The Loose Rooster Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Loose Rooster Observatory clear sky chart from 2005-11-06 to 2024-04-25.

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	16% 10% 4 7% 6% 3 5% 5% 5% 7% 32%	83269
	Night	16% 10% 4 7% 6% 3 5% 4 5% 6% 34%	85831
Transparency	Day	51% 5% 11% 21% 11% 1	82975
	Night	51% 5% 11% 21% 11% 1	85659
Seeing	Day	25% 18% 28% 18% 9% 3	14074
	Night	22% 17% 28% 24% 9% 1	23478

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	14% 13% 11% 10% 6% 3 3 3 3 4 30%	2517
	11th to 20th	Day	13% 15% 8% 13% 7% 4 5% 4 3 5% 22%	2529
	21st to end	Day	20% 15% 8% 8% 7% 3 4 4 4 5% 21%	3124
February	1st to 10th	Day	16% 11% 4 9% 9% 5% 6% 4 5% 6% 25%	1710
	11th to 20th	Day	13% 11% 5% 8% 7% 4 5% 4 5% 8% 30%	1754
	21st to end	Day	18% 11% 3 9% 7% 3 4 4 4 6% 29%	1570
March	1st to 10th	Day	24% 13% 5% 7% 5% 3 4 3 3 5% 27%	3144
	11th to 20th	Day	11% 12% 5% 8% 7% 4 5% 4 4 6% 34%	3480
	21st to end	Day	20% 9% 3 6% 5% 3 4 4 4 6% 36%	4024
April	1st to 10th	Day	18% 12% 4 6% 6% 3 5% 4 4 6% 33%	2280
	11th to 20th	Day	15% 11% 3 6% 5% 3 4 4 5% 6% 36%	2254
	21st to end	Day	17% 9% 4 6% 6% 3 4 5% 6% 6% 35%	2210
May	1st to 10th	Day	20% 9% 3 7% 6% 3 5% 5% 5% 7% 31%	2402
	11th to 20th	Day	19% 7% 3 6% 6% 4 5% 4 6% 6% 33%	2478
	21st to end	Day	15% 7% 2 6% 6% 3 5% 6% 5% 8% 37%	2725
June	1st to 10th	Day	16% 6% 3 7% 6% 4 5% 6% 5% 9% 33%	2520
	11th to 20th	Day	15% 8% 3 6% 6% 4 6% 6% 6% 8% 32%	2520
	21st to end	Day	13% 6% 2 6% 6% 4 5% 5% 7% 9% 36%	2520
July	1st to 10th	Day	12% 6% 2 6% 7% 4 6% 6% 7% 10% 35%	2520
	11th to 20th	Day	9% 5% 3 6% 6% 3 6% 6% 7% 11% 38%	2520
	21st to end	Day	11% 6% 3 6% 6% 4 6% 6% 6% 8% 37%	2736
August	1st to 10th	Day	12% 7% 3 5% 6% 4 7% 7% 8% 9% 33%	2327
	11th to 20th	Day	13% 7% 3 7% 7% 5% 5% 5% 5% 8% 34%	2183
	21st to end	Day	14% 8% 3 6% 6% 3 5% 5% 6% 8% 36%	2376
September	1st to 10th	Day	17% 6% 3 6% 6% 3 4 5% 5% 8% 37%	2160
	11th to 20th	Day	13% 6% 3 5% 5% 3 5% 4 4 7% 45%	2151
	21st to end	Day	16% 7% 3 6% 5% 3 5% 5% 6% 7% 37%	1947
October	1st to 10th	Day	18% 8% 2 6% 5% 3 5% 5% 5% 7% 36%	1800
	11th to 20th	Day	16% 8% 4 6% 6% 4 5% 4 5% 8% 36%	1800
	21st to end	Day	22% 10% 4 6% 5% 4 5% 4 5% 7% 29%	1908
November	1st to 10th	Day	14% 10% 3 6% 5% 2 4 3 4 7% 42%	1671
	11th to 20th	Day	15% 12% 4 7% 6% 2 4 4 4 6% 34%	1691
	21st to end	Day	18% 11% 4 7% 6% 3 4 5% 5% 6% 31%	1520
December	1st to 10th	Day	18% 13% 6% 8% 7% 3 4 4 5% 7% 26%	1520
	11th to 20th	Day	19% 13% 6% 9% 5% 3 3 4 4 6% 28%	1906
	21st to end	Day	19% 17% 8% 9% 6% 3 5% 4 5% 5% 19%	2772
January	1st to 10th	Night	14% 12% 7% 10% 7% 3 5% 4 4 6% 28%	4429
	11th to 20th	Night	12% 15% 6% 13% 9% 3 4 4 4 5% 24%	4426
	21st to end	Night	22% 13% 5% 10% 10% 3 4 5% 4 4 20%	4532
February	1st to 10th	Night	16% 11% 5% 8% 6% 3 5% 4 4 6% 31%	2470
	11th to 20th	Night	14% 11% 5% 9% 7% 4 6% 5% 5% 6% 28%	2311
	21st to end	Night	17% 11% 4 9% 6% 3 4 4 4 5% 32%	1884
March	1st to 10th	Night	21% 14% 5% 8% 5% 3 4 4 4 5% 29%	3692
	11th to 20th	Night	11% 13% 6% 8% 7% 4 4 4 4 6% 33%	3479
	21st to end	Night	14% 12% 4 7% 6% 3 4 4 4 5% 38%	3608
April	1st to 10th	Night	16% 12% 5% 7% 7% 4 4 4 4 6% 31%	1900
	11th to 20th	Night	17% 8% 3 6% 6% 3 4 4 4 7% 37%	1875
	21st to end	Night	19% 8% 3 5% 5% 3 4 4 5% 5% 38%	1850
May	1st to 10th	Night	21% 10% 3 6% 5% 3 5% 3 5% 5% 32%	1572
	11th to 20th	Night	14% 7% 3 6% 6% 3 7% 4 5% 8% 37%	1415
	21st to end	Night	11% 7% 4 7% 6% 3 5% 6% 6% 8% 38%	1550
June	1st to 10th	Night	16% 6% 3 5% 4 3 5% 5% 6% 8% 39%	1440
	11th to 20th	Night	13% 7% 3 6% 5% 3 3 5% 6% 8% 39%	1440
	21st to end	Night	12% 4 1 5% 4 3 5% 5% 6% 9% 46%	1440
July	1st to 10th	Night	12% 6% 3 5% 5% 4 5% 6% 5% 8% 42%	1440
	11th to 20th	Night	10% 5% 3 5% 5% 3 5% 5% 7% 10% 42%	1440
	21st to end	Night	11% 6% 3 4 5% 4 5% 5% 6% 9% 43%	1579
August	1st to 10th	Night	11% 5% 2 6% 5% 3 5% 7% 6% 10% 40%	1611
	11th to 20th	Night	12% 7% 3 6% 6% 4 5% 6% 7% 7% 38%	1699
	21st to end	Night	12% 5% 3 6% 5% 3 5% 4 5% 8% 44%	1980
September	1st to 10th	Night	15% 6% 3 5% 5% 3 5% 5% 5% 7% 42%	1800
	11th to 20th	Night	13% 6% 2 4 4 2 4 4 5% 6% 49%	1808
	21st to end	Night	15% 7% 2 6% 5% 3 3 5% 6% 7% 41%	2010
October	1st to 10th	Night	19% 7% 3 4 3 3 4 4 5% 6% 41%	2160
	11th to 20th	Night	16% 8% 3 5% 5% 4 4 4 5% 5% 41%	2160
	21st to end	Night	22% 10% 3 5% 4 2 5% 4 6% 7% 33%	2448
November	1st to 10th	Night	12% 9% 4 6% 5% 3 4 3 4 6% 43%	2407
	11th to 20th	Night	17% 10% 4 7% 5% 3 4 4 5% 6% 35%	2484
	21st to end	Night	13% 11% 4 6% 5% 3 5% 4 6% 6% 35%	2660
December	1st to 10th	Night	18% 12% 5% 8% 6% 3 5% 5% 6% 6% 25%	2660
	11th to 20th	Night	17% 14% 5% 8% 6% 3 5% 4 4 6% 28%	3288
	21st to end	Night	21% 15% 7% 8% 5% 3 4 4 4 5% 24%	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	59% 4 10% 21% 5% 1	2518
	11th to 20th	Day	66% 4 8% 16% 5% 1	2529
	21st to end	Day	65% 3 10% 16% 5% 1	3124
February	1st to 10th	Day	59% 5% 11% 16% 9% 1	1710
	11th to 20th	Day	54% 5% 8% 22% 10% 1	1763
	21st to end	Day	57% 4 9% 20% 8% 2	1570
March	1st to 10th	Day	61% 4 8% 19% 7% 1	3147
	11th to 20th	Day	49% 5% 12% 24% 9% 1	3480
	21st to end	Day	51% 3 8% 17% 19% 2	4024
April	1st to 10th	Day	54% 4 8% 21% 10% 3	2280
	11th to 20th	Day	48% 5% 10% 22% 13% 2	2254
	21st to end	Day	49% 4 9% 22% 12% 4	2210
May	1st to 10th	Day	54% 5% 8% 19% 12% 3	2402
	11th to 20th	Day	51% 6% 9% 20% 12% 2	2482
	21st to end	Day	44% 6% 15% 20% 12% 2	2725
June	1st to 10th	Day	48% 5% 13% 21% 12% 1	2520
	11th to 20th	Day	49% 5% 13% 21% 10% 1	2520
	21st to end	Day	44% 6% 13% 26% 11%	2520
July	1st to 10th	Day	45% 6% 13% 22% 13% 1	2450
	11th to 20th	Day	37% 6% 16% 26% 14% 1	2445
	21st to end	Day	43% 6% 13% 21% 15% 2	2583
August	1st to 10th	Day	45% 6% 14% 23% 11%	2314
	11th to 20th	Day	47% 6% 14% 23% 10%	2183
	21st to end	Day	46% 4 11% 23% 14% 2	2376
September	1st to 10th	Day	46% 5% 12% 21% 14% 1	2160
	11th to 20th	Day	39% 4 11% 22% 21% 2	2151
	21st to end	Day	45% 5% 10% 23% 16% 2	1947
October	1st to 10th	Day	46% 5% 12% 22% 13% 2	1800
	11th to 20th	Day	47% 5% 11% 24% 13% 1	1800
	21st to end	Day	55% 4 12% 18% 9% 2	1908
November	1st to 10th	Day	44% 4 12% 24% 14% 3	1671
	11th to 20th	Day	51% 4 10% 21% 13% 2	1691
	21st to end	Day	53% 4 14% 21% 7% 1	1520
December	1st to 10th	Day	58% 5% 16% 13% 7% 1	1520
	11th to 20th	Day	59% 4 15% 17% 5%	1906
	21st to end	Day	68% 4 10% 13% 5%	2772
January	1st to 10th	Night	56% 5% 11% 21% 6% 1	4429
	11th to 20th	Night	62% 5% 10% 17% 6% 1	4426
	21st to end	Night	68% 4 7% 15% 6%	4532
February	1st to 10th	Night	54% 5% 12% 20% 9% 1	2470
	11th to 20th	Night	56% 5% 10% 17% 9% 1	2313
	21st to end	Night	55% 4 8% 20% 11% 2	1884
March	1st to 10th	Night	59% 3 9% 18% 10% 1	3702
	11th to 20th	Night	51% 6% 13% 22% 7% 1	3480
	21st to end	Night	49% 4 7% 18% 19% 3	3608
April	1st to 10th	Night	56% 4 9% 19% 12% 2	1900
	11th to 20th	Night	48% 5% 10% 21% 15% 1	1875
	21st to end	Night	47% 5% 10% 21% 14% 3	1850
May	1st to 10th	Night	54% 4 9% 20% 10% 3	1572
	11th to 20th	Night	44% 7% 10% 22% 15% 2	1416
	21st to end	Night	42% 7% 16% 22% 11% 2	1551
June	1st to 10th	Night	43% 5% 11% 26% 14%	1440
	11th to 20th	Night	41% 6% 16% 26% 10% 1	1440
	21st to end	Night	36% 6% 15% 29% 13%	1440
July	1st to 10th	Night	39% 7% 15% 24% 14% 2	1400
	11th to 20th	Night	36% 8% 17% 28% 11% 1	1392
	21st to end	Night	36% 8% 17% 22% 15% 2	1491
August	1st to 10th	Night	38% 6% 16% 28% 12% 1	1600
	11th to 20th	Night	42% 7% 16% 22% 12%	1699
	21st to end	Night	39% 6% 12% 24% 18% 1	1980
September	1st to 10th	Night	41% 6% 13% 24% 15% 1	1800
	11th to 20th	Night	36% 4 10% 26% 22% 2	1808
	21st to end	Night	41% 4 9% 25% 18% 1	2010
October	1st to 10th	Night	44% 4 12% 24% 15% 1	2160
	11th to 20th	Night	44% 5% 14% 25% 11% 1	2160
	21st to end	Night	50% 5% 13% 21% 11% 1	2448
November	1st to 10th	Night	43% 4 12% 22% 17% 3	2407
	11th to 20th	Night	49% 4 11% 21% 12% 3	2484
	21st to end	Night	48% 5% 14% 23% 9% 1	2660
December	1st to 10th	Night	59% 6% 11% 18% 6%	2660
	11th to 20th	Night	57% 6% 12% 17% 8% 1	3288
	21st to end	Night	63% 4 11% 18% 4	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	34% 25% 28% 9% 2 1	180
	11th to 20th	Day	42% 24% 26% 6% 2	184
	21st to end	Day	30% 30% 28% 8% 3 1	297
February	1st to 10th	Day	36% 29% 28% 7%	270
	11th to 20th	Day	36% 27% 29% 7% 1	361
	21st to end	Day	35% 28% 26% 8% 3	382
March	1st to 10th	Day	33% 23% 30% 12% 2	460
	11th to 20th	Day	32% 25% 25% 13% 4 1	460
	21st to end	Day	35% 23% 25% 10% 4 2	506
April	1st to 10th	Day	34% 23% 26% 12% 5%	460
	11th to 20th	Day	29% 23% 29% 11% 6% 2	452
	21st to end	Day	28% 23% 31% 11% 4 2	437
May	1st to 10th	Day	35% 18% 28% 9% 7% 3	423
	11th to 20th	Day	25% 17% 33% 15% 7% 2	447
	21st to end	Day	19% 12% 29% 24% 12% 3	485
June	1st to 10th	Day	20% 15% 29% 23% 10% 3	450
	11th to 20th	Day	20% 17% 25% 24% 13% 1	450
	21st to end	Day	18% 12% 33% 27% 8% 1	450
July	1st to 10th	Day	16% 7% 27% 28% 17% 5%	445
	11th to 20th	Day	9% 7% 31% 32% 17% 4	444
	21st to end	Day	14% 10% 34% 28% 9% 4	488
August	1st to 10th	Day	13% 8% 27% 26% 19% 7%	446
	11th to 20th	Day	15% 8% 26% 29% 16% 6%	439
	21st to end	Day	13% 11% 28% 25% 15% 7%	495
September	1st to 10th	Day	20% 12% 21% 21% 18% 8%	450
	11th to 20th	Day	15% 9% 27% 21% 17% 11%	450
	21st to end	Day	24% 12% 26% 21% 13% 4	450
October	1st to 10th	Day	26% 13% 23% 19% 13% 6%	450
	11th to 20th	Day	23% 17% 30% 21% 8% 1	450
	21st to end	Day	30% 18% 30% 16% 6% 1	459
November	1st to 10th	Day	24% 20% 22% 23% 9% 1	365
	11th to 20th	Day	32% 22% 28% 15% 4 1	351
	21st to end	Day	38% 21% 31% 9% 2	180
December	1st to 10th	Day	36% 26% 26% 8% 3 1	180
	11th to 20th	Day	39% 23% 27% 8% 2	180
	21st to end	Day	31% 29% 28% 10% 2 1	198
January	1st to 10th	Night	24% 26% 34% 12% 3	760
	11th to 20th	Night	28% 23% 29% 18% 3	760
	21st to end	Night	21% 28% 33% 15% 2	836
February	1st to 10th	Night	28% 22% 33% 16% 1	760
	11th to 20th	Night	28% 28% 32% 11% 1	743
	21st to end	Night	29% 25% 30% 14% 2	628
March	1st to 10th	Night	28% 23% 30% 16% 3	760
	11th to 20th	Night	28% 22% 29% 16% 4	760
	21st to end	Night	25% 22% 31% 16% 6%	836
April	1st to 10th	Night	25% 22% 31% 20% 2	760
	11th to 20th	Night	24% 21% 30% 18% 6%	751
	21st to end	Night	26% 17% 27% 25% 5%	740
May	1st to 10th	Night	28% 12% 27% 24% 9%	492
	11th to 20th	Night	17% 10% 36% 29% 6% 1	354
	21st to end	Night	13% 9% 26% 37% 15%	389
June	1st to 10th	Night	16% 8% 23% 38% 14%	360
	11th to 20th	Night	14% 9% 27% 39% 11%	360
	21st to end	Night	13% 5% 25% 47% 9% 1	360
July	1st to 10th	Night	13% 5% 21% 38% 22% 1	350
	11th to 20th	Night	12% 5% 19% 44% 18% 2	348
	21st to end	Night	14% 7% 19% 42% 17% 1	399
August	1st to 10th	Night	12% 3 20% 44% 18% 3	537
	11th to 20th	Night	16% 3 15% 36% 28% 2	635
	21st to end	Night	16% 5% 18% 36% 24% 1	792
September	1st to 10th	Night	17% 6% 22% 35% 17% 3	720
	11th to 20th	Night	16% 7% 21% 30% 21% 6%	720
	21st to end	Night	20% 9% 22% 29% 18% 3	720
October	1st to 10th	Night	24% 9% 22% 26% 17% 1	720
	11th to 20th	Night	19% 15% 29% 30% 8%	720
	21st to end	Night	28% 15% 29% 22% 6%	792
November	1st to 10th	Night	18% 18% 31% 24% 7% 1	740
	11th to 20th	Night	25% 21% 28% 19% 6% 1	760
	21st to end	Night	23% 22% 31% 19% 5% 1	760
December	1st to 10th	Night	29% 21% 30% 15% 4	760
	11th to 20th	Night	26% 25% 28% 18% 3	760
	21st to end	Night	28% 22% 33% 16% 2	836

Page generated at 2024-04-22 09:25:39. Version ac07

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