Jonesport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jonesport clear sky chart from 2005-11-06 to 2025-12-03.

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	20% 10% 3 7% 4 4 4 3 5% 6% 34%	126681
	Night	20% 10% 3 7% 4 4 4 3 5% 6% 34%	124081
Transparency	Day	32% 38% 7% 13% 8% 1	130214
	Night	32% 38% 7% 14% 9% 1	128636
Seeing	Day	24% 7% 25% 28% 14% 2	17510
	Night	25% 9% 26% 26% 12% 2	25635

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	18% 10% 3 7% 4 4 5% 4 5% 7% 34%	3440
	11th to 20th	Day	15% 10% 3 8% 4 4 4 4 4 5% 40%	3570
	21st to end	Day	14% 10% 3 8% 5% 4 3 3 6% 6% 36%	4259
February	1st to 10th	Day	19% 12% 3 6% 6% 4 4 5% 5% 8% 28%	1800
	11th to 20th	Day	15% 11% 3 6% 5% 4 5% 4 6% 8% 33%	1798
	21st to end	Day	14% 10% 2 7% 5% 5% 5% 5% 5% 5% 36%	1650
March	1st to 10th	Day	26% 9% 3 6% 4 4 4 3 5% 6% 30%	4631
	11th to 20th	Day	22% 10% 2 6% 3 3 4 3 6% 6% 34%	4980
	21st to end	Day	29% 9% 2 6% 4 4 4 3 5% 5% 29%	5466
April	1st to 10th	Day	21% 10% 3 6% 4 3 4 4 5% 6% 34%	2329
	11th to 20th	Day	22% 8% 2 5% 3 3 3 3 5% 7% 39%	2572
	21st to end	Day	21% 7% 2 6% 5% 3 4 3 5% 6% 38%	2600
May	1st to 10th	Day	29% 11% 4 8% 5% 4 3 3 4 6% 25%	5886
	11th to 20th	Day	21% 9% 3 7% 4 4 5% 4 5% 6% 33%	5861
	21st to end	Day	20% 11% 4 8% 4 4 4 4 5% 6% 30%	7122
June	1st to 10th	Day	23% 9% 3 7% 5% 4 3 4 5% 7% 31%	3000
	11th to 20th	Day	20% 9% 2 6% 5% 4 4 4 4 6% 36%	3000
	21st to end	Day	28% 10% 3 6% 4 4 3 4 4 7% 27%	3000
July	1st to 10th	Day	21% 12% 4 9% 5% 4 4 3 5% 7% 25%	6820
	11th to 20th	Day	18% 14% 3 10% 5% 4 4 3 5% 7% 27%	6366
	21st to end	Day	16% 8% 2 8% 5% 5% 4 4 6% 7% 35%	6614
August	1st to 10th	Day	22% 10% 3 8% 4 5% 4 3 4 6% 30%	4235
	11th to 20th	Day	17% 11% 4 8% 5% 4 4 3 5% 7% 32%	4175
	21st to end	Day	11% 6% 3 6% 4 4 4 3 4 6% 47%	4675
September	1st to 10th	Day	14% 6% 2 5% 3 3 4 4 5% 8% 47%	2320
	11th to 20th	Day	15% 7% 2 4 3 3 3 3 4 6% 49%	2200
	21st to end	Day	17% 8% 3 5% 3 3 3 3 4 6% 43%	2200
October	1st to 10th	Day	15% 8% 2 5% 3 3 4 4 5% 7% 43%	2092
	11th to 20th	Day	18% 6% 2 5% 4 4 4 4 5% 7% 42%	2000
	21st to end	Day	21% 8% 3 6% 3 4 3 3 6% 7% 39%	2040
November	1st to 10th	Day	18% 8% 2 6% 4 4 4 3 5% 6% 40%	1851
	11th to 20th	Day	21% 6% 2 5% 3 3 3 3 5% 7% 43%	1752
	21st to end	Day	21% 10% 2 5% 4 3 3 3 5% 6% 37%	1680
December	1st to 10th	Day	22% 8% 2 4 3 2 3 3 5% 6% 41%	2603
	11th to 20th	Day	23% 8% 3 6% 4 4 4 3 4 5% 36%	2618
	21st to end	Day	22% 13% 3 5% 3 3 3 3 4 6% 37%	3476
January	1st to 10th	Night	14% 12% 3 7% 5% 3 3 3 5% 6% 38%	6509
	11th to 20th	Night	15% 11% 4 9% 5% 5% 5% 4 5% 5% 31%	6315
	21st to end	Night	13% 9% 3 8% 4 4 5% 4 6% 6% 38%	6695
February	1st to 10th	Night	19% 11% 3 7% 5% 4 4 5% 6% 8% 28%	2600
	11th to 20th	Night	16% 10% 3 7% 5% 4 5% 3 5% 6% 36%	2488
	21st to end	Night	15% 10% 4 7% 5% 4 4 4 4 7% 36%	1980
March	1st to 10th	Night	26% 10% 3 8% 4 4 4 3 4 5% 30%	5195
	11th to 20th	Night	17% 12% 3 7% 4 4 4 4 6% 7% 30%	4979
	21st to end	Night	29% 8% 2 6% 4 3 4 4 5% 5% 30%	5466
April	1st to 10th	Night	24% 11% 3 6% 4 3 4 3 5% 6% 32%	2067
	11th to 20th	Night	22% 10% 3 6% 4 3 4 3 4 6% 35%	1778
	21st to end	Night	25% 9% 3 7% 4 3 4 3 5% 5% 32%	1800
May	1st to 10th	Night	29% 11% 4 8% 3 3 3 3 3 5% 28%	4054
	11th to 20th	Night	24% 8% 3 7% 4 3 4 4 6% 6% 31%	4033
	21st to end	Night	18% 13% 3 8% 5% 4 4 3 5% 6% 30%	3798
June	1st to 10th	Night	27% 10% 2 6% 4 4 4 3 6% 9% 25%	1400
	11th to 20th	Night	23% 10% 1 7% 4 3 4 3 4 7% 34%	1400
	21st to end	Night	30% 9% 3 6% 4 4 3 3 4 6% 28%	1400
July	1st to 10th	Night	21% 13% 4 9% 6% 5% 5% 4 6% 6% 21%	3160
	11th to 20th	Night	22% 15% 3 8% 4 4 3 3 5% 6% 26%	3590
	21st to end	Night	15% 10% 3 8% 5% 3 4 3 6% 7% 36%	4190
August	1st to 10th	Night	24% 13% 4 8% 4 3 4 3 5% 6% 26%	2915
	11th to 20th	Night	20% 10% 3 7% 5% 4 5% 4 5% 8% 29%	2872
	21st to end	Night	12% 7% 4 8% 3 3 4 3 5% 6% 45%	3223
September	1st to 10th	Night	16% 7% 2 5% 3 3 4 3 4 7% 46%	2076
	11th to 20th	Night	16% 8% 3 5% 3 2 2 3 5% 6% 47%	2200
	21st to end	Night	18% 7% 2 6% 3 2 4 3 5% 6% 45%	2200
October	1st to 10th	Night	18% 6% 2 5% 4 4 4 3 5% 7% 43%	2306
	11th to 20th	Night	19% 5% 2 5% 4 4 3 3 5% 7% 43%	2400
	21st to end	Night	22% 9% 3 5% 4 3 4 3 4 6% 38%	2798
November	1st to 10th	Night	19% 7% 2 5% 4 3 4 3 5% 6% 41%	2667
	11th to 20th	Night	18% 8% 2 6% 4 4 4 4 5% 6% 39%	2867
	21st to end	Night	20% 8% 3 5% 4 4 4 4 6% 7% 36%	2940
December	1st to 10th	Night	20% 9% 3 6% 3 3 4 3 6% 7% 36%	4627
	11th to 20th	Night	24% 8% 2 5% 3 3 3 3 4 5% 40%	5591
	21st to end	Night	22% 11% 3 6% 4 3 3 3 5% 5% 35%	7502

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	37% 28% 9% 21% 6%	3441
	11th to 20th	Day	32% 27% 9% 20% 10% 2	3600
	21st to end	Day	35% 29% 7% 11% 13% 5%	4259
February	1st to 10th	Day	20% 61% 4 6% 6% 2	1800
	11th to 20th	Day	20% 60% 4 9% 7% 1	1806
	21st to end	Day	17% 61% 4 8% 7% 3	1650
March	1st to 10th	Day	42% 29% 5% 7% 11% 5%	4635
	11th to 20th	Day	37% 31% 12% 12% 6% 1	4980
	21st to end	Day	45% 29% 4 10% 11% 1	5466
April	1st to 10th	Day	21% 61% 3 7% 6% 2	2329
	11th to 20th	Day	17% 62% 4 11% 4 1	2572
	21st to end	Day	19% 61% 3 9% 7% 1	2600
May	1st to 10th	Day	46% 30% 8% 12% 3	5897
	11th to 20th	Day	39% 31% 8% 17% 3 2	5865
	21st to end	Day	40% 30% 8% 11% 9% 1	7122
June	1st to 10th	Day	18% 62% 3 11% 6%	3000
	11th to 20th	Day	17% 62% 5% 10% 6% 1	3000
	21st to end	Day	19% 59% 4 10% 7% 1	3000
July	1st to 10th	Day	47% 26% 8% 13% 7%	6745
	11th to 20th	Day	42% 29% 8% 14% 6% 1	6290
	21st to end	Day	34% 28% 10% 18% 10% 1	6425
August	1st to 10th	Day	37% 37% 6% 15% 5%	4222
	11th to 20th	Day	35% 37% 12% 11% 5%	4214
	21st to end	Day	22% 37% 7% 18% 16% 1	4675
September	1st to 10th	Day	15% 57% 5% 13% 9% 1	2320
	11th to 20th	Day	19% 56% 4 12% 9% 1	2200
	21st to end	Day	15% 57% 4 14% 9% 1	2200
October	1st to 10th	Day	29% 37% 9% 17% 7% 1	3404
	11th to 20th	Day	15% 36% 5% 27% 17%	3240
	21st to end	Day	20% 36% 13% 17% 12% 3	3277
November	1st to 10th	Day	23% 53% 6% 12% 5% 1	1851
	11th to 20th	Day	20% 54% 5% 11% 8% 2	1752
	21st to end	Day	22% 54% 6% 11% 6%	1680
December	1st to 10th	Day	26% 36% 10% 17% 11%	2603
	11th to 20th	Day	35% 32% 7% 10% 12% 5%	2618
	21st to end	Day	37% 28% 8% 14% 11% 3	3476
January	1st to 10th	Night	34% 27% 8% 22% 8% 1	6509
	11th to 20th	Night	39% 28% 8% 16% 8% 1	6360
	21st to end	Night	33% 29% 6% 15% 13% 4	6695
February	1st to 10th	Night	21% 61% 4 6% 7% 1	2600
	11th to 20th	Night	19% 60% 2 9% 9% 1	2491
	21st to end	Night	18% 61% 2 7% 8% 3	1980
March	1st to 10th	Night	43% 29% 4 8% 10% 6%	5204
	11th to 20th	Night	36% 32% 15% 10% 6%	4980
	21st to end	Night	45% 29% 3 11% 12% 1	5466
April	1st to 10th	Night	21% 61% 2 6% 8% 3	2067
	11th to 20th	Night	21% 62% 3 9% 4 1	1778
	21st to end	Night	21% 61% 4 6% 6% 1	1800
May	1st to 10th	Night	46% 29% 9% 11% 5%	4060
	11th to 20th	Night	38% 31% 11% 14% 5% 1	4034
	21st to end	Night	39% 31% 10% 15% 6%	3799
June	1st to 10th	Night	20% 62% 2 11% 4 1	1400
	11th to 20th	Night	19% 61% 4 11% 5% 1	1400
	21st to end	Night	20% 60% 2 11% 7% 1	1400
July	1st to 10th	Night	48% 28% 7% 13% 5%	3125
	11th to 20th	Night	46% 28% 7% 12% 7%	3543
	21st to end	Night	34% 27% 11% 17% 9% 1	4065
August	1st to 10th	Night	41% 36% 5% 12% 5%	2903
	11th to 20th	Night	34% 38% 9% 14% 4	2899
	21st to end	Night	24% 38% 5% 19% 14% 1	3223
September	1st to 10th	Night	15% 56% 4 16% 8% 1	2076
	11th to 20th	Night	19% 56% 4 11% 8% 1	2200
	21st to end	Night	16% 57% 4 14% 9% 1	2200
October	1st to 10th	Night	25% 36% 10% 17% 11% 1	3774
	11th to 20th	Night	18% 35% 7% 21% 19%	3899
	21st to end	Night	24% 36% 5% 22% 11% 2	4511
November	1st to 10th	Night	21% 53% 6% 11% 8% 1	2667
	11th to 20th	Night	20% 54% 3 12% 9% 1	2867
	21st to end	Night	22% 54% 6% 8% 8% 1	2940
December	1st to 10th	Night	29% 36% 5% 21% 9%	4627
	11th to 20th	Night	31% 32% 8% 13% 13% 2	5592
	21st to end	Night	37% 28% 8% 13% 12% 2	7502

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% 17% 38% 14% 9% 1	200
	11th to 20th	Day	26% 14% 32% 22% 6% 2	200
	21st to end	Day	21% 12% 38% 21% 7% 1	350
February	1st to 10th	Day	26% 14% 35% 20% 6%	400
	11th to 20th	Day	22% 16% 42% 17% 3	419
	21st to end	Day	19% 15% 34% 26% 7%	414
March	1st to 10th	Day	25% 13% 33% 24% 5%	500
	11th to 20th	Day	21% 15% 31% 23% 9% 1	500
	21st to end	Day	26% 11% 31% 23% 7% 2	550
April	1st to 10th	Day	28% 10% 34% 22% 5% 2	500
	11th to 20th	Day	26% 8% 32% 26% 7% 2	492
	21st to end	Day	23% 6% 32% 28% 9% 1	500
May	1st to 10th	Day	27% 8% 28% 27% 9% 1	503
	11th to 20th	Day	21% 5% 24% 34% 14% 2	527
	21st to end	Day	29% 3 24% 29% 14% 2	770
June	1st to 10th	Day	25% 4 22% 31% 16% 2	730
	11th to 20th	Day	25% 3 18% 32% 18% 5%	730
	21st to end	Day	33% 3 13% 32% 16% 2	730
July	1st to 10th	Day	26% 4 13% 34% 20% 2	720
	11th to 20th	Day	26% 3 10% 35% 22% 4	529
	21st to end	Day	22% 3 14% 34% 24% 3	576
August	1st to 10th	Day	17% 2 16% 33% 27% 6%	526
	11th to 20th	Day	21% 3 13% 31% 24% 7%	519
	21st to end	Day	20% 2 14% 34% 24% 5%	583
September	1st to 10th	Day	16% 3 17% 35% 25% 4	530
	11th to 20th	Day	20% 4 21% 27% 22% 7%	530
	21st to end	Day	19% 3 22% 31% 20% 5%	530
October	1st to 10th	Day	18% 6% 22% 30% 21% 3	469
	11th to 20th	Day	18% 7% 27% 27% 18% 2	420
	21st to end	Day	25% 7% 29% 27% 10% 1	462
November	1st to 10th	Day	20% 12% 32% 25% 9% 2	425
	11th to 20th	Day	23% 11% 34% 24% 7% 1	430
	21st to end	Day	27% 14% 32% 20% 6%	430
December	1st to 10th	Day	26% 10% 37% 21% 5% 1	396
	11th to 20th	Day	29% 17% 32% 17% 5% 1	200
	21st to end	Day	30% 15% 27% 20% 7% 1	220
January	1st to 10th	Night	25% 17% 34% 19% 5%	835
	11th to 20th	Night	27% 16% 32% 20% 5%	800
	21st to end	Night	20% 18% 39% 20% 4	880
February	1st to 10th	Night	25% 17% 36% 18% 4	800
	11th to 20th	Night	21% 22% 35% 19% 3 1	783
	21st to end	Night	21% 14% 37% 22% 5%	660
March	1st to 10th	Night	23% 14% 38% 23% 2	800
	11th to 20th	Night	23% 11% 31% 26% 8% 1	800
	21st to end	Night	25% 9% 33% 24% 8% 1	880
April	1st to 10th	Night	30% 9% 33% 22% 6%	770
	11th to 20th	Night	28% 5% 29% 29% 9%	594
	21st to end	Night	30% 4 26% 26% 12% 3	600
May	1st to 10th	Night	29% 2 24% 31% 11% 3	600
	11th to 20th	Night	30% 3 18% 35% 14% 1	592
	21st to end	Night	27% 2 20% 33% 15% 3	577
June	1st to 10th	Night	31% 2 16% 32% 18% 2	400
	11th to 20th	Night	27% 2 12% 36% 20% 3	400
	21st to end	Night	34% 2 10% 36% 17% 2	400
July	1st to 10th	Night	28% 4 10% 35% 23% 1	390
	11th to 20th	Night	30% 3 8% 31% 25% 3	388
	21st to end	Night	28% 2 7% 33% 28% 2	548
August	1st to 10th	Night	22% 3 8% 37% 26% 3	598
	11th to 20th	Night	25% 3 8% 32% 27% 4	592
	21st to end	Night	19% 2 9% 37% 28% 6%	660
September	1st to 10th	Night	17% 3 14% 37% 25% 3	725
	11th to 20th	Night	22% 2 18% 28% 25% 6%	800
	21st to end	Night	22% 3 20% 32% 18% 5%	800
October	1st to 10th	Night	22% 4 23% 28% 20% 3	800
	11th to 20th	Night	21% 7% 28% 26% 14% 3	800
	21st to end	Night	28% 10% 29% 26% 8%	880
November	1st to 10th	Night	24% 9% 30% 25% 10% 1	820
	11th to 20th	Night	22% 15% 32% 22% 9% 1	912
	21st to end	Night	24% 16% 32% 19% 7% 1	950
December	1st to 10th	Night	32% 10% 34% 18% 5%	911
	11th to 20th	Night	26% 21% 33% 16% 4	900
	21st to end	Night	28% 16% 33% 18% 5%	990

Page generated at 2025-11-30 01:00:55. Version ac07

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