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 2025-04-11.

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% 8% 3 6% 4 4 4 3 5% 7% 36%	112694
	Night	18% 9% 3 7% 4 4 4 3 5% 6% 36%	115618
Transparency	Day	46% 5% 12% 21% 13% 2	116263
	Night	47% 5% 11% 21% 14% 2	120214
Seeing	Day	27% 17% 31% 18% 6% 1	16214
	Night	25% 15% 29% 24% 7% 1	24729

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	15% 9% 3 9% 5% 5% 5% 3 4 5% 36%	3597
	11th to 20th	Day	14% 9% 3 6% 4 5% 4 3 5% 5% 42%	3570
	21st to end	Day	13% 10% 3 8% 4 4 4 3 4 5% 43%	4029
February	1st to 10th	Day	16% 11% 3 7% 4 4 4 4 5% 6% 35%	1800
	11th to 20th	Day	14% 10% 3 7% 5% 5% 5% 4 5% 5% 36%	1862
	21st to end	Day	13% 11% 3 8% 6% 4 5% 4 5% 5% 36%	1650
March	1st to 10th	Day	24% 12% 3 8% 5% 4 4 3 4 5% 29%	4513
	11th to 20th	Day	18% 13% 3 7% 4 4 5% 3 4 6% 32%	4980
	21st to end	Day	28% 9% 3 7% 4 4 3 3 5% 6% 29%	5466
April	1st to 10th	Day	21% 11% 3 8% 5% 3 3 3 4 5% 33%	2379
	11th to 20th	Day	19% 9% 2 6% 4 4 4 3 5% 7% 38%	2418
	21st to end	Day	21% 10% 3 7% 4 4 4 2 5% 5% 35%	2470
May	1st to 10th	Day	21% 9% 3 7% 4 4 4 4 6% 7% 31%	4106
	11th to 20th	Day	18% 9% 3 7% 4 4 5% 4 6% 7% 32%	4081
	21st to end	Day	16% 7% 2 6% 5% 5% 5% 4 6% 8% 35%	4946
June	1st to 10th	Day	22% 8% 3 8% 5% 4 4 3 5% 7% 30%	2850
	11th to 20th	Day	18% 7% 3 6% 4 4 4 4 6% 7% 36%	2850
	21st to end	Day	24% 8% 2 6% 6% 5% 4 4 5% 7% 29%	2850
July	1st to 10th	Day	15% 6% 3 7% 5% 5% 5% 4 6% 9% 35%	4570
	11th to 20th	Day	15% 7% 2 5% 4 4 4 4 7% 11% 37%	4440
	21st to end	Day	19% 7% 3 6% 4 4 4 4 6% 7% 36%	4739
August	1st to 10th	Day	18% 8% 2 6% 5% 5% 5% 4 6% 8% 33%	4105
	11th to 20th	Day	17% 9% 3 7% 5% 4 5% 4 6% 7% 33%	4045
	21st to end	Day	10% 5% 2 6% 4 5% 4 3 6% 8% 46%	4510
September	1st to 10th	Day	12% 5% 2 5% 4 3 4 3 5% 8% 50%	2185
	11th to 20th	Day	14% 4 2 4 4 4 3 3 4 5% 52%	2090
	21st to end	Day	17% 6% 2 5% 3 4 4 3 5% 7% 43%	2090
October	1st to 10th	Day	18% 6% 2 7% 4 4 5% 3 5% 7% 40%	2038
	11th to 20th	Day	19% 6% 2 6% 4 5% 4 3 5% 6% 41%	1886
	21st to end	Day	22% 9% 3 6% 4 3 3 3 4 6% 36%	1881
November	1st to 10th	Day	18% 7% 2 5% 4 5% 4 3 6% 6% 40%	1761
	11th to 20th	Day	20% 7% 2 5% 4 3 4 4 5% 6% 41%	1765
	21st to end	Day	21% 9% 2 5% 3 3 3 3 3 6% 41%	1600
December	1st to 10th	Day	16% 12% 2 5% 2 3 4 3 5% 7% 40%	2417
	11th to 20th	Day	20% 9% 2 5% 3 3 4 2 4 5% 43%	2618
	21st to end	Day	21% 11% 3 5% 3 3 5% 3 5% 5% 35%	3537
January	1st to 10th	Night	13% 9% 3 9% 5% 4 4 3 5% 6% 39%	6349
	11th to 20th	Night	14% 10% 4 8% 6% 5% 5% 4 5% 6% 33%	6315
	21st to end	Night	12% 11% 3 8% 4 4 4 4 5% 6% 39%	6926
February	1st to 10th	Night	16% 10% 4 6% 6% 5% 5% 4 4 6% 34%	2600
	11th to 20th	Night	13% 9% 3 9% 5% 5% 5% 4 4 5% 38%	2420
	21st to end	Night	14% 12% 3 7% 6% 4 4 3 5% 5% 38%	1980
March	1st to 10th	Night	27% 11% 3 7% 4 4 3 3 4 5% 29%	5326
	11th to 20th	Night	17% 11% 4 8% 4 5% 4 5% 5% 7% 30%	4979
	21st to end	Night	26% 9% 2 6% 5% 4 5% 3 5% 6% 28%	5466
April	1st to 10th	Night	22% 13% 3 7% 4 4 3 3 5% 5% 33%	2019
	11th to 20th	Night	19% 8% 2 8% 3 5% 4 4 6% 7% 34%	1718
	21st to end	Night	24% 8% 2 7% 4 3 3 3 5% 6% 34%	1710
May	1st to 10th	Night	24% 8% 3 5% 3 4 4 3 5% 8% 33%	2834
	11th to 20th	Night	18% 7% 3 8% 5% 5% 6% 4 6% 9% 29%	2813
	21st to end	Night	14% 7% 3 7% 5% 5% 5% 4 6% 7% 37%	2659
June	1st to 10th	Night	22% 9% 2 8% 4 4 4 3 6% 7% 30%	1330
	11th to 20th	Night	17% 8% 4 7% 3 4 5% 4 6% 7% 37%	1330
	21st to end	Night	24% 11% 2 7% 4 4 4 5% 5% 5% 29%	1330
July	1st to 10th	Night	15% 7% 3 6% 6% 6% 7% 4 7% 9% 30%	2389
	11th to 20th	Night	17% 7% 2 7% 5% 5% 5% 4 5% 8% 35%	2520
	21st to end	Night	16% 7% 2 6% 3 4 4 4 6% 8% 38%	2770
August	1st to 10th	Night	21% 8% 3 7% 5% 5% 5% 4 5% 7% 29%	2825
	11th to 20th	Night	18% 10% 3 7% 5% 4 5% 4 6% 8% 30%	2782
	21st to end	Night	10% 7% 3 7% 5% 4 5% 3 6% 8% 43%	3142
September	1st to 10th	Night	14% 6% 2 5% 3 3 4 5% 5% 7% 49%	1994
	11th to 20th	Night	16% 6% 2 4 2 2 3 3 5% 7% 50%	2090
	21st to end	Night	18% 7% 2 4 4 3 4 3 5% 7% 43%	2090
October	1st to 10th	Night	18% 6% 2 7% 4 4 5% 3 5% 5% 41%	2142
	11th to 20th	Night	18% 6% 2 6% 4 4 4 3 4 6% 42%	2292
	21st to end	Night	23% 9% 2 5% 4 4 4 3 4 6% 37%	2717
November	1st to 10th	Night	18% 7% 2 6% 5% 4 3 4 4 5% 42%	2537
	11th to 20th	Night	18% 6% 2 6% 5% 5% 4 4 5% 6% 40%	2632
	21st to end	Night	19% 9% 3 5% 3 4 4 3 5% 6% 38%	2800
December	1st to 10th	Night	18% 9% 3 5% 4 4 4 4 6% 7% 37%	4768
	11th to 20th	Night	23% 9% 2 5% 3 2 3 2 4 5% 42%	5591
	21st to end	Night	22% 10% 3 6% 3 4 3 3 4 5% 37%	7433

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	50% 3 12% 25% 10% 1	3598
	11th to 20th	Day	42% 3 13% 28% 11% 2	3600
	21st to end	Day	44% 4 11% 17% 18% 7%	4029
February	1st to 10th	Day	49% 4 11% 18% 14% 3	1800
	11th to 20th	Day	47% 5% 12% 20% 14% 2	1870
	21st to end	Day	49% 5% 10% 20% 11% 5%	1650
March	1st to 10th	Day	59% 3 8% 10% 15% 6%	4516
	11th to 20th	Day	51% 6% 14% 17% 10% 2	4980
	21st to end	Day	55% 4 5% 17% 15% 3	5466
April	1st to 10th	Day	53% 4 8% 16% 15% 4	2379
	11th to 20th	Day	47% 4 10% 23% 15% 2	2418
	21st to end	Day	52% 3 8% 18% 15% 4	2470
May	1st to 10th	Day	50% 7% 13% 19% 10% 2	4120
	11th to 20th	Day	48% 8% 14% 20% 9% 1	4085
	21st to end	Day	42% 11% 15% 18% 14% 1	4946
June	1st to 10th	Day	52% 7% 12% 19% 9% 1	2850
	11th to 20th	Day	46% 6% 11% 19% 15% 2	2850
	21st to end	Day	53% 7% 12% 18% 9% 2	2850
July	1st to 10th	Day	45% 6% 12% 25% 11%	4500
	11th to 20th	Day	40% 7% 16% 25% 11%	4365
	21st to end	Day	46% 7% 11% 22% 13% 1	4588
August	1st to 10th	Day	48% 7% 14% 25% 5%	4092
	11th to 20th	Day	49% 6% 16% 21% 8%	4084
	21st to end	Day	34% 5% 14% 26% 20% 1	4510
September	1st to 10th	Day	33% 6% 15% 27% 18% 1	2185
	11th to 20th	Day	34% 5% 9% 28% 20% 3	2090
	21st to end	Day	40% 6% 10% 27% 17% 1	2090
October	1st to 10th	Day	50% 6% 9% 21% 12% 1	3389
	11th to 20th	Day	35% 3 10% 32% 19%	3114
	21st to end	Day	36% 3 16% 24% 18% 3	3081
November	1st to 10th	Day	43% 5% 13% 22% 15% 1	1761
	11th to 20th	Day	42% 4 10% 23% 18% 3	1765
	21st to end	Day	46% 5% 15% 23% 10% 1	1600
December	1st to 10th	Day	43% 4 16% 23% 13% 1	2417
	11th to 20th	Day	45% 3 13% 17% 16% 7%	2618
	21st to end	Day	50% 4 10% 20% 12% 3	3537
January	1st to 10th	Night	46% 4 12% 26% 11% 1	6349
	11th to 20th	Night	51% 4 13% 21% 9% 2	6360
	21st to end	Night	46% 4 8% 21% 16% 5%	6926
February	1st to 10th	Night	52% 4 11% 18% 13% 2	2600
	11th to 20th	Night	47% 5% 9% 20% 16% 2	2423
	21st to end	Night	47% 4 9% 20% 16% 4	1980
March	1st to 10th	Night	58% 2 7% 13% 13% 7%	5336
	11th to 20th	Night	51% 6% 17% 16% 7% 1	4980
	21st to end	Night	55% 4 5% 17% 17% 2	5466
April	1st to 10th	Night	54% 4 7% 15% 17% 3	2019
	11th to 20th	Night	48% 5% 9% 22% 14% 2	1718
	21st to end	Night	52% 3 11% 17% 14% 3	1710
May	1st to 10th	Night	49% 6% 17% 20% 8% 1	2840
	11th to 20th	Night	49% 10% 16% 18% 7% 1	2814
	21st to end	Night	43% 10% 14% 21% 11% 1	2660
June	1st to 10th	Night	53% 5% 11% 21% 9% 1	1330
	11th to 20th	Night	44% 8% 14% 21% 11% 2	1330
	21st to end	Night	56% 6% 9% 18% 8% 2	1330
July	1st to 10th	Night	49% 8% 12% 19% 12%	2349
	11th to 20th	Night	46% 8% 13% 25% 9%	2472
	21st to end	Night	44% 6% 13% 25% 11% 1	2681
August	1st to 10th	Night	55% 7% 13% 19% 7%	2813
	11th to 20th	Night	51% 7% 14% 19% 10%	2809
	21st to end	Night	37% 7% 13% 24% 18% 1	3142
September	1st to 10th	Night	34% 5% 13% 30% 17% 1	1994
	11th to 20th	Night	35% 5% 11% 29% 19% 2	2090
	21st to end	Night	40% 5% 9% 28% 16% 1	2090
October	1st to 10th	Night	42% 5% 15% 24% 14% 1	3571
	11th to 20th	Night	34% 4 9% 30% 22% 1	3803
	21st to end	Night	39% 3 12% 28% 15% 2	4467
November	1st to 10th	Night	44% 5% 11% 25% 14% 1	2537
	11th to 20th	Night	43% 5% 10% 23% 18% 2	2632
	21st to end	Night	45% 5% 14% 20% 14% 2	2800
December	1st to 10th	Night	47% 4 9% 28% 13%	4768
	11th to 20th	Night	46% 3 11% 20% 18% 2	5592
	21st to end	Night	49% 4 12% 17% 17% 1	7433

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	34% 23% 25% 15% 4	200
	11th to 20th	Day	37% 18% 29% 13% 4 1	200
	21st to end	Day	28% 23% 32% 16% 2	250
February	1st to 10th	Day	29% 21% 31% 16% 4	400
	11th to 20th	Day	31% 28% 31% 9% 2	451
	21st to end	Day	27% 23% 33% 13% 4	414
March	1st to 10th	Day	33% 23% 29% 14% 1	500
	11th to 20th	Day	29% 25% 29% 14% 3 1	500
	21st to end	Day	35% 21% 27% 12% 4 2	550
April	1st to 10th	Day	38% 22% 26% 9% 4 1	500
	11th to 20th	Day	34% 24% 26% 12% 5% 1	452
	21st to end	Day	30% 23% 30% 13% 3 1	460
May	1st to 10th	Day	31% 20% 32% 13% 3 1	463
	11th to 20th	Day	25% 18% 35% 17% 4 1	487
	21st to end	Day	24% 19% 33% 19% 5% 1	612
June	1st to 10th	Day	26% 15% 30% 19% 9% 1	680
	11th to 20th	Day	23% 15% 30% 21% 10% 1	680
	21st to end	Day	28% 14% 27% 23% 8% 1	680
July	1st to 10th	Day	23% 13% 33% 20% 10% 1	563
	11th to 20th	Day	18% 11% 39% 23% 8% 1	484
	21st to end	Day	18% 11% 40% 21% 8% 2	532
August	1st to 10th	Day	18% 11% 33% 27% 9% 2	486
	11th to 20th	Day	20% 12% 28% 26% 11% 3	479
	21st to end	Day	18% 11% 32% 26% 10% 3	539
September	1st to 10th	Day	16% 12% 38% 23% 8% 3	490
	11th to 20th	Day	22% 10% 30% 19% 12% 7%	490
	21st to end	Day	19% 15% 32% 19% 10% 5%	490
October	1st to 10th	Day	21% 16% 27% 21% 12% 2	463
	11th to 20th	Day	27% 14% 30% 18% 7% 3	390
	21st to end	Day	34% 14% 30% 17% 4 1	429
November	1st to 10th	Day	27% 17% 29% 19% 7% 2	395
	11th to 20th	Day	30% 17% 34% 15% 4 1	400
	21st to end	Day	34% 21% 25% 16% 5%	400
December	1st to 10th	Day	29% 18% 32% 16% 4	285
	11th to 20th	Day	38% 25% 26% 10% 2	200
	21st to end	Day	38% 18% 25% 15% 4	220
January	1st to 10th	Night	27% 21% 31% 18% 4	800
	11th to 20th	Night	30% 20% 30% 17% 4	800
	21st to end	Night	21% 23% 33% 19% 4	880
February	1st to 10th	Night	26% 22% 28% 22% 2	800
	11th to 20th	Night	24% 22% 35% 16% 3	783
	21st to end	Night	26% 18% 32% 21% 3	660
March	1st to 10th	Night	28% 19% 33% 19% 2	800
	11th to 20th	Night	24% 20% 31% 20% 6%	800
	21st to end	Night	26% 18% 29% 21% 5% 1	880
April	1st to 10th	Night	32% 17% 31% 16% 3 1	800
	11th to 20th	Night	24% 16% 33% 22% 5%	590
	21st to end	Night	30% 13% 30% 22% 5%	570
May	1st to 10th	Night	28% 9% 34% 23% 6%	570
	11th to 20th	Night	26% 12% 33% 24% 5% 1	562
	21st to end	Night	22% 10% 32% 27% 8%	451
June	1st to 10th	Night	26% 11% 25% 31% 8% 1	380
	11th to 20th	Night	21% 9% 26% 34% 11%	380
	21st to end	Night	29% 8% 21% 35% 7%	380
July	1st to 10th	Night	21% 6% 26% 36% 11%	370
	11th to 20th	Night	21% 4 21% 41% 13% 1	368
	21st to end	Night	21% 6% 20% 38% 13% 1	435
August	1st to 10th	Night	19% 5% 25% 39% 11% 1	568
	11th to 20th	Night	20% 7% 24% 35% 13% 1	562
	21st to end	Night	17% 7% 25% 35% 15% 1	632
September	1st to 10th	Night	17% 6% 32% 30% 14% 1	760
	11th to 20th	Night	20% 9% 24% 27% 16% 4	760
	21st to end	Night	20% 11% 26% 27% 14% 2	760
October	1st to 10th	Night	23% 9% 23% 28% 15% 1	760
	11th to 20th	Night	21% 14% 28% 25% 10% 2	760
	21st to end	Night	30% 17% 27% 21% 5%	836
November	1st to 10th	Night	25% 14% 30% 24% 7% 1	780
	11th to 20th	Night	26% 17% 30% 19% 7% 1	817
	21st to end	Night	29% 20% 26% 20% 5%	900
December	1st to 10th	Night	29% 16% 33% 17% 5%	900
	11th to 20th	Night	29% 23% 28% 16% 3	900
	21st to end	Night	29% 21% 28% 19% 3	975

Page generated at 2025-04-08 09:17:30. Version ac07

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