 5% 2 6% 4 5% 4 3 6% 8% 46%	4652
September	1st to 10th	Day	12% 5% 1 5% 4 3 4 3 5% 8% 50%	2300
	11th to 20th	Day	13% 5% 2 4 4 4 4 3 4 5% 52%	2200
	21st to end	Day	17% 6% 2 5% 3 4 3 3 5% 7% 44%	2200
October	1st to 10th	Day	17% 6% 2 6% 4 4 4 3 5% 6% 42%	2145
	11th to 20th	Day	19% 6% 2 6% 4 4 4 3 5% 6% 41%	1985
	21st to end	Day	22% 9% 3 6% 4 3 3 3 4 6% 36%	1980
November	1st to 10th	Day	18% 7% 2 5% 5% 5% 4 3 6% 6% 39%	1851
	11th to 20th	Day	19% 7% 2 5% 4 3 4 4 5% 6% 42%	1853
	21st to end	Day	21% 9% 2 5% 3 3 4 3 3 6% 40%	1680
December	1st to 10th	Day	16% 12% 2 5% 2 3 4 3 4 7% 41%	2491
	11th to 20th	Day	20% 9% 2 5% 3 3 4 2 4 5% 44%	2688
	21st to end	Day	21% 11% 3 5% 3 3 5% 3 5% 5% 35%	3615
January	1st to 10th	Night	12% 10% 4 9% 5% 4 4 3 5% 6% 38%	8234
	11th to 20th	Night	16% 12% 4 9% 6% 5% 4 4 5% 6% 30%	8235
	21st to end	Night	11% 11% 3 7% 4 4 5% 4 5% 7% 40%	8959
February	1st to 10th	Night	15% 10% 4 7% 5% 5% 5% 4 4 6% 35%	2730
	11th to 20th	Night	13% 9% 3 8% 5% 5% 5% 4 5% 5% 39%	2544
	21st to end	Night	14% 11% 3 7% 5% 4 4 3 5% 5% 38%	2076
March	1st to 10th	Night	26% 11% 3 7% 4 4 3 3 4 5% 29%	5445
	11th to 20th	Night	18% 11% 4 8% 4 5% 4 5% 5% 7% 30%	5089
	21st to end	Night	26% 9% 2 6% 5% 4 5% 3 6% 6% 28%	5587
April	1st to 10th	Night	21% 13% 4 7% 4 4 3 3 4 4 33%	2120
	11th to 20th	Night	20% 9% 3 8% 3 5% 4 4 6% 7% 33%	1893
	21st to end	Night	24% 8% 2 7% 4 3 3 3 5% 6% 34%	1890
May	1st to 10th	Night	30% 9% 3 6% 3 3 3 3 4 6% 29%	5259
	11th to 20th	Night	21% 9% 3 7% 4 4 4 4 5% 7% 33%	5235
	21st to end	Night	14% 9% 3 8% 5% 5% 4 4 6% 7% 36%	4974
June	1st to 10th	Night	21% 9% 2 7% 5% 4 4 3 6% 8% 31%	1470
	11th to 20th	Night	16% 8% 3 7% 3 4 4 3 6% 7% 37%	1470
	21st to end	Night	23% 10% 2 7% 4 4 4 5% 5% 6% 30%	1470
July	1st to 10th	Night	12% 8% 4 8% 6% 5% 6% 4 7% 9% 31%	4445
	11th to 20th	Night	15% 8% 2 6% 4 5% 5% 4 5% 8% 38%	4680
	21st to end	Night	14% 6% 2 5% 3 4 4 4 6% 8% 43%	5143
August	1st to 10th	Night	20% 8% 3 7% 5% 5% 5% 4 5% 7% 31%	3005
	11th to 20th	Night	17% 10% 3 7% 5% 4 4 4 6% 8% 31%	2909
	21st to end	Night	10% 7% 3 7% 4 4 5% 3 7% 8% 43%	3241
September	1st to 10th	Night	14% 5% 2 4 3 3 4 5% 5% 7% 49%	2099
	11th to 20th	Night	15% 6% 2 4 2 2 3 3 5% 7% 51%	2200
	21st to end	Night	17% 7% 2 5% 4 3 4 3 5% 7% 44%	2200
October	1st to 10th	Night	17% 6% 2 7% 4 4 5% 3 5% 5% 43%	2255
	11th to 20th	Night	18% 6% 2 6% 4 4 4 3 4 7% 41%	2413
	21st to end	Night	23% 9% 2 6% 4 4 4 3 4 6% 36%	2860
November	1st to 10th	Night	19% 6% 2 6% 5% 4 3 3 4 5% 42%	2667
	11th to 20th	Night	18% 6% 2 6% 5% 5% 4 3 5% 6% 40%	2764
	21st to end	Night	19% 9% 3 5% 3 4 4 3 5% 6% 38%	2940
December	1st to 10th	Night	18% 9% 3 6% 4 4 4 3 6% 7% 37%	4914
	11th to 20th	Night	23% 9% 2 5% 3 3 3 2 4 5% 42%	5741
	21st to end	Night	22% 10% 3 6% 3 4 3 3 4 6% 37%	7596

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	49% 3 12% 24% 11% 1	4662
	11th to 20th	Day	47% 3 11% 25% 12% 2	4680
	21st to end	Day	41% 3 10% 21% 19% 5%	5221
February	1st to 10th	Day	48% 4 11% 20% 14% 3	1890
	11th to 20th	Day	46% 5% 12% 21% 14% 2	1966
	21st to end	Day	48% 5% 11% 20% 12% 5%	1730
March	1st to 10th	Day	59% 3 8% 10% 15% 5%	4617
	11th to 20th	Day	51% 6% 14% 17% 10% 2	5090
	21st to end	Day	55% 4 5% 17% 15% 3	5587
April	1st to 10th	Day	53% 4 9% 16% 15% 4	2498
	11th to 20th	Day	48% 4 9% 22% 14% 3	2676
	21st to end	Day	51% 3 8% 19% 15% 4	2730
May	1st to 10th	Day	58% 5% 12% 16% 8% 1	7651
	11th to 20th	Day	48% 6% 14% 20% 9% 2	7629
	21st to end	Day	47% 8% 12% 20% 13% 1	9268
June	1st to 10th	Day	51% 6% 12% 20% 10% 1	3150
	11th to 20th	Day	46% 6% 11% 20% 15% 2	3150
	21st to end	Day	52% 7% 11% 19% 9% 2	3150
July	1st to 10th	Day	45% 6% 14% 25% 10%	8452
	11th to 20th	Day	39% 5% 14% 23% 17% 1	8205
	21st to end	Day	39% 5% 12% 29% 14% 1	8666
August	1st to 10th	Day	46% 7% 14% 26% 6%	4352
	11th to 20th	Day	47% 6% 17% 21% 9%	4266
	21st to end	Day	34% 5% 14% 27% 19% 1	4652
September	1st to 10th	Day	33% 6% 14% 28% 18% 1	2300
	11th to 20th	Day	34% 5% 9% 28% 21% 3	2200
	21st to end	Day	39% 6% 10% 26% 17% 1	2200
October	1st to 10th	Day	49% 6% 9% 22% 12% 1	3496
	11th to 20th	Day	36% 3 10% 32% 19%	3213
	21st to end	Day	37% 3 16% 24% 18% 2	3180
November	1st to 10th	Day	44% 5% 13% 22% 15% 1	1851
	11th to 20th	Day	43% 4 10% 23% 17% 3	1853
	21st to end	Day	47% 5% 14% 23% 10% 1	1680
December	1st to 10th	Day	43% 4 16% 23% 13% 1	2491
	11th to 20th	Day	45% 3 13% 17% 16% 6%	2688
	21st to end	Day	50% 4 10% 20% 12% 3	3615
January	1st to 10th	Night	47% 3 12% 24% 13% 1	8234
	11th to 20th	Night	55% 4 11% 18% 11% 2	8280
	21st to end	Night	44% 3 8% 23% 17% 5%	8959
February	1st to 10th	Night	51% 4 11% 20% 13% 2	2730
	11th to 20th	Night	47% 5% 9% 21% 16% 2	2547
	21st to end	Night	47% 4 9% 20% 16% 4	2076
March	1st to 10th	Night	58% 2 7% 13% 14% 7%	5455
	11th to 20th	Night	51% 6% 17% 16% 7% 1	5090
	21st to end	Night	55% 4 5% 17% 17% 2	5587
April	1st to 10th	Night	54% 4 7% 15% 17% 3	2120
	11th to 20th	Night	49% 4 9% 21% 14% 2	1893
	21st to end	Night	51% 3 10% 18% 14% 3	1890
May	1st to 10th	Night	57% 4 13% 15% 11%	5265
	11th to 20th	Night	49% 7% 12% 22% 8% 1	5236
	21st to end	Night	47% 7% 11% 23% 12%	4975
June	1st to 10th	Night	51% 5% 11% 22% 9% 1	1470
	11th to 20th	Night	44% 7% 13% 21% 12% 2	1470
	21st to end	Night	54% 6% 10% 19% 9% 2	1470
July	1st to 10th	Night	50% 6% 11% 24% 8%	4405
	11th to 20th	Night	45% 6% 11% 25% 12%	4632
	21st to end	Night	39% 6% 14% 30% 11% 1	5025
August	1st to 10th	Night	53% 6% 12% 20% 7%	2993
	11th to 20th	Night	50% 7% 14% 20% 9%	2936
	21st to end	Night	37% 7% 13% 24% 18% 1	3241
September	1st to 10th	Night	34% 5% 13% 30% 17% 1	2099
	11th to 20th	Night	34% 5% 11% 29% 20% 2	2200
	21st to end	Night	40% 6% 9% 28% 16% 1	2200
October	1st to 10th	Night	41% 5% 14% 24% 14% 1	3684
	11th to 20th	Night	35% 4 9% 30% 21% 1	3924
	21st to end	Night	39% 3 12% 28% 15% 2	4610
November	1st to 10th	Night	44% 5% 11% 24% 15% 1	2667
	11th to 20th	Night	44% 5% 10% 23% 17% 2	2764
	21st to end	Night	45% 5% 14% 20% 14% 2	2940
December	1st to 10th	Night	47% 4 9% 27% 13%	4914
	11th to 20th	Night	46% 3 11% 20% 18% 2	5742
	21st to end	Night	49% 4 11% 17% 17% 2	7596

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	33% 23% 27% 14% 4	220
	11th to 20th	Day	36% 20% 28% 12% 3	220
	21st to end	Day	26% 26% 31% 15% 2	274
February	1st to 10th	Day	28% 20% 31% 17% 4	430
	11th to 20th	Day	29% 27% 31% 10% 2	487
	21st to end	Day	26% 24% 33% 12% 4	446
March	1st to 10th	Day	33% 23% 29% 14% 1	540
	11th to 20th	Day	30% 26% 28% 13% 2 1	540
	21st to end	Day	35% 21% 27% 12% 4 2	594
April	1st to 10th	Day	37% 22% 27% 9% 4 1	540
	11th to 20th	Day	35% 24% 26% 10% 4 1	532
	21st to end	Day	30% 23% 31% 13% 2 1	540
May	1st to 10th	Day	34% 20% 30% 12% 3 1	543
	11th to 20th	Day	25% 19% 35% 16% 4 1	567
	21st to end	Day	24% 19% 33% 18% 5% 1	709
June	1st to 10th	Day	25% 14% 31% 20% 9% 2	780
	11th to 20th	Day	24% 15% 30% 20% 10% 1	780
	21st to end	Day	27% 13% 28% 23% 7% 1	780
July	1st to 10th	Day	22% 13% 34% 21% 9% 1	651
	11th to 20th	Day	21% 13% 36% 21% 8% 1	564
	21st to end	Day	18% 11% 39% 21% 8% 3	620
August	1st to 10th	Day	17% 10% 33% 28% 9% 2	566
	11th to 20th	Day	19% 12% 28% 26% 12% 3	535
	21st to end	Day	18% 11% 33% 25% 10% 3	583
September	1st to 10th	Day	16% 11% 39% 22% 9% 3	530
	11th to 20th	Day	21% 11% 29% 21% 12% 7%	530
	21st to end	Day	18% 15% 32% 19% 10% 5%	530
October	1st to 10th	Day	21% 16% 27% 21% 13% 3	500
	11th to 20th	Day	27% 15% 30% 18% 7% 3	420
	21st to end	Day	34% 15% 29% 16% 5% 1	462
November	1st to 10th	Day	27% 18% 28% 19% 6% 1	425
	11th to 20th	Day	29% 17% 35% 14% 4 1	430
	21st to end	Day	33% 21% 25% 17% 4	430
December	1st to 10th	Day	29% 18% 32% 16% 4	309
	11th to 20th	Day	38% 25% 27% 9% 2	220
	21st to end	Day	39% 18% 25% 14% 3	242
January	1st to 10th	Night	27% 21% 31% 18% 4	840
	11th to 20th	Night	31% 19% 30% 17% 3	840
	21st to end	Night	21% 23% 33% 19% 4	924
February	1st to 10th	Night	25% 22% 28% 22% 3	840
	11th to 20th	Night	24% 21% 35% 16% 3	823
	21st to end	Night	26% 18% 33% 21% 3	692
March	1st to 10th	Night	28% 18% 34% 18% 2	840
	11th to 20th	Night	25% 20% 31% 19% 5%	840
	21st to end	Night	27% 18% 30% 20% 5% 1	924
April	1st to 10th	Night	32% 18% 32% 15% 2	840
	11th to 20th	Night	26% 17% 32% 21% 5%	649
	21st to end	Night	30% 14% 29% 22% 5%	630
May	1st to 10th	Night	28% 10% 34% 23% 5%	630
	11th to 20th	Night	27% 12% 33% 23% 5%	622
	21st to end	Night	22% 11% 32% 26% 8%	499
June	1st to 10th	Night	25% 10% 25% 32% 8%	420
	11th to 20th	Night	20% 9% 26% 34% 10%	420
	21st to end	Night	28% 9% 21% 35% 8%	420
July	1st to 10th	Night	20% 6% 26% 37% 10%	410
	11th to 20th	Night	21% 4 22% 40% 12% 1	408
	21st to end	Night	21% 6% 21% 38% 14% 1	481
August	1st to 10th	Night	18% 5% 25% 39% 12% 1	628
	11th to 20th	Night	19% 7% 25% 35% 13% 1	605
	21st to end	Night	18% 7% 24% 35% 15% 1	665
September	1st to 10th	Night	17% 6% 31% 30% 15% 1	800
	11th to 20th	Night	19% 9% 24% 28% 17% 4	800
	21st to end	Night	20% 10% 27% 28% 13% 2	800
October	1st to 10th	Night	22% 10% 23% 28% 16% 1	800
	11th to 20th	Night	22% 14% 28% 25% 10% 2	800
	21st to end	Night	30% 16% 27% 22% 5%	880
November	1st to 10th	Night	26% 15% 29% 23% 7% 1	820
	11th to 20th	Night	26% 17% 29% 20% 7% 1	859
	21st to end	Night	29% 19% 27% 19% 5%	950
December	1st to 10th	Night	29% 16% 32% 18% 5%	950
	11th to 20th	Night	29% 23% 29% 16% 3	950
	21st to end	Night	29% 21% 28% 19% 3	1028

Page generated at 2026-08-12 03:37:18. Version ac07

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