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 2024-12-09.

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% 2 6% 4 4 4 4 5% 7% 38%	101310
	Night	19% 8% 3 6% 4 4 4 3 5% 6% 37%	98458
Transparency	Day	44% 7% 13% 22% 13% 2	104850
	Night	45% 6% 12% 21% 13% 2	103009
Seeing	Day	21% 14% 33% 22% 8% 2	15483
	Night	22% 12% 30% 25% 9% 1	24147

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	17% 7% 2 6% 5% 4 4 4 3 6% 41%	2517
	11th to 20th	Day	18% 6% 3 5% 4 4 3 3 5% 5% 43%	2520
	21st to end	Day	17% 13% 3 7% 4 3 4 2 4 5% 38%	2776
February	1st to 10th	Day	17% 11% 2 6% 5% 4 5% 3 4 7% 36%	1710
	11th to 20th	Day	14% 9% 4 6% 6% 3 4 5% 5% 6% 38%	1814
	21st to end	Day	16% 11% 3 6% 5% 4 5% 4 5% 6% 36%	1570
March	1st to 10th	Day	26% 13% 2 6% 3 4 4 3 4 5% 30%	3116
	11th to 20th	Day	18% 8% 3 7% 5% 5% 4 3 5% 6% 38%	3464
	21st to end	Day	26% 8% 3 5% 4 4 4 3 5% 6% 32%	3847
April	1st to 10th	Day	20% 10% 3 6% 4 4 5% 3 4 6% 35%	2280
	11th to 20th	Day	20% 6% 2 5% 4 4 3 4 5% 7% 39%	2379
	21st to end	Day	22% 7% 3 6% 4 5% 3 3 5% 5% 35%	2470
May	1st to 10th	Day	23% 9% 3 7% 5% 5% 4 3 6% 7% 28%	4106
	11th to 20th	Day	19% 9% 3 8% 4 4 4 4 5% 7% 34%	4081
	21st to end	Day	17% 7% 3 6% 4 4 4 4 7% 8% 38%	4831
June	1st to 10th	Day	22% 8% 2 6% 4 4 4 4 5% 8% 33%	2760
	11th to 20th	Day	18% 7% 2 5% 5% 4 5% 3 5% 8% 38%	2850
	21st to end	Day	23% 8% 2 6% 4 4 5% 5% 6% 7% 31%	2739
July	1st to 10th	Day	16% 7% 2 6% 5% 5% 5% 4 6% 9% 35%	4440
	11th to 20th	Day	13% 7% 2 6% 4 4 4 4 7% 10% 39%	4440
	21st to end	Day	21% 7% 2 5% 4 4 4 4 6% 8% 36%	4783
August	1st to 10th	Day	17% 8% 3 7% 4 4 5% 4 6% 8% 35%	4105
	11th to 20th	Day	17% 8% 3 7% 4 5% 5% 4 6% 7% 36%	4045
	21st to end	Day	8% 5% 2 6% 4 4 5% 4 6% 9% 47%	4414
September	1st to 10th	Day	12% 5% 2 4 4 4 4 3 6% 7% 49%	2211
	11th to 20th	Day	12% 6% 2 4 3 3 2 3 4 6% 54%	2090
	21st to end	Day	18% 7% 2 6% 3 4 4 3 4 7% 44%	2090
October	1st to 10th	Day	18% 7% 2 7% 4 4 4 4 4 6% 40%	2073
	11th to 20th	Day	18% 7% 2 6% 4 4 4 3 4 6% 43%	1854
	21st to end	Day	22% 7% 2 5% 4 4 4 3 4 5% 40%	1881
November	1st to 10th	Day	16% 6% 2 6% 4 4 3 3 5% 5% 46%	1761
	11th to 20th	Day	20% 5% 2 5% 4 3 3 3 5% 6% 46%	1800
	21st to end	Day	21% 8% 2 5% 3 2 2 3 4 6% 43%	1690
December	1st to 10th	Day	21% 9% 2 7% 4 3 3 3 4 5% 38%	1456
	11th to 20th	Day	22% 10% 2 5% 3 2 4 3 4 5% 41%	1668
	21st to end	Day	25% 9% 3 7% 5% 4 4 3 5% 5% 31%	2679
January	1st to 10th	Night	15% 9% 3 6% 3 4 4 3 5% 6% 42%	4429
	11th to 20th	Night	14% 9% 4 9% 5% 5% 4 3 5% 6% 37%	4440
	21st to end	Night	18% 12% 4 8% 5% 4 3 3 5% 5% 35%	4880
February	1st to 10th	Night	17% 9% 4 6% 5% 4 5% 3 6% 6% 35%	2470
	11th to 20th	Night	14% 9% 3 6% 6% 4 4 4 5% 5% 39%	2247
	21st to end	Night	15% 10% 3 7% 5% 3 3 3 4 6% 40%	1884
March	1st to 10th	Night	30% 12% 2 5% 4 3 3 3 4 4 32%	3724
	11th to 20th	Night	13% 8% 3 9% 6% 5% 5% 5% 7% 6% 33%	3494
	21st to end	Night	26% 9% 3 7% 4 4 4 3 5% 5% 30%	3771
April	1st to 10th	Night	23% 10% 2 5% 4 4 5% 3 4 6% 35%	1900
	11th to 20th	Night	19% 7% 3 5% 5% 4 4 3 6% 7% 37%	1749
	21st to end	Night	22% 9% 2 5% 5% 3 4 3 5% 5% 35%	1710
May	1st to 10th	Night	23% 8% 3 6% 4 4 5% 4 6% 7% 29%	2834
	11th to 20th	Night	19% 8% 3 8% 6% 6% 5% 5% 7% 8% 26%	2813
	21st to end	Night	17% 9% 3 7% 4 4 4 4 6% 7% 35%	2771
June	1st to 10th	Night	23% 7% 2 7% 4 5% 5% 4 5% 7% 31%	1411
	11th to 20th	Night	17% 7% 3 6% 4 4 4 4 5% 9% 37%	1330
	21st to end	Night	25% 9% 2 6% 4 4 4 4 5% 7% 30%	1432
July	1st to 10th	Night	16% 9% 3 7% 5% 5% 6% 5% 7% 9% 30%	2520
	11th to 20th	Night	16% 7% 2 6% 5% 5% 5% 4 7% 8% 36%	2520
	21st to end	Night	15% 8% 3 6% 4 4 5% 4 6% 9% 37%	2739
August	1st to 10th	Night	22% 8% 3 7% 5% 4 5% 3 5% 7% 30%	2823
	11th to 20th	Night	16% 11% 3 8% 5% 4 5% 4 6% 7% 31%	2782
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 6% 8% 47%	3240
September	1st to 10th	Night	12% 6% 2 6% 3 4 4 4 4 7% 47%	1968
	11th to 20th	Night	15% 7% 2 4 2 3 2 2 4 6% 52%	2090
	21st to end	Night	17% 5% 2 4 4 4 3 3 5% 7% 46%	2090
October	1st to 10th	Night	18% 8% 2 5% 4 4 5% 4 5% 7% 39%	2105
	11th to 20th	Night	17% 6% 2 6% 4 4 4 4 5% 7% 43%	2323
	21st to end	Night	25% 7% 2 4 4 3 3 3 5% 5% 38%	2717
November	1st to 10th	Night	17% 6% 2 5% 4 3 3 3 5% 6% 45%	2537
	11th to 20th	Night	17% 6% 2 5% 3 4 4 4 5% 6% 44%	2600
	21st to end	Night	17% 8% 2 6% 4 3 4 4 4 6% 41%	2705
December	1st to 10th	Night	21% 10% 2 5% 4 4 4 3 5% 6% 36%	2903
	11th to 20th	Night	23% 6% 2 4 4 3 3 3 4 6% 41%	3531
	21st to end	Night	25% 9% 2 6% 4 3 3 3 4 5% 35%	4976

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	43% 6% 14% 25% 11% 1	2518
	11th to 20th	Day	42% 6% 13% 24% 12% 2	2520
	21st to end	Day	48% 6% 12% 21% 12% 1	2776
February	1st to 10th	Day	47% 6% 11% 20% 13% 2	1710
	11th to 20th	Day	44% 7% 12% 20% 14% 3	1823
	21st to end	Day	48% 5% 11% 20% 12% 4	1570
March	1st to 10th	Day	56% 5% 10% 13% 13% 3	3119
	11th to 20th	Day	44% 6% 12% 22% 14% 3	3464
	21st to end	Day	51% 5% 7% 14% 18% 5%	3847
April	1st to 10th	Day	50% 5% 9% 18% 15% 4	2280
	11th to 20th	Day	43% 6% 11% 23% 15% 3	2379
	21st to end	Day	50% 5% 9% 18% 15% 4	2470
May	1st to 10th	Day	51% 11% 13% 16% 8% 1	4120
	11th to 20th	Day	46% 9% 16% 18% 9% 1	4085
	21st to end	Day	41% 10% 15% 19% 13% 1	4831
June	1st to 10th	Day	48% 8% 15% 21% 9%	2760
	11th to 20th	Day	43% 7% 13% 20% 15% 2	2850
	21st to end	Day	49% 9% 11% 19% 9% 1	2739
July	1st to 10th	Day	44% 9% 14% 22% 11%	4370
	11th to 20th	Day	38% 8% 18% 25% 11% 1	4365
	21st to end	Day	44% 8% 14% 22% 12% 1	4631
August	1st to 10th	Day	45% 7% 17% 24% 7%	4092
	11th to 20th	Day	44% 9% 18% 21% 8%	4084
	21st to end	Day	30% 9% 16% 25% 19% 1	4414
September	1st to 10th	Day	33% 7% 14% 27% 18% 1	2211
	11th to 20th	Day	32% 6% 12% 28% 20% 2	2090
	21st to end	Day	41% 6% 9% 27% 16% 1	2090
October	1st to 10th	Day	45% 8% 11% 22% 13% 1	3450
	11th to 20th	Day	32% 4 11% 30% 22% 1	3057
	21st to end	Day	35% 4 13% 26% 20% 3	3081
November	1st to 10th	Day	39% 5% 13% 24% 16% 2	1761
	11th to 20th	Day	39% 5% 10% 24% 19% 4	1800
	21st to end	Day	43% 4 17% 23% 12% 1	1690
December	1st to 10th	Day	49% 5% 11% 21% 12% 1	1456
	11th to 20th	Day	46% 5% 9% 21% 14% 4	1668
	21st to end	Day	55% 7% 10% 17% 9% 3	2679
January	1st to 10th	Night	43% 5% 12% 28% 10% 2	4429
	11th to 20th	Night	47% 6% 14% 20% 11% 2	4440
	21st to end	Night	51% 5% 11% 21% 11% 1	4880
February	1st to 10th	Night	48% 6% 12% 18% 13% 3	2470
	11th to 20th	Night	46% 5% 9% 21% 16% 3	2249
	21st to end	Night	45% 5% 10% 22% 14% 5%	1884
March	1st to 10th	Night	57% 3 9% 16% 11% 4	3734
	11th to 20th	Night	45% 8% 13% 21% 10% 3	3495
	21st to end	Night	54% 4 6% 15% 15% 4	3771
April	1st to 10th	Night	51% 4 8% 18% 16% 4	1900
	11th to 20th	Night	45% 6% 10% 22% 16% 2	1749
	21st to end	Night	50% 5% 11% 17% 14% 4	1710
May	1st to 10th	Night	49% 11% 16% 15% 8% 1	2840
	11th to 20th	Night	51% 10% 14% 16% 7% 2	2814
	21st to end	Night	45% 10% 13% 18% 13% 1	2772
June	1st to 10th	Night	52% 7% 11% 20% 8% 1	1411
	11th to 20th	Night	44% 7% 15% 19% 13% 2	1330
	21st to end	Night	52% 7% 12% 19% 9% 1	1432
July	1st to 10th	Night	48% 8% 14% 18% 12%	2480
	11th to 20th	Night	43% 8% 14% 24% 11%	2472
	21st to end	Night	41% 9% 14% 24% 11% 1	2651
August	1st to 10th	Night	54% 7% 14% 18% 7% 1	2812
	11th to 20th	Night	48% 9% 14% 19% 9%	2809
	21st to end	Night	32% 8% 15% 26% 19% 1	3240
September	1st to 10th	Night	35% 8% 12% 28% 17% 1	1968
	11th to 20th	Night	35% 5% 12% 27% 20% 2	2090
	21st to end	Night	38% 6% 11% 28% 15% 2	2090
October	1st to 10th	Night	41% 6% 14% 23% 15% 1	3508
	11th to 20th	Night	31% 4 10% 28% 24% 1	3859
	21st to end	Night	37% 4 10% 28% 18% 3	4467
November	1st to 10th	Night	40% 6% 11% 27% 15% 2	2537
	11th to 20th	Night	40% 5% 11% 23% 18% 3	2600
	21st to end	Night	43% 6% 15% 20% 14% 1	2705
December	1st to 10th	Night	50% 5% 10% 22% 12% 1	2903
	11th to 20th	Night	45% 5% 11% 21% 17% 1	3532
	21st to end	Night	51% 6% 12% 18% 13% 1	4976

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% 22% 29% 18% 4	180
	11th to 20th	Day	29% 17% 34% 17% 2 1	180
	21st to end	Day	18% 22% 35% 21% 4	202
February	1st to 10th	Day	26% 21% 32% 19% 2	370
	11th to 20th	Day	23% 25% 37% 13% 1	440
	21st to end	Day	25% 19% 34% 18% 4	382
March	1st to 10th	Day	24% 18% 40% 15% 2	460
	11th to 20th	Day	20% 24% 37% 15% 3 1	460
	21st to end	Day	26% 23% 30% 14% 5% 2	506
April	1st to 10th	Day	28% 22% 30% 14% 4 1	460
	11th to 20th	Day	24% 17% 35% 16% 6% 1	452
	21st to end	Day	27% 15% 37% 17% 3 1	460
May	1st to 10th	Day	27% 20% 31% 18% 4 1	463
	11th to 20th	Day	19% 14% 42% 17% 7% 1	487
	21st to end	Day	21% 15% 36% 22% 5% 1	529
June	1st to 10th	Day	21% 10% 34% 24% 9% 2	590
	11th to 20th	Day	19% 11% 33% 24% 12% 2	680
	21st to end	Day	23% 11% 31% 25% 10% 2	569
July	1st to 10th	Day	20% 7% 32% 30% 10% 2	485
	11th to 20th	Day	17% 7% 31% 32% 12% 2	484
	21st to end	Day	15% 7% 33% 30% 13% 2	532
August	1st to 10th	Day	15% 6% 32% 31% 15% 2	486
	11th to 20th	Day	16% 5% 32% 30% 12% 5%	479
	21st to end	Day	13% 8% 32% 31% 13% 4	539
September	1st to 10th	Day	15% 8% 31% 30% 14% 2	490
	11th to 20th	Day	16% 10% 31% 26% 11% 7%	490
	21st to end	Day	20% 10% 31% 24% 10% 5%	490
October	1st to 10th	Day	22% 13% 25% 27% 11% 3	480
	11th to 20th	Day	21% 16% 27% 24% 9% 2	390
	21st to end	Day	29% 13% 30% 22% 7%	429
November	1st to 10th	Day	21% 17% 30% 24% 6% 2	395
	11th to 20th	Day	25% 19% 34% 19% 5% 1	400
	21st to end	Day	25% 24% 27% 18% 6% 1	400
December	1st to 10th	Day	24% 15% 38% 17% 5% 1	266
	11th to 20th	Day	31% 21% 36% 9% 3 1	180
	21st to end	Day	29% 24% 31% 11% 4 1	198
January	1st to 10th	Night	21% 21% 35% 20% 4	760
	11th to 20th	Night	26% 21% 33% 16% 4	760
	21st to end	Night	19% 22% 36% 19% 3	836
February	1st to 10th	Night	22% 19% 36% 19% 4	760
	11th to 20th	Night	19% 23% 37% 18% 2	743
	21st to end	Night	21% 16% 38% 20% 4	628
March	1st to 10th	Night	25% 17% 35% 20% 2	760
	11th to 20th	Night	22% 16% 35% 20% 7%	760
	21st to end	Night	24% 15% 34% 21% 5% 1	836
April	1st to 10th	Night	29% 15% 33% 19% 4 1	760
	11th to 20th	Night	22% 10% 35% 27% 5% 1	625
	21st to end	Night	28% 11% 28% 26% 6% 1	570
May	1st to 10th	Night	25% 6% 30% 30% 8% 1	570
	11th to 20th	Night	24% 6% 33% 29% 7%	562
	21st to end	Night	26% 4 26% 34% 10% 1	431
June	1st to 10th	Night	26% 5% 21% 34% 13% 1	380
	11th to 20th	Night	21% 5% 22% 37% 15% 1	380
	21st to end	Night	27% 6% 19% 38% 10%	380
July	1st to 10th	Night	22% 4 15% 43% 16%	370
	11th to 20th	Night	20% 4 19% 38% 18% 2	368
	21st to end	Night	18% 3 19% 40% 19% 1	416
August	1st to 10th	Night	17% 3 21% 42% 16% 1	566
	11th to 20th	Night	16% 4 20% 40% 18% 1	562
	21st to end	Night	15% 3 22% 38% 20% 2	691
September	1st to 10th	Night	15% 4 26% 35% 19% 2	760
	11th to 20th	Night	19% 6% 25% 25% 21% 3	760
	21st to end	Night	19% 5% 27% 30% 17% 2	760
October	1st to 10th	Night	21% 9% 23% 30% 16% 1	760
	11th to 20th	Night	19% 12% 31% 26% 10% 2	760
	21st to end	Night	29% 13% 28% 23% 6%	836
November	1st to 10th	Night	21% 11% 34% 25% 8% 1	780
	11th to 20th	Night	21% 16% 35% 21% 7% 1	800
	21st to end	Night	22% 20% 33% 19% 5%	853
December	1st to 10th	Night	26% 13% 40% 15% 6%	893
	11th to 20th	Night	25% 19% 35% 18% 3	850
	21st to end	Night	28% 17% 34% 18% 3	861

Page generated at 2024-12-06 03:54:48. Version ac07

Copyright © 2024 Attilla Danko.