Orion Acres
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Orion Acres 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	13% 8% 3 7% 5% 5% 5% 4 6% 7% 37%	101207
	Night	13% 8% 3 6% 4 4 4 4 5% 7% 41%	98554
Transparency	Day	42% 7% 11% 21% 16% 4	104987
	Night	39% 6% 11% 21% 17% 5%	102912
Seeing	Day	19% 12% 24% 22% 16% 7%	14756
	Night	17% 10% 22% 28% 19% 4	24792

By Month

Percentage Cloud Cover SE (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% 12% 6% 7% 5% 4 3 4 6% 5% 31%	2836
	11th to 20th	Day	20% 8% 4 12% 4 3 3 3 3 4 35%	2840
	21st to end	Day	23% 10% 4 6% 4 3 3 3 4 5% 35%	3324
February	1st to 10th	Day	18% 12% 4 7% 3 4 4 4 4 5% 34%	1900
	11th to 20th	Day	22% 9% 3 7% 5% 4 4 3 5% 4 34%	1848
	21st to end	Day	19% 11% 3 8% 4 4 4 3 5% 5% 34%	1570
March	1st to 10th	Day	23% 12% 4 8% 4 4 3 3 5% 5% 29%	3120
	11th to 20th	Day	14% 8% 3 7% 4 3 3 3 4 5% 47%	3439
	21st to end	Day	16% 9% 3 8% 5% 5% 4 4 5% 7% 35%	3836
April	1st to 10th	Day	12% 9% 2 6% 5% 4 4 4 6% 7% 40%	2280
	11th to 20th	Day	14% 8% 3 6% 4 4 4 4 4 7% 42%	2254
	21st to end	Day	13% 7% 3 6% 5% 5% 4 3 6% 7% 40%	2376
May	1st to 10th	Day	15% 7% 3 6% 5% 4 5% 4 6% 7% 36%	4082
	11th to 20th	Day	17% 8% 3 8% 5% 6% 4 4 6% 8% 32%	4081
	21st to end	Day	11% 7% 2 7% 6% 5% 5% 5% 6% 8% 39%	4476
June	1st to 10th	Day	10% 7% 2 8% 6% 7% 6% 5% 7% 9% 34%	2470
	11th to 20th	Day	5% 5% 2 7% 5% 5% 6% 6% 8% 10% 41%	2470
	21st to end	Day	7% 6% 2 7% 7% 5% 7% 5% 9% 10% 37%	2470
July	1st to 10th	Day	6% 6% 2 8% 8% 7% 7% 6% 8% 11% 30%	4120
	11th to 20th	Day	10% 6% 3 7% 6% 7% 7% 6% 8% 10% 29%	4120
	21st to end	Day	15% 11% 4 11% 7% 7% 7% 5% 7% 8% 18%	4466
August	1st to 10th	Day	5% 4 2 5% 5% 6% 6% 5% 8% 10% 43%	4042
	11th to 20th	Day	6% 4 2 7% 5% 7% 7% 6% 8% 10% 36%	3729
	21st to end	Day	7% 4 2 6% 5% 5% 6% 5% 6% 7% 46%	4180
September	1st to 10th	Day	12% 5% 2 8% 5% 6% 7% 5% 5% 7% 36%	2182
	11th to 20th	Day	13% 7% 3 8% 5% 4 4 5% 6% 7% 38%	2090
	21st to end	Day	13% 6% 2 6% 5% 5% 5% 3 5% 6% 44%	2090
October	1st to 10th	Day	10% 5% 2 6% 3 4 4 3 4 6% 52%	2090
	11th to 20th	Day	12% 5% 2 4 3 4 3 3 5% 6% 54%	2045
	21st to end	Day	14% 6% 3 4 4 3 4 3 6% 6% 48%	1960
November	1st to 10th	Day	11% 6% 2 6% 4 3 3 3 4 4 53%	1762
	11th to 20th	Day	13% 7% 2 7% 4 4 3 3 5% 6% 47%	1800
	21st to end	Day	15% 9% 2 6% 3 4 4 4 5% 6% 42%	1800
December	1st to 10th	Day	20% 11% 4 7% 4 4 4 3 4 5% 35%	1782
	11th to 20th	Day	13% 10% 3 9% 5% 5% 5% 3 4 5% 37%	2153
	21st to end	Day	17% 11% 7% 7% 4 3 4 3 5% 8% 31%	3124
January	1st to 10th	Night	16% 14% 4 7% 4 3 3 3 4 6% 36%	4109
	11th to 20th	Night	18% 12% 4 8% 5% 3 4 2 4 4 36%	4120
	21st to end	Night	21% 14% 5% 6% 4 3 3 2 3 4 35%	4330
February	1st to 10th	Night	17% 9% 4 7% 5% 4 4 3 5% 5% 37%	2280
	11th to 20th	Night	21% 10% 3 7% 5% 4 5% 3 4 3 35%	2218
	21st to end	Night	23% 11% 3 7% 3 4 4 3 4 5% 32%	1884
March	1st to 10th	Night	24% 12% 3 7% 5% 4 4 3 5% 5% 28%	3733
	11th to 20th	Night	11% 9% 2 5% 4 4 4 3 5% 6% 46%	3518
	21st to end	Night	14% 9% 3 8% 6% 5% 5% 3 4 5% 38%	3817
April	1st to 10th	Night	13% 6% 2 5% 4 4 5% 4 5% 7% 45%	1905
	11th to 20th	Night	13% 7% 3 5% 3 2 3 3 5% 8% 47%	1875
	21st to end	Night	11% 7% 2 5% 4 4 4 4 6% 8% 45%	1801
May	1st to 10th	Night	13% 8% 3 6% 5% 4 5% 4 6% 7% 39%	2813
	11th to 20th	Night	17% 8% 3 8% 4 5% 4 3 4 7% 37%	2812
	21st to end	Night	7% 6% 3 8% 4 5% 5% 4 7% 11% 41%	3079
June	1st to 10th	Night	9% 6% 3 8% 6% 5% 5% 3 7% 9% 40%	1710
	11th to 20th	Night	4 3 1 4 3 4 5% 4 7% 12% 53%	1710
	21st to end	Night	5% 5% 2 6% 4 5% 4 5% 8% 12% 45%	1710
July	1st to 10th	Night	8% 5% 2 7% 5% 5% 7% 6% 8% 11% 36%	2840
	11th to 20th	Night	10% 5% 2 4 4 4 5% 5% 8% 11% 43%	2840
	21st to end	Night	12% 13% 4 9% 5% 6% 7% 5% 7% 8% 24%	3087
August	1st to 10th	Night	3 3 1 4 4 5% 5% 4 8% 12% 52%	2882
	11th to 20th	Night	5% 5% 1 6% 5% 5% 4 5% 7% 10% 47%	3100
	21st to end	Night	6% 3 1 4 4 3 4 5% 7% 9% 54%	3476
September	1st to 10th	Night	9% 6% 2 6% 4 5% 5% 4 6% 8% 45%	1977
	11th to 20th	Night	13% 6% 2 5% 4 5% 4 4 7% 7% 43%	2090
	21st to end	Night	10% 6% 2 4 3 4 4 3 6% 6% 51%	2090
October	1st to 10th	Night	10% 4 1 4 3 3 3 2 4 6% 60%	2090
	11th to 20th	Night	12% 6% 2 6% 4 3 4 3 4 5% 51%	2133
	21st to end	Night	14% 8% 2 5% 3 3 3 2 3 6% 51%	2634
November	1st to 10th	Night	13% 7% 2 6% 3 3 4 3 5% 6% 49%	2536
	11th to 20th	Night	12% 9% 2 6% 3 3 3 2 6% 5% 48%	2600
	21st to end	Night	15% 10% 3 6% 4 3 3 3 5% 5% 42%	2600
December	1st to 10th	Night	20% 9% 4 7% 4 5% 4 3 4 6% 34%	2581
	11th to 20th	Night	16% 8% 4 7% 4 3 3 4 5% 6% 40%	3042
	21st to end	Night	17% 9% 6% 9% 5% 5% 5% 4 6% 6% 27%	4532

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	50% 6% 7% 19% 17% 2	2837
	11th to 20th	Day	51% 5% 7% 14% 21% 1	2840
	21st to end	Day	50% 4 8% 22% 15% 2	3324
February	1st to 10th	Day	51% 4 7% 18% 17% 3	1900
	11th to 20th	Day	52% 4 7% 17% 15% 4	1858
	21st to end	Day	50% 4 8% 14% 18% 5%	1570
March	1st to 10th	Day	54% 7% 7% 11% 13% 8%	3120
	11th to 20th	Day	40% 4 8% 23% 18% 7%	3439
	21st to end	Day	47% 7% 9% 23% 12% 2	3836
April	1st to 10th	Day	41% 7% 11% 21% 17% 3	2280
	11th to 20th	Day	41% 6% 8% 19% 22% 4	2254
	21st to end	Day	41% 6% 10% 28% 14% 2	2376
May	1st to 10th	Day	43% 9% 11% 24% 11% 2	4120
	11th to 20th	Day	46% 10% 13% 22% 8%	4085
	21st to end	Day	40% 9% 11% 22% 17% 1	4489
June	1st to 10th	Day	41% 9% 15% 21% 12% 1	2470
	11th to 20th	Day	33% 9% 18% 23% 14% 2	2470
	21st to end	Day	37% 11% 19% 17% 13% 3	2470
July	1st to 10th	Day	43% 9% 20% 20% 7% 1	4055
	11th to 20th	Day	45% 8% 21% 19% 5% 2	4051
	21st to end	Day	61% 9% 12% 14% 4	4324
August	1st to 10th	Day	32% 7% 13% 34% 13% 1	4029
	11th to 20th	Day	38% 7% 16% 23% 14% 1	3765
	21st to end	Day	34% 6% 11% 31% 16% 2	4179
September	1st to 10th	Day	43% 9% 12% 16% 15% 5%	2182
	11th to 20th	Day	43% 7% 10% 19% 18% 2	2090
	21st to end	Day	38% 7% 11% 21% 18% 6%	2090
October	1st to 10th	Day	25% 3 5% 17% 37% 13%	3480
	11th to 20th	Day	22% 2 6% 21% 33% 16%	3376
	21st to end	Day	31% 2 7% 24% 25% 11%	3210
November	1st to 10th	Day	34% 4 7% 20% 27% 7%	1762
	11th to 20th	Day	38% 4 6% 22% 24% 7%	1800
	21st to end	Day	41% 4 8% 21% 22% 5%	1800
December	1st to 10th	Day	52% 4 6% 20% 15% 3	1782
	11th to 20th	Day	47% 5% 9% 17% 19% 4	2150
	21st to end	Day	49% 5% 11% 19% 12% 3	3124
January	1st to 10th	Night	48% 5% 6% 21% 18% 2	4109
	11th to 20th	Night	50% 4 7% 16% 16% 7%	4120
	21st to end	Night	54% 3 6% 15% 18% 3	4330
February	1st to 10th	Night	47% 4 10% 18% 17% 3	2280
	11th to 20th	Night	53% 5% 6% 16% 15% 5%	2219
	21st to end	Night	53% 5% 7% 15% 15% 5%	1884
March	1st to 10th	Night	54% 7% 8% 12% 13% 5%	3733
	11th to 20th	Night	37% 6% 8% 23% 16% 10%	3518
	21st to end	Night	46% 6% 8% 21% 17% 2	3817
April	1st to 10th	Night	36% 7% 11% 22% 21% 3	1905
	11th to 20th	Night	34% 5% 10% 22% 23% 7%	1875
	21st to end	Night	36% 6% 13% 27% 17% 2	1801
May	1st to 10th	Night	40% 10% 14% 23% 13% 1	2840
	11th to 20th	Night	44% 9% 14% 21% 12%	2813
	21st to end	Night	32% 11% 16% 26% 14% 1	3087
June	1st to 10th	Night	39% 8% 16% 22% 12% 3	1710
	11th to 20th	Night	22% 8% 21% 32% 15% 2	1710
	21st to end	Night	30% 9% 19% 25% 13% 4	1710
July	1st to 10th	Night	38% 10% 23% 21% 7% 1	2795
	11th to 20th	Night	32% 7% 26% 26% 7% 3	2786
	21st to end	Night	55% 9% 14% 15% 6% 1	2988
August	1st to 10th	Night	24% 7% 14% 39% 15% 1	2871
	11th to 20th	Night	30% 8% 22% 24% 15% 1	3130
	21st to end	Night	26% 7% 14% 32% 20% 1	3476
September	1st to 10th	Night	33% 10% 16% 20% 15% 5%	1977
	11th to 20th	Night	38% 8% 12% 19% 21% 2	2090
	21st to end	Night	33% 5% 12% 24% 21% 6%	2090
October	1st to 10th	Night	19% 3 6% 24% 31% 17%	3480
	11th to 20th	Night	22% 3 5% 20% 32% 19%	3541
	21st to end	Night	27% 2 6% 26% 28% 11%	4334
November	1st to 10th	Night	35% 5% 8% 20% 24% 8%	2536
	11th to 20th	Night	36% 4 7% 20% 26% 8%	2600
	21st to end	Night	43% 3 6% 21% 21% 5%	2600
December	1st to 10th	Night	50% 5% 7% 17% 17% 3	2581
	11th to 20th	Night	42% 6% 8% 17% 23% 4	3044
	21st to end	Night	52% 6% 10% 19% 11% 2	4532

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	37% 19% 30% 12% 2	270
	11th to 20th	Day	39% 22% 26% 9% 3 1	270
	21st to end	Day	28% 29% 32% 9% 2	297
February	1st to 10th	Day	34% 23% 30% 11% 3	270
	11th to 20th	Day	45% 22% 25% 6% 1	270
	21st to end	Day	44% 25% 26% 4 1	225
March	1st to 10th	Day	32% 20% 34% 11% 1 1	270
	11th to 20th	Day	28% 24% 25% 18% 5% 1	432
	21st to end	Day	26% 21% 31% 15% 7% 1	506
April	1st to 10th	Day	27% 15% 28% 19% 10% 1	460
	11th to 20th	Day	21% 17% 31% 20% 10% 1	452
	21st to end	Day	22% 14% 31% 20% 11% 2	460
May	1st to 10th	Day	17% 16% 31% 21% 10% 5%	463
	11th to 20th	Day	14% 9% 28% 26% 16% 8%	487
	21st to end	Day	15% 8% 22% 27% 15% 13%	529
June	1st to 10th	Day	14% 8% 19% 25% 20% 13%	490
	11th to 20th	Day	6% 5% 17% 32% 24% 17%	490
	21st to end	Day	8% 5% 25% 27% 19% 16%	490
July	1st to 10th	Day	10% 3 17% 28% 25% 17%	485
	11th to 20th	Day	10% 5% 12% 27% 26% 21%	484
	21st to end	Day	11% 4 11% 27% 27% 19%	532
August	1st to 10th	Day	11% 4 16% 26% 26% 17%	486
	11th to 20th	Day	11% 4 19% 28% 28% 9%	479
	21st to end	Day	13% 4 10% 26% 32% 15%	539
September	1st to 10th	Day	10% 4 17% 26% 31% 12%	490
	11th to 20th	Day	14% 5% 17% 27% 28% 10%	490
	21st to end	Day	16% 7% 17% 28% 28% 5%	490
October	1st to 10th	Day	13% 8% 21% 32% 19% 8%	490
	11th to 20th	Day	14% 14% 28% 27% 14% 3	490
	21st to end	Day	20% 10% 31% 23% 14% 2	409
November	1st to 10th	Day	21% 13% 34% 21% 10% 2	300
	11th to 20th	Day	18% 19% 39% 21% 4	300
	21st to end	Day	23% 18% 35% 16% 8% 1	300
December	1st to 10th	Day	34% 17% 31% 15% 3 1	294
	11th to 20th	Day	25% 23% 29% 16% 7%	270
	21st to end	Day	35% 18% 32% 12% 3	297
January	1st to 10th	Night	26% 19% 29% 22% 4	760
	11th to 20th	Night	26% 19% 29% 21% 5%	760
	21st to end	Night	22% 19% 33% 24% 3	836
February	1st to 10th	Night	22% 17% 31% 25% 5%	760
	11th to 20th	Night	29% 20% 28% 21% 2	743
	21st to end	Night	31% 20% 27% 20% 2	628
March	1st to 10th	Night	22% 16% 32% 26% 4	760
	11th to 20th	Night	21% 17% 30% 25% 7% 1	760
	21st to end	Night	19% 15% 30% 27% 8%	836
April	1st to 10th	Night	17% 13% 28% 31% 10%	575
	11th to 20th	Night	18% 12% 31% 27% 11% 1	563
	21st to end	Night	15% 9% 28% 33% 14% 1	570
May	1st to 10th	Night	11% 8% 30% 30% 20% 2	570
	11th to 20th	Night	14% 7% 20% 32% 22% 5%	561
	21st to end	Night	10% 5% 12% 37% 31% 6%	617
June	1st to 10th	Night	9% 5% 15% 35% 31% 5%	570
	11th to 20th	Night	5% 1 11% 33% 38% 12%	570
	21st to end	Night	7% 2 11% 35% 36% 9%	570
July	1st to 10th	Night	10% 1 10% 27% 42% 10%	555
	11th to 20th	Night	9% 4 7% 26% 39% 14%	552
	21st to end	Night	9% 2 7% 29% 41% 12%	624
August	1st to 10th	Night	8% 2 8% 26% 47% 10%	567
	11th to 20th	Night	10% 3 11% 33% 35% 8%	564
	21st to end	Night	12% 1 7% 29% 42% 9%	627
September	1st to 10th	Night	12% 2 10% 31% 37% 8%	647
	11th to 20th	Night	15% 4 14% 27% 34% 6%	760
	21st to end	Night	13% 3 15% 31% 34% 4	760
October	1st to 10th	Night	12% 6% 19% 28% 28% 8%	760
	11th to 20th	Night	16% 9% 24% 31% 19% 2	760
	21st to end	Night	18% 9% 21% 34% 15% 3	836
November	1st to 10th	Night	17% 9% 23% 32% 18% 2	780
	11th to 20th	Night	17% 14% 28% 29% 10% 1	800
	21st to end	Night	21% 13% 25% 30% 10% 1	800
December	1st to 10th	Night	26% 14% 26% 28% 6%	795
	11th to 20th	Night	22% 13% 28% 28% 8% 1	760
	21st to end	Night	27% 16% 25% 28% 5%	836

Page generated at 2024-12-06 02:54:53. Version ac07

Copyright © 2024 Attilla Danko.