Damariscotta River Association
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Damariscotta River Association clear sky chart from 2005-11-06 to 2026-04-02.

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% 8% 3 6% 4 4 4 3 5% 7% 38%	130330
	Night	18% 9% 3 6% 4 4 4 3 5% 6% 37%	131466
Transparency	Day	44% 6% 12% 21% 13% 2	133852
	Night	46% 6% 11% 21% 14% 2	136033
Seeing	Day	22% 15% 32% 21% 7% 2	17115
	Night	22% 13% 30% 25% 9% 1	25895

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	13% 7% 3 8% 5% 5% 5% 4 5% 7% 38%	4661
	11th to 20th	Day	16% 11% 3 6% 3 3 3 3 4 6% 42%	4650
	21st to end	Day	10% 10% 3 6% 4 4 4 3 4 5% 48%	5142
February	1st to 10th	Day	16% 11% 2 6% 4 4 5% 3 4 7% 37%	1890
	11th to 20th	Day	13% 8% 3 6% 6% 3 4 5% 5% 6% 39%	2011
	21st to end	Day	15% 11% 3 6% 5% 4 5% 4 5% 5% 38%	1730
March	1st to 10th	Day	23% 11% 2 7% 4 4 4 3 4 5% 32%	4576
	11th to 20th	Day	20% 11% 3 7% 4 4 3 2 5% 5% 36%	5059
	21st to end	Day	29% 7% 2 5% 4 3 4 3 5% 6% 31%	5633
April	1st to 10th	Day	21% 10% 3 7% 4 4 4 3 4 6% 34%	2412
	11th to 20th	Day	21% 6% 2 5% 4 4 3 4 5% 6% 39%	2506
	21st to end	Day	22% 7% 3 6% 4 5% 3 3 5% 5% 36%	2600
May	1st to 10th	Day	32% 11% 3 7% 4 4 4 3 4 5% 23%	5886
	11th to 20th	Day	18% 9% 3 9% 5% 4 4 4 5% 7% 31%	5861
	21st to end	Day	21% 7% 2 6% 4 4 4 4 7% 8% 34%	6943
June	1st to 10th	Day	22% 8% 2 6% 4 4 4 4 5% 8% 33%	2905
	11th to 20th	Day	18% 7% 2 5% 5% 4 4 3 5% 8% 38%	3000
	21st to end	Day	22% 8% 2 6% 4 4 4 5% 6% 7% 32%	2883
July	1st to 10th	Day	19% 8% 2 7% 4 4 5% 4 6% 9% 31%	6360
	11th to 20th	Day	16% 10% 2 6% 3 4 4 4 6% 9% 37%	6360
	21st to end	Day	16% 5% 2 5% 3 4 4 4 6% 8% 43%	6881
August	1st to 10th	Day	16% 8% 3 6% 4 4 5% 4 6% 8% 36%	4235
	11th to 20th	Day	17% 8% 3 7% 4 5% 5% 4 6% 7% 36%	4175
	21st to end	Day	8% 5% 2 6% 4 4 5% 4 6% 9% 47%	4553
September	1st to 10th	Day	12% 5% 2 4 4 4 4 3 6% 7% 49%	2327
	11th to 20th	Day	12% 6% 2 4 3 3 2 3 4 6% 55%	2200
	21st to end	Day	18% 7% 2 5% 3 4 4 3 4 7% 45%	2200
October	1st to 10th	Day	18% 7% 2 6% 4 4 4 4 4 6% 42%	2182
	11th to 20th	Day	18% 7% 2 6% 4 4 4 3 4 6% 43%	1951
	21st to end	Day	22% 7% 2 5% 4 4 4 3 4 5% 40%	1980
November	1st to 10th	Day	16% 6% 2 6% 4 4 3 3 5% 5% 45%	1851
	11th to 20th	Day	19% 5% 2 5% 4 3 3 3 5% 6% 46%	1890
	21st to end	Day	21% 8% 2 6% 3 2 2 3 4 6% 42%	1774
December	1st to 10th	Day	16% 10% 2 5% 3 3 3 3 4 6% 44%	2462
	11th to 20th	Day	19% 8% 2 4 3 3 3 3 3 5% 48%	2688
	21st to end	Day	21% 11% 3 6% 5% 4 4 3 4 5% 35%	3913
January	1st to 10th	Night	12% 9% 3 8% 4 4 4 3 5% 7% 41%	8234
	11th to 20th	Night	15% 12% 4 9% 5% 5% 4 4 5% 6% 32%	8235
	21st to end	Night	12% 10% 3 7% 4 4 4 3 5% 5% 43%	9025
February	1st to 10th	Night	16% 9% 4 6% 5% 4 5% 3 6% 6% 36%	2730
	11th to 20th	Night	13% 9% 3 6% 5% 4 4 4 5% 6% 40%	2489
	21st to end	Night	14% 10% 3 7% 5% 3 3 3 4 6% 41%	2076
March	1st to 10th	Night	27% 10% 2 7% 4 3 3 3 4 5% 31%	5484
	11th to 20th	Night	16% 10% 3 8% 5% 4 4 4 6% 6% 33%	5119
	21st to end	Night	25% 9% 2 6% 4 3 4 3 6% 6% 31%	5527
April	1st to 10th	Night	23% 11% 2 5% 4 4 5% 3 4 6% 34%	2011
	11th to 20th	Night	20% 7% 3 5% 5% 4 4 4 6% 7% 36%	1842
	21st to end	Night	22% 10% 3 5% 5% 3 4 3 5% 5% 35%	1800
May	1st to 10th	Night	31% 9% 3 7% 4 4 4 3 5% 6% 23%	4054
	11th to 20th	Night	21% 10% 3 7% 5% 5% 5% 4 6% 7% 28%	4033
	21st to end	Night	18% 10% 3 7% 5% 4 5% 4 6% 7% 31%	3973
June	1st to 10th	Night	23% 8% 2 7% 4 5% 5% 4 5% 8% 31%	1485
	11th to 20th	Night	17% 7% 3 6% 4 4 4 4 5% 8% 38%	1400
	21st to end	Night	23% 9% 2 6% 4 4 4 4 5% 8% 31%	1508
July	1st to 10th	Night	16% 9% 3 7% 5% 4 5% 4 6% 9% 32%	3600
	11th to 20th	Night	16% 12% 3 6% 4 5% 5% 4 6% 8% 33%	3600
	21st to end	Night	11% 7% 2 5% 4 4 5% 4 6% 10% 42%	3926
August	1st to 10th	Night	22% 8% 3 7% 5% 4 5% 4 5% 7% 31%	2913
	11th to 20th	Night	16% 10% 3 7% 5% 4 5% 4 6% 7% 32%	2872
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 6% 8% 47%	3343
September	1st to 10th	Night	12% 6% 2 6% 3 4 4 4 4 7% 48%	2072
	11th to 20th	Night	15% 7% 2 4 2 3 2 3 4 6% 53%	2200
	21st to end	Night	17% 5% 2 4 4 4 3 3 5% 7% 46%	2200
October	1st to 10th	Night	17% 8% 2 5% 4 3 4 3 5% 6% 42%	2216
	11th to 20th	Night	17% 6% 2 5% 4 4 4 4 5% 7% 43%	2445
	21st to end	Night	24% 7% 2 4 4 3 4 3 5% 6% 38%	2860
November	1st to 10th	Night	18% 6% 2 5% 4 3 3 3 4 6% 45%	2667
	11th to 20th	Night	17% 6% 2 5% 3 4 4 4 5% 6% 44%	2730
	21st to end	Night	17% 8% 2 6% 5% 3 4 4 5% 6% 41%	2840
December	1st to 10th	Night	17% 10% 2 5% 3 3 4 3 5% 7% 40%	4944
	11th to 20th	Night	23% 7% 2 4 4 3 3 3 4 5% 43%	5741
	21st to end	Night	22% 11% 3 6% 4 3 3 3 4 5% 37%	7272

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	44% 5% 13% 23% 14% 1	4662
	11th to 20th	Day	44% 4 10% 25% 14% 3	4680
	21st to end	Day	39% 4 10% 22% 20% 5%	5142
February	1st to 10th	Day	46% 6% 11% 21% 13% 3	1890
	11th to 20th	Day	43% 7% 12% 20% 14% 3	2020
	21st to end	Day	46% 5% 11% 20% 14% 4	1730
March	1st to 10th	Day	53% 5% 10% 11% 14% 7%	4579
	11th to 20th	Day	48% 5% 14% 20% 11% 2	5059
	21st to end	Day	52% 5% 6% 17% 16% 5%	5633
April	1st to 10th	Day	50% 5% 9% 17% 15% 4	2412
	11th to 20th	Day	44% 6% 11% 22% 14% 3	2506
	21st to end	Day	49% 5% 8% 19% 15% 4	2600
May	1st to 10th	Day	60% 9% 10% 14% 6% 1	5897
	11th to 20th	Day	50% 9% 13% 18% 8% 2	5865
	21st to end	Day	45% 9% 14% 20% 11% 1	6943
June	1st to 10th	Day	48% 7% 15% 21% 9%	2905
	11th to 20th	Day	43% 7% 13% 20% 15% 2	3000
	21st to end	Day	48% 9% 11% 20% 10% 1	2883
July	1st to 10th	Day	48% 8% 15% 20% 10%	6290
	11th to 20th	Day	42% 7% 16% 23% 11% 1	6285
	21st to end	Day	37% 7% 15% 27% 14% 1	6684
August	1st to 10th	Day	44% 7% 17% 24% 8%	4222
	11th to 20th	Day	44% 9% 18% 22% 8%	4214
	21st to end	Day	30% 9% 16% 26% 19% 1	4553
September	1st to 10th	Day	33% 7% 14% 28% 18% 1	2327
	11th to 20th	Day	31% 5% 12% 28% 21% 2	2200
	21st to end	Day	40% 6% 9% 27% 17% 1	2200
October	1st to 10th	Day	44% 7% 11% 23% 13% 2	3559
	11th to 20th	Day	32% 4 11% 30% 21% 1	3154
	21st to end	Day	35% 4 13% 26% 19% 3	3180
November	1st to 10th	Day	40% 5% 13% 24% 17% 2	1851
	11th to 20th	Day	39% 5% 10% 24% 18% 3	1890
	21st to end	Day	44% 4 17% 23% 11% 1	1774
December	1st to 10th	Day	41% 4 14% 27% 12% 1	2462
	11th to 20th	Day	40% 4 12% 19% 17% 8%	2688
	21st to end	Day	52% 6% 8% 17% 13% 4	3913
January	1st to 10th	Night	42% 5% 11% 27% 13% 1	8234
	11th to 20th	Night	52% 5% 11% 18% 12% 2	8280
	21st to end	Night	43% 4 7% 22% 18% 6%	9025
February	1st to 10th	Night	48% 5% 11% 20% 14% 3	2730
	11th to 20th	Night	45% 5% 10% 21% 17% 3	2491
	21st to end	Night	44% 4 10% 23% 14% 4	2076
March	1st to 10th	Night	56% 3 7% 14% 14% 7%	5494
	11th to 20th	Night	47% 7% 18% 19% 8% 2	5120
	21st to end	Night	52% 4 6% 15% 18% 4	5527
April	1st to 10th	Night	51% 4 8% 18% 15% 4	2011
	11th to 20th	Night	46% 5% 10% 21% 16% 2	1842
	21st to end	Night	50% 5% 11% 17% 14% 3	1800
May	1st to 10th	Night	60% 8% 12% 12% 7% 1	4060
	11th to 20th	Night	53% 9% 11% 18% 8% 1	4034
	21st to end	Night	49% 9% 12% 20% 9% 1	3974
June	1st to 10th	Night	52% 6% 11% 21% 9% 1	1485
	11th to 20th	Night	44% 7% 14% 20% 13% 2	1400
	21st to end	Night	51% 7% 12% 19% 10% 1	1508
July	1st to 10th	Night	48% 7% 13% 21% 11%	3560
	11th to 20th	Night	48% 7% 13% 21% 11%	3552
	21st to end	Night	35% 8% 17% 28% 11% 1	3809
August	1st to 10th	Night	53% 7% 13% 19% 7% 1	2902
	11th to 20th	Night	47% 9% 14% 20% 9%	2899
	21st to end	Night	32% 8% 14% 26% 18% 1	3343
September	1st to 10th	Night	34% 7% 12% 28% 17% 1	2072
	11th to 20th	Night	34% 5% 11% 27% 21% 2	2200
	21st to end	Night	38% 6% 11% 28% 16% 2	2200
October	1st to 10th	Night	40% 6% 14% 23% 16% 1	3619
	11th to 20th	Night	32% 4 11% 29% 24% 1	3981
	21st to end	Night	37% 5% 10% 28% 18% 3	4610
November	1st to 10th	Night	40% 6% 10% 26% 16% 2	2667
	11th to 20th	Night	41% 5% 11% 23% 18% 3	2730
	21st to end	Night	43% 6% 15% 20% 14% 2	2840
December	1st to 10th	Night	44% 4 9% 30% 12%	4944
	11th to 20th	Night	45% 4 11% 19% 18% 4	5742
	21st to end	Night	50% 5% 10% 17% 17% 1	7272

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	26% 23% 33% 15% 4	220
	11th to 20th	Day	29% 20% 31% 17% 2 1	220
	21st to end	Day	19% 26% 33% 18% 4	247
February	1st to 10th	Day	24% 22% 32% 19% 2	430
	11th to 20th	Day	24% 24% 38% 13% 2	517
	21st to end	Day	24% 21% 35% 17% 4	446
March	1st to 10th	Day	25% 21% 37% 15% 2	540
	11th to 20th	Day	23% 25% 35% 13% 3 1	540
	21st to end	Day	29% 22% 30% 13% 4 2	594
April	1st to 10th	Day	29% 24% 28% 13% 4 1	504
	11th to 20th	Day	26% 18% 34% 15% 5% 1	492
	21st to end	Day	27% 15% 37% 17% 3 1	500
May	1st to 10th	Day	29% 19% 30% 18% 4 1	503
	11th to 20th	Day	20% 14% 41% 17% 7% 1	527
	21st to end	Day	22% 15% 36% 22% 5% 1	573
June	1st to 10th	Day	21% 10% 34% 24% 9% 2	635
	11th to 20th	Day	19% 12% 33% 23% 11% 2	730
	21st to end	Day	22% 11% 31% 24% 10% 2	613
July	1st to 10th	Day	21% 8% 31% 29% 10% 2	525
	11th to 20th	Day	19% 7% 31% 30% 12% 2	524
	21st to end	Day	15% 7% 33% 30% 13% 2	576
August	1st to 10th	Day	13% 5% 32% 32% 15% 2	526
	11th to 20th	Day	16% 5% 31% 30% 12% 6%	519
	21st to end	Day	12% 8% 33% 31% 13% 3	583
September	1st to 10th	Day	15% 7% 31% 30% 14% 2	530
	11th to 20th	Day	15% 10% 31% 26% 11% 7%	530
	21st to end	Day	19% 10% 32% 24% 11% 5%	530
October	1st to 10th	Day	21% 14% 24% 26% 12% 3	519
	11th to 20th	Day	21% 17% 28% 24% 9% 2	420
	21st to end	Day	28% 14% 29% 22% 7%	462
November	1st to 10th	Day	22% 17% 30% 23% 6% 2	425
	11th to 20th	Day	24% 19% 34% 18% 5% 1	430
	21st to end	Day	24% 24% 27% 18% 6% 1	430
December	1st to 10th	Day	25% 16% 37% 17% 4 1	293
	11th to 20th	Day	31% 21% 34% 10% 3	220
	21st to end	Day	29% 23% 31% 12% 5% 1	242
January	1st to 10th	Night	21% 21% 36% 19% 3	840
	11th to 20th	Night	27% 20% 33% 16% 4	840
	21st to end	Night	19% 23% 36% 19% 3	924
February	1st to 10th	Night	22% 20% 35% 19% 3	840
	11th to 20th	Night	19% 23% 37% 18% 2	823
	21st to end	Night	21% 16% 39% 20% 4	692
March	1st to 10th	Night	26% 18% 34% 20% 2	840
	11th to 20th	Night	23% 15% 34% 20% 7%	840
	21st to end	Night	24% 15% 34% 21% 5% 1	924
April	1st to 10th	Night	30% 15% 32% 18% 4	805
	11th to 20th	Night	23% 10% 35% 26% 5% 1	658
	21st to end	Night	29% 11% 28% 26% 6% 1	600
May	1st to 10th	Night	26% 6% 29% 29% 8% 1	600
	11th to 20th	Night	24% 7% 32% 28% 8%	592
	21st to end	Night	26% 4 26% 33% 9% 1	454
June	1st to 10th	Night	25% 6% 21% 34% 13% 1	400
	11th to 20th	Night	20% 6% 23% 37% 14% 1	400
	21st to end	Night	26% 6% 20% 38% 10%	400
July	1st to 10th	Night	21% 4 16% 44% 15%	390
	11th to 20th	Night	20% 4 19% 38% 18% 2	388
	21st to end	Night	17% 4 19% 40% 19% 1	438
August	1st to 10th	Night	17% 3 21% 42% 17% 1	596
	11th to 20th	Night	16% 5% 19% 40% 19% 1	592
	21st to end	Night	14% 4 22% 38% 20% 2	728
September	1st to 10th	Night	15% 4 26% 35% 19% 2	800
	11th to 20th	Night	18% 6% 25% 27% 22% 3	800
	21st to end	Night	19% 5% 27% 31% 17% 2	800
October	1st to 10th	Night	21% 10% 23% 29% 17% 1	800
	11th to 20th	Night	19% 12% 31% 26% 10% 2	800
	21st to end	Night	28% 13% 29% 24% 6%	880
November	1st to 10th	Night	22% 11% 34% 24% 7% 1	820
	11th to 20th	Night	22% 16% 35% 21% 6% 1	840
	21st to end	Night	21% 21% 33% 19% 5%	898
December	1st to 10th	Night	27% 14% 38% 15% 6%	950
	11th to 20th	Night	26% 20% 34% 17% 3	950
	21st to end	Night	28% 17% 34% 18% 3	953

Page generated at 2026-03-30 02:18:40. Version ac07

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