Prinyer's Cove
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Prinyer's Cove clear sky chart from 2005-11-06 to 2024-08-30.

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	15% 9% 3 7% 5% 5% 4 4 6% 7% 35%	95904
	Night	17% 10% 3 8% 5% 4 4 4 5% 6% 33%	93141
Transparency	Day	24% 52% 7% 12% 6% 1	95623
	Night	27% 52% 6% 10% 6%	92976
Seeing	Day	19% 7% 23% 30% 17% 4	14272
	Night	21% 7% 27% 29% 14% 2	23448

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% 15% 6% 9% 5% 5% 4 3 5% 5% 27%	2517
	11th to 20th	Day	13% 18% 7% 15% 8% 6% 5% 3 5% 4 16%	2520
	21st to end	Day	17% 17% 6% 11% 7% 6% 4 4 4 4 18%	3069
February	1st to 10th	Day	15% 13% 5% 12% 7% 5% 5% 4 5% 6% 22%	1710
	11th to 20th	Day	14% 12% 6% 10% 6% 5% 6% 4 5% 5% 28%	1663
	21st to end	Day	20% 13% 4 8% 6% 5% 4 4 5% 5% 27%	1546
March	1st to 10th	Day	21% 10% 4 8% 6% 4 3 3 5% 4 32%	3239
	11th to 20th	Day	10% 12% 4 10% 6% 5% 5% 4 5% 6% 33%	3480
	21st to end	Day	14% 8% 3 6% 4 4 4 3 5% 6% 42%	3941
April	1st to 10th	Day	19% 10% 3 7% 5% 5% 4 4 4 6% 33%	2280
	11th to 20th	Day	19% 7% 3 7% 5% 4 3 4 4 7% 39%	2254
	21st to end	Day	20% 8% 3 7% 6% 4 4 4 6% 6% 32%	2389
May	1st to 10th	Day	18% 8% 3 8% 5% 4 4 4 6% 7% 33%	4358
	11th to 20th	Day	14% 9% 3 7% 5% 5% 4 4 6% 7% 36%	4398
	21st to end	Day	11% 5% 2 6% 4 5% 5% 4 6% 9% 43%	4837
June	1st to 10th	Day	16% 6% 2 7% 5% 4 5% 4 5% 9% 35%	2660
	11th to 20th	Day	13% 6% 2 5% 4 4 4 6% 7% 9% 41%	2660
	21st to end	Day	13% 7% 3 6% 5% 3 4 4 6% 8% 40%	2660
July	1st to 10th	Day	10% 5% 2 6% 4 4 4 4 7% 9% 44%	4440
	11th to 20th	Day	10% 4 2 5% 4 4 4 4 7% 10% 46%	4440
	21st to end	Day	8% 5% 2 6% 4 5% 5% 5% 7% 9% 43%	4814
August	1st to 10th	Day	10% 5% 2 6% 4 5% 5% 4 6% 8% 45%	2482
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 5% 7% 10% 42%	2428
	21st to end	Day	12% 4 2 5% 4 4 5% 4 6% 9% 45%	2486
September	1st to 10th	Day	11% 6% 2 5% 4 5% 4 4 5% 8% 46%	2160
	11th to 20th	Day	10% 6% 2 5% 4 3 4 4 5% 7% 51%	2160
	21st to end	Day	14% 6% 2 7% 4 5% 5% 3 6% 8% 40%	1900
October	1st to 10th	Day	18% 8% 3 6% 5% 4 4 3 5% 7% 37%	1800
	11th to 20th	Day	20% 7% 2 7% 5% 4 5% 4 7% 8% 32%	1800
	21st to end	Day	26% 10% 3 7% 4 5% 4 4 4 7% 26%	1911
November	1st to 10th	Day	15% 8% 3 6% 5% 5% 5% 4 6% 7% 35%	1664
	11th to 20th	Day	15% 10% 3 8% 6% 5% 6% 4 5% 7% 31%	1520
	21st to end	Day	20% 13% 3 8% 5% 5% 4 4 5% 7% 25%	1520
December	1st to 10th	Day	22% 15% 4 9% 5% 5% 5% 4 5% 6% 21%	1520
	11th to 20th	Day	18% 15% 5% 9% 6% 4 4 4 4 6% 25%	1906
	21st to end	Day	29% 13% 4 9% 5% 4 4 2 4 5% 20%	2772
January	1st to 10th	Night	18% 15% 4 10% 6% 5% 5% 4 5% 5% 23%	4429
	11th to 20th	Night	15% 13% 5% 17% 6% 6% 5% 4 5% 5% 18%	4440
	21st to end	Night	21% 16% 5% 11% 6% 5% 4 3 4 4 20%	4583
February	1st to 10th	Night	17% 13% 5% 12% 6% 5% 5% 4 4 5% 25%	2470
	11th to 20th	Night	15% 13% 4 9% 4 5% 4 4 5% 6% 29%	2403
	21st to end	Night	17% 10% 4 9% 4 5% 5% 4 6% 7% 29%	1907
March	1st to 10th	Night	19% 10% 4 8% 5% 5% 4 3 5% 6% 33%	3598
	11th to 20th	Night	20% 13% 4 8% 4 4 4 3 5% 6% 29%	3479
	21st to end	Night	17% 8% 3 6% 3 3 3 3 5% 7% 43%	3690
April	1st to 10th	Night	21% 9% 3 6% 4 4 5% 3 5% 7% 34%	1900
	11th to 20th	Night	18% 8% 4 7% 4 4 4 3 5% 6% 36%	1875
	21st to end	Night	18% 9% 3 6% 5% 4 4 4 6% 6% 35%	1807
May	1st to 10th	Night	23% 9% 3 7% 4 4 4 3 5% 5% 33%	2580
	11th to 20th	Night	18% 7% 2 6% 4 4 5% 4 6% 7% 36%	2495
	21st to end	Night	11% 6% 2 6% 4 4 5% 5% 6% 7% 43%	2738
June	1st to 10th	Night	14% 6% 3 6% 5% 5% 5% 4 8% 9% 35%	1520
	11th to 20th	Night	10% 5% 2 6% 5% 4 4 5% 7% 8% 44%	1520
	21st to end	Night	13% 8% 3 7% 5% 3 5% 3 6% 8% 39%	1520
July	1st to 10th	Night	10% 5% 2 8% 5% 5% 5% 4 7% 8% 40%	2520
	11th to 20th	Night	12% 6% 2 5% 4 3 4 3 6% 9% 45%	2520
	21st to end	Night	9% 5% 2 5% 4 4 4 4 7% 8% 47%	2739
August	1st to 10th	Night	8% 6% 3 6% 4 4 5% 3 6% 8% 46%	1672
	11th to 20th	Night	10% 6% 3 6% 4 4 4 4 6% 8% 45%	1688
	21st to end	Night	9% 5% 2 5% 5% 4 5% 4 6% 9% 46%	2066
September	1st to 10th	Night	11% 6% 3 6% 4 3 4 3 6% 7% 47%	1800
	11th to 20th	Night	13% 3 2 4 4 3 3 4 5% 8% 51%	1800
	21st to end	Night	16% 6% 2 6% 4 3 4 4 5% 8% 43%	2056
October	1st to 10th	Night	16% 8% 3 8% 5% 5% 4 3 5% 7% 36%	2160
	11th to 20th	Night	20% 8% 3 8% 5% 5% 4 4 4 7% 33%	2160
	21st to end	Night	22% 9% 3 9% 5% 5% 5% 4 5% 6% 29%	2443
November	1st to 10th	Night	18% 8% 3 6% 4 4 4 3 5% 7% 38%	2411
	11th to 20th	Night	18% 9% 2 7% 5% 4 5% 4 5% 7% 33%	2660
	21st to end	Night	22% 10% 3 6% 5% 4 5% 5% 6% 7% 26%	2660
December	1st to 10th	Night	21% 15% 4 8% 5% 5% 5% 3 6% 6% 23%	2660
	11th to 20th	Night	20% 14% 4 8% 5% 4 3 3 5% 5% 29%	3288
	21st to end	Night	31% 14% 3 8% 5% 4 4 4 5% 5% 18%	4884

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	38% 43% 8% 5% 5% 2	2518
	11th to 20th	Day	52% 40% 2 3 2	2520
	21st to end	Day	45% 41% 7% 5% 2 1	3069
February	1st to 10th	Day	23% 65% 4 6% 2 1	1710
	11th to 20th	Day	19% 64% 3 8% 5%	1672
	21st to end	Day	19% 66% 5% 5% 5% 1	1546
March	1st to 10th	Day	33% 43% 5% 13% 6% 1	3242
	11th to 20th	Day	28% 42% 11% 9% 8% 1	3480
	21st to end	Day	23% 41% 6% 18% 10% 2	3941
April	1st to 10th	Day	21% 65% 3 5% 5% 1	2280
	11th to 20th	Day	17% 66% 2 8% 6% 1	2254
	21st to end	Day	17% 66% 4 8% 5% 1	2389
May	1st to 10th	Day	31% 43% 6% 15% 5%	4372
	11th to 20th	Day	33% 43% 9% 12% 3	4402
	21st to end	Day	21% 42% 8% 19% 9% 1	4837
June	1st to 10th	Day	16% 66% 4 8% 6% 1	2660
	11th to 20th	Day	14% 66% 5% 8% 6% 1	2660
	21st to end	Day	14% 63% 4 11% 7% 1	2660
July	1st to 10th	Day	24% 36% 10% 19% 10% 1	4370
	11th to 20th	Day	21% 37% 10% 26% 6%	4365
	21st to end	Day	23% 38% 11% 21% 8%	4661
August	1st to 10th	Day	14% 62% 8% 11% 5% 1	2468
	11th to 20th	Day	16% 62% 7% 11% 4	2428
	21st to end	Day	13% 62% 7% 13% 5%	2486
September	1st to 10th	Day	12% 64% 7% 11% 5%	2160
	11th to 20th	Day	9% 64% 5% 12% 10%	2160
	21st to end	Day	14% 63% 5% 12% 5%	1900
October	1st to 10th	Day	18% 63% 5% 8% 5%	1800
	11th to 20th	Day	17% 64% 7% 9% 3	1800
	21st to end	Day	22% 62% 4 9% 3	1911
November	1st to 10th	Day	23% 60% 6% 6% 5%	1664
	11th to 20th	Day	20% 61% 5% 10% 3	1520
	21st to end	Day	24% 61% 5% 5% 5%	1520
December	1st to 10th	Day	28% 61% 5% 3 3	1520
	11th to 20th	Day	33% 51% 7% 6% 3	1906
	21st to end	Day	44% 40% 5% 9% 2	2772
January	1st to 10th	Night	41% 43% 6% 7% 3	4429
	11th to 20th	Night	47% 41% 6% 4 2	4440
	21st to end	Night	46% 43% 3 6% 2	4583
February	1st to 10th	Night	23% 66% 4 6% 2	2470
	11th to 20th	Night	19% 64% 5% 7% 5%	2405
	21st to end	Night	19% 65% 4 7% 5%	1907
March	1st to 10th	Night	31% 42% 4 15% 7%	3608
	11th to 20th	Night	36% 41% 8% 8% 6%	3480
	21st to end	Night	23% 41% 3 17% 14% 2	3690
April	1st to 10th	Night	19% 66% 3 7% 5%	1900
	11th to 20th	Night	16% 66% 3 6% 9% 1	1875
	21st to end	Night	17% 65% 4 6% 6% 1	1807
May	1st to 10th	Night	35% 42% 7% 10% 5% 1	2586
	11th to 20th	Night	32% 43% 9% 12% 3	2496
	21st to end	Night	22% 43% 7% 13% 14% 1	2739
June	1st to 10th	Night	15% 65% 3 9% 7% 1	1520
	11th to 20th	Night	15% 65% 3 8% 9% 1	1520
	21st to end	Night	17% 63% 3 8% 8% 1	1520
July	1st to 10th	Night	29% 36% 8% 15% 12% 1	2480
	11th to 20th	Night	24% 36% 8% 25% 8%	2472
	21st to end	Night	23% 37% 11% 20% 8% 1	2651
August	1st to 10th	Night	13% 61% 7% 13% 6%	1662
	11th to 20th	Night	16% 62% 7% 11% 4	1688
	21st to end	Night	13% 61% 6% 14% 6%	2066
September	1st to 10th	Night	12% 64% 6% 13% 5% 1	1800
	11th to 20th	Night	12% 63% 4 12% 9% 1	1800
	21st to end	Night	14% 63% 4 12% 6%	2056
October	1st to 10th	Night	18% 63% 4 8% 6% 1	2160
	11th to 20th	Night	17% 64% 6% 10% 3 1	2160
	21st to end	Night	22% 63% 5% 7% 4	2443
November	1st to 10th	Night	22% 59% 6% 7% 5%	2411
	11th to 20th	Night	20% 61% 5% 9% 5%	2660
	21st to end	Night	23% 61% 5% 6% 4	2660
December	1st to 10th	Night	25% 61% 5% 7% 2	2660
	11th to 20th	Night	31% 51% 6% 8% 4 1	3288
	21st to end	Night	44% 39% 7% 8% 2	4884

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% 13% 24% 28% 8% 2	180
	11th to 20th	Day	30% 13% 29% 20% 8% 1	180
	21st to end	Day	20% 11% 33% 27% 7% 2	283
February	1st to 10th	Day	27% 11% 37% 20% 5%	270
	11th to 20th	Day	20% 12% 35% 29% 4	270
	21st to end	Day	28% 14% 29% 25% 4	358
March	1st to 10th	Day	22% 7% 27% 37% 7% 1	460
	11th to 20th	Day	20% 12% 29% 30% 8%	460
	21st to end	Day	27% 8% 31% 22% 10% 2	506
April	1st to 10th	Day	23% 8% 28% 30% 10% 1	460
	11th to 20th	Day	24% 8% 28% 23% 13% 4	452
	21st to end	Day	25% 5% 25% 30% 13% 2	460
May	1st to 10th	Day	22% 5% 21% 33% 17% 3	463
	11th to 20th	Day	15% 3 21% 36% 20% 5%	487
	21st to end	Day	14% 2 20% 34% 20% 8%	529
June	1st to 10th	Day	16% 5% 19% 36% 21% 3	490
	11th to 20th	Day	13% 3 22% 34% 23% 5%	490
	21st to end	Day	18% 4 21% 34% 20% 4	490
July	1st to 10th	Day	12% 2 14% 35% 30% 6%	485
	11th to 20th	Day	12% 2 17% 33% 30% 6%	484
	21st to end	Day	11% 3 16% 40% 24% 5%	532
August	1st to 10th	Day	13% 2 12% 35% 31% 7%	486
	11th to 20th	Day	12% 3 14% 33% 27% 10%	479
	21st to end	Day	11% 4 18% 37% 21% 9%	532
September	1st to 10th	Day	12% 3 19% 32% 25% 9%	450
	11th to 20th	Day	12% 3 16% 29% 24% 16%	450
	21st to end	Day	14% 5% 21% 31% 22% 7%	450
October	1st to 10th	Day	22% 6% 28% 19% 17% 8%	450
	11th to 20th	Day	22% 10% 27% 25% 14% 2	450
	21st to end	Day	30% 10% 24% 26% 9%	460
November	1st to 10th	Day	21% 11% 27% 28% 12% 1	358
	11th to 20th	Day	19% 15% 31% 24% 8% 3	180
	21st to end	Day	22% 13% 37% 18% 8% 1	180
December	1st to 10th	Day	24% 17% 26% 26% 6% 2	180
	11th to 20th	Day	22% 19% 34% 18% 6% 1	180
	21st to end	Day	32% 13% 32% 20% 3	198
January	1st to 10th	Night	28% 12% 33% 21% 6% 1	760
	11th to 20th	Night	28% 12% 30% 23% 7% 1	760
	21st to end	Night	23% 8% 32% 29% 8%	836
February	1st to 10th	Night	23% 11% 36% 26% 4	760
	11th to 20th	Night	20% 10% 36% 28% 6%	743
	21st to end	Night	22% 8% 37% 28% 5%	628
March	1st to 10th	Night	21% 7% 30% 36% 7%	760
	11th to 20th	Night	25% 8% 29% 30% 8% 1	760
	21st to end	Night	21% 6% 31% 31% 11% 1	836
April	1st to 10th	Night	24% 6% 28% 33% 8%	760
	11th to 20th	Night	22% 5% 33% 26% 12% 2	751
	21st to end	Night	23% 6% 23% 32% 15% 1	667
May	1st to 10th	Night	24% 3 19% 34% 16% 3	420
	11th to 20th	Night	14% 2 20% 44% 18% 2	374
	21st to end	Night	12% 1 24% 39% 20% 5%	411
June	1st to 10th	Night	17% 2 19% 39% 21% 2	380
	11th to 20th	Night	12% 3 19% 39% 24% 3	380
	21st to end	Night	16% 4 20% 37% 22% 1	380
July	1st to 10th	Night	8% 3 17% 39% 30% 2	370
	11th to 20th	Night	12% 3 15% 37% 29% 4	368
	21st to end	Night	11% 1 13% 48% 23% 3	416
August	1st to 10th	Night	11% 2 14% 39% 28% 5%	538
	11th to 20th	Night	14% 2 14% 33% 29% 7%	564
	21st to end	Night	10% 3 17% 39% 27% 4	818
September	1st to 10th	Night	14% 3 19% 35% 23% 6%	720
	11th to 20th	Night	14% 4 16% 28% 29% 9%	720
	21st to end	Night	19% 5% 21% 27% 23% 5%	720
October	1st to 10th	Night	22% 8% 25% 22% 18% 5%	720
	11th to 20th	Night	24% 10% 26% 27% 12% 1	720
	21st to end	Night	26% 11% 28% 27% 8%	792
November	1st to 10th	Night	24% 8% 26% 27% 13% 1	740
	11th to 20th	Night	23% 12% 32% 24% 9% 1	760
	21st to end	Night	28% 12% 30% 22% 8% 1	760
December	1st to 10th	Night	30% 14% 31% 19% 6%	760
	11th to 20th	Night	26% 14% 35% 21% 4 1	760
	21st to end	Night	33% 11% 33% 19% 4	836

Page generated at 2024-08-27 09:49:38. Version ac07

Copyright © 2024 Attilla Danko.