Oleo Acres Double Barrel Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oleo Acres Double Barrel Observatory clear sky chart from 2005-11-06 to 2024-11-01.

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	12% 6% 2 6% 4 4 4 3 5% 7% 48%	101201
	Night	11% 6% 2 5% 3 3 3 3 5% 6% 53%	97832
Transparency	Day	36% 5% 10% 24% 20% 5%	101015
	Night	32% 4 10% 24% 23% 7%	97689
Seeing	Day	17% 11% 28% 27% 14% 3	15305
	Night	16% 12% 30% 29% 12% 1	25123

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	12% 9% 5% 6% 3 3 2 3 3 5% 48%	2847
	11th to 20th	Day	8% 6% 2 5% 3 2 2 2 4 5% 61%	2850
	21st to end	Day	19% 11% 3 6% 3 2 3 2 4 4 45%	3135
February	1st to 10th	Day	18% 9% 2 8% 5% 4 4 3 3 5% 40%	1710
	11th to 20th	Day	16% 8% 3 6% 4 4 3 2 5% 6% 43%	1830
	21st to end	Day	21% 9% 3 6% 3 3 3 3 3 4 43%	1637
March	1st to 10th	Day	18% 8% 2 6% 4 3 3 2 4 4 47%	3436
	11th to 20th	Day	15% 8% 2 7% 4 4 3 3 5% 5% 43%	3480
	21st to end	Day	18% 10% 3 7% 4 4 4 3 4 6% 37%	3814
April	1st to 10th	Day	14% 7% 3 7% 4 3 3 3 4 6% 46%	2090
	11th to 20th	Day	18% 5% 2 6% 4 4 4 3 4 5% 45%	2249
	21st to end	Day	19% 8% 2 6% 3 4 3 3 4 6% 41%	2367
May	1st to 10th	Day	21% 8% 2 7% 4 3 4 3 4 6% 39%	4082
	11th to 20th	Day	14% 6% 3 6% 4 4 4 4 5% 6% 44%	4082
	21st to end	Day	20% 7% 3 7% 5% 4 4 3 5% 6% 35%	4477
June	1st to 10th	Day	10% 4 2 5% 4 4 6% 4 7% 8% 45%	2470
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 7% 9% 45%	2470
	21st to end	Day	6% 3 2 4 4 4 4 4 7% 8% 54%	2470
July	1st to 10th	Day	8% 5% 2 5% 5% 4 5% 4 7% 9% 47%	4120
	11th to 20th	Day	3 3 1 5% 3 4 5% 4 7% 9% 56%	4120
	21st to end	Day	6% 5% 2 6% 6% 5% 6% 5% 8% 10% 41%	4465
August	1st to 10th	Day	3 3 1 4 4 4 5% 4 6% 7% 60%	4104
	11th to 20th	Day	7% 3 2 5% 3 4 4 4 6% 10% 53%	4041
	21st to end	Day	3 3 1 4 5% 4 5% 5% 7% 9% 54%	4230
September	1st to 10th	Day	11% 6% 1 4 4 3 5% 4 5% 6% 52%	2118
	11th to 20th	Day	10% 4 2 7% 5% 4 5% 3 5% 7% 47%	2090
	21st to end	Day	8% 4 1 4 3 4 5% 4 5% 6% 57%	2090
October	1st to 10th	Day	8% 4 1 4 4 4 4 4 4 5% 58%	1967
	11th to 20th	Day	13% 4 1 4 3 2 2 2 3 4 61%	1900
	21st to end	Day	18% 6% 2 4 3 3 3 2 4 4 53%	2090
November	1st to 10th	Day	11% 6% 2 6% 3 2 3 3 4 7% 52%	1858
	11th to 20th	Day	11% 5% 3 5% 3 3 3 2 4 5% 59%	1796
	21st to end	Day	17% 7% 2 5% 2 3 2 2 4 5% 51%	1710
December	1st to 10th	Day	16% 6% 3 5% 2 3 3 3 5% 6% 50%	1710
	11th to 20th	Day	17% 8% 2 6% 4 4 4 3 4 5% 44%	2161
	21st to end	Day	19% 9% 2 5% 3 3 4 3 5% 6% 39%	3135
January	1st to 10th	Night	12% 8% 3 6% 4 3 3 3 5% 5% 49%	4108
	11th to 20th	Night	8% 6% 2 4 3 3 3 2 4 6% 59%	4120
	21st to end	Night	21% 9% 3 4 2 2 3 2 4 4 46%	4532
February	1st to 10th	Night	14% 9% 3 6% 3 3 4 3 5% 5% 45%	2470
	11th to 20th	Night	15% 9% 3 6% 3 3 3 3 4 5% 47%	2252
	21st to end	Night	16% 8% 3 4 4 3 2 3 3 5% 50%	1814
March	1st to 10th	Night	18% 9% 2 5% 3 3 4 3 4 5% 43%	3419
	11th to 20th	Night	15% 7% 3 4 3 3 3 3 4 5% 52%	3480
	21st to end	Night	14% 7% 2 6% 4 3 4 3 5% 6% 45%	3817
April	1st to 10th	Night	13% 6% 2 6% 3 3 4 3 5% 7% 49%	2090
	11th to 20th	Night	13% 6% 2 5% 3 3 4 3 5% 6% 50%	1879
	21st to end	Night	15% 7% 2 5% 3 3 3 3 5% 6% 48%	1808
May	1st to 10th	Night	20% 8% 2 5% 4 3 4 3 6% 6% 39%	2823
	11th to 20th	Night	15% 5% 2 5% 4 4 3 3 5% 8% 46%	2823
	21st to end	Night	15% 5% 2 5% 5% 5% 3 4 6% 8% 42%	3090
June	1st to 10th	Night	6% 3 2 4 3 2 4 3 7% 9% 57%	1710
	11th to 20th	Night	5% 3 2 3 3 3 3 3 7% 9% 59%	1710
	21st to end	Night	4 2 1 2 3 2 3 3 6% 9% 65%	1710
July	1st to 10th	Night	8% 4 2 5% 3 4 4 4 6% 8% 53%	2850
	11th to 20th	Night	3 3 1 3 2 2 3 3 5% 8% 68%	2850
	21st to end	Night	4 4 1 5% 4 4 3 4 7% 9% 54%	3098
August	1st to 10th	Night	2 2 1 3 2 2 4 4 5% 7% 68%	2836
	11th to 20th	Night	4 3 1 3 2 3 4 4 5% 9% 63%	2798
	21st to end	Night	2 2 1 3 3 3 3 3 5% 9% 65%	3414
September	1st to 10th	Night	7% 6% 1 4 3 3 4 3 5% 7% 58%	2057
	11th to 20th	Night	9% 4 1 6% 3 3 4 3 6% 8% 52%	2090
	21st to end	Night	6% 3 1 5% 2 3 3 2 5% 7% 62%	2090
October	1st to 10th	Night	6% 4 1 4 3 2 3 3 4 6% 62%	2192
	11th to 20th	Night	12% 4 2 4 2 2 3 2 4 5% 61%	2280
	21st to end	Night	17% 5% 2 4 2 2 2 2 3 4 57%	2508
November	1st to 10th	Night	11% 5% 2 4 3 3 3 2 4 5% 59%	2227
	11th to 20th	Night	8% 6% 2 5% 3 3 4 3 3 4 59%	2379
	21st to end	Night	17% 6% 2 3 2 3 3 2 4 6% 53%	2470
December	1st to 10th	Night	14% 6% 2 5% 2 3 3 3 4 7% 51%	2470
	11th to 20th	Night	12% 7% 3 7% 4 3 3 2 3 4 49%	3036
	21st to end	Night	18% 9% 2 4 3 3 2 2 4 6% 48%	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	40% 3 7% 24% 23% 3	2848
	11th to 20th	Day	28% 3 13% 26% 27% 4	2850
	21st to end	Day	45% 4 4 18% 23% 6%	3135
February	1st to 10th	Day	48% 4 8% 16% 20% 4	1710
	11th to 20th	Day	43% 4 6% 22% 19% 5%	1840
	21st to end	Day	46% 3 4 14% 24% 8%	1637
March	1st to 10th	Day	41% 3 7% 16% 21% 11%	3436
	11th to 20th	Day	43% 4 10% 22% 16% 5%	3480
	21st to end	Day	48% 5% 7% 23% 15% 2	3814
April	1st to 10th	Day	41% 3 10% 20% 19% 7%	2090
	11th to 20th	Day	42% 4 9% 22% 18% 6%	2249
	21st to end	Day	45% 5% 8% 21% 18% 3	2367
May	1st to 10th	Day	47% 5% 9% 21% 16% 3	4120
	11th to 20th	Day	39% 7% 11% 24% 19%	4086
	21st to end	Day	49% 6% 11% 17% 13% 4	4489
June	1st to 10th	Day	33% 8% 15% 28% 14% 2	2470
	11th to 20th	Day	33% 7% 13% 26% 18% 2	2470
	21st to end	Day	26% 7% 14% 29% 22% 3	2470
July	1st to 10th	Day	31% 6% 18% 30% 14% 1	4056
	11th to 20th	Day	22% 6% 10% 39% 21% 2	4051
	21st to end	Day	33% 9% 13% 31% 13%	4325
August	1st to 10th	Day	22% 6% 12% 27% 27% 6%	4090
	11th to 20th	Day	27% 5% 18% 34% 15% 1	4080
	21st to end	Day	24% 7% 16% 37% 13% 2	4229
September	1st to 10th	Day	32% 6% 9% 23% 21% 10%	2118
	11th to 20th	Day	35% 6% 9% 21% 20% 8%	2090
	21st to end	Day	27% 5% 8% 22% 28% 9%	2090
October	1st to 10th	Day	29% 4 10% 18% 26% 12%	1967
	11th to 20th	Day	30% 3 5% 17% 30% 15%	1900
	21st to end	Day	36% 2 8% 20% 25% 9%	2090
November	1st to 10th	Day	34% 3 7% 24% 25% 7%	1858
	11th to 20th	Day	30% 3 7% 25% 27% 8%	1796
	21st to end	Day	37% 2 6% 20% 26% 7%	1710
December	1st to 10th	Day	36% 4 9% 27% 20% 5%	1710
	11th to 20th	Day	43% 3 6% 18% 23% 7%	2159
	21st to end	Day	43% 4 7% 19% 22% 4	3135
January	1st to 10th	Night	37% 4 6% 20% 28% 5%	4108
	11th to 20th	Night	28% 4 15% 20% 27% 6%	4120
	21st to end	Night	43% 3 7% 17% 25% 6%	4532
February	1st to 10th	Night	42% 4 9% 20% 19% 7%	2470
	11th to 20th	Night	41% 3 5% 22% 22% 6%	2252
	21st to end	Night	39% 3 7% 17% 23% 11%	1814
March	1st to 10th	Night	44% 4 7% 16% 17% 12%	3419
	11th to 20th	Night	36% 4 8% 27% 15% 10%	3480
	21st to end	Night	40% 5% 9% 21% 23% 3	3817
April	1st to 10th	Night	36% 4 9% 19% 19% 12%	2090
	11th to 20th	Night	34% 5% 8% 23% 19% 11%	1879
	21st to end	Night	37% 4 9% 25% 22% 3	1808
May	1st to 10th	Night	46% 5% 9% 20% 14% 6%	2850
	11th to 20th	Night	36% 7% 13% 26% 16% 2	2824
	21st to end	Night	38% 8% 14% 22% 12% 6%	3099
June	1st to 10th	Night	22% 8% 16% 32% 19% 3	1710
	11th to 20th	Night	23% 5% 12% 33% 24% 4	1710
	21st to end	Night	17% 5% 13% 30% 28% 6%	1710
July	1st to 10th	Night	27% 6% 17% 30% 16% 4	2805
	11th to 20th	Night	16% 4 9% 44% 24% 3	2796
	21st to end	Night	24% 6% 17% 33% 19% 1	2999
August	1st to 10th	Night	14% 5% 11% 29% 33% 8%	2826
	11th to 20th	Night	19% 4 16% 36% 20% 4	2825
	21st to end	Night	18% 4 16% 38% 21% 3	3414
September	1st to 10th	Night	25% 6% 10% 24% 25% 11%	2057
	11th to 20th	Night	30% 6% 9% 22% 24% 10%	2090
	21st to end	Night	22% 3 9% 25% 30% 11%	2090
October	1st to 10th	Night	24% 4 10% 22% 25% 15%	2192
	11th to 20th	Night	27% 3 5% 16% 30% 18%	2280
	21st to end	Night	34% 3 4 21% 26% 12%	2508
November	1st to 10th	Night	29% 3 7% 24% 26% 10%	2227
	11th to 20th	Night	29% 3 7% 22% 28% 11%	2379
	21st to end	Night	36% 2 7% 21% 27% 7%	2470
December	1st to 10th	Night	33% 4 10% 22% 22% 9%	2470
	11th to 20th	Night	40% 3 6% 18% 26% 8%	3037
	21st to end	Night	40% 3 6% 23% 21% 7%	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	23% 24% 35% 14% 3	270
	11th to 20th	Day	24% 29% 37% 7% 1 1	270
	21st to end	Day	25% 26% 31% 15% 4	297
February	1st to 10th	Day	35% 17% 37% 9% 2	270
	11th to 20th	Day	36% 23% 33% 7% 1	270
	21st to end	Day	41% 26% 27% 5% 1	225
March	1st to 10th	Day	31% 20% 34% 13% 1	270
	11th to 20th	Day	36% 22% 31% 9% 3	270
	21st to end	Day	27% 29% 36% 7% 2	297
April	1st to 10th	Day	29% 22% 37% 10% 2	270
	11th to 20th	Day	31% 19% 34% 13% 3	447
	21st to end	Day	26% 21% 35% 13% 4 1	547
May	1st to 10th	Day	20% 15% 43% 18% 3	653
	11th to 20th	Day	17% 10% 40% 21% 9% 2	675
	21st to end	Day	17% 9% 37% 22% 13% 3	734
June	1st to 10th	Day	11% 4 24% 37% 19% 5%	680
	11th to 20th	Day	9% 4 31% 37% 16% 3	680
	21st to end	Day	5% 3 26% 40% 22% 4	680
July	1st to 10th	Day	8% 2 19% 38% 27% 7%	671
	11th to 20th	Day	4 2 17% 40% 32% 5%	668
	21st to end	Day	5% 2 15% 40% 30% 7%	739
August	1st to 10th	Day	5% 1 13% 47% 28% 4	676
	11th to 20th	Day	10% 2 17% 43% 25% 4	665
	21st to end	Day	5% 1 12% 41% 33% 9%	576
September	1st to 10th	Day	9% 2 10% 39% 32% 8%	328
	11th to 20th	Day	6% 3 24% 40% 24% 4	300
	21st to end	Day	13% 6% 20% 39% 17% 3	300
October	1st to 10th	Day	7% 8% 35% 35% 12% 3	300
	11th to 20th	Day	18% 12% 38% 26% 5%	300
	21st to end	Day	31% 13% 29% 22% 5%	330
November	1st to 10th	Day	14% 17% 40% 21% 5% 2	270
	11th to 20th	Day	18% 21% 36% 19% 4 2	270
	21st to end	Day	29% 19% 36% 13% 3	270
December	1st to 10th	Day	26% 16% 37% 17% 4 1	270
	11th to 20th	Day	30% 19% 37% 10% 4	270
	21st to end	Day	28% 21% 37% 12% 2	297
January	1st to 10th	Night	18% 17% 35% 24% 5%	950
	11th to 20th	Night	23% 17% 35% 20% 4	950
	21st to end	Night	20% 18% 32% 25% 5%	1045
February	1st to 10th	Night	24% 20% 34% 18% 3	950
	11th to 20th	Night	23% 23% 34% 17% 3	778
	21st to end	Night	28% 20% 33% 17% 2	558
March	1st to 10th	Night	23% 15% 36% 22% 4	570
	11th to 20th	Night	22% 16% 40% 18% 4	570
	21st to end	Night	19% 19% 37% 20% 4 1	627
April	1st to 10th	Night	19% 18% 37% 21% 5%	570
	11th to 20th	Night	19% 17% 36% 23% 5%	563
	21st to end	Night	18% 16% 37% 20% 8% 1	570
May	1st to 10th	Night	14% 12% 38% 28% 8%	570
	11th to 20th	Night	14% 7% 37% 28% 12% 1	561
	21st to end	Night	11% 7% 34% 31% 17% 1	617
June	1st to 10th	Night	7% 3 25% 40% 22% 3	570
	11th to 20th	Night	7% 2 34% 42% 14% 1	570
	21st to end	Night	3 1 25% 42% 25% 3	570
July	1st to 10th	Night	5% 1 16% 43% 29% 5%	555
	11th to 20th	Night	3 1 17% 49% 27% 3	552
	21st to end	Night	4 1 14% 44% 33% 5%	624
August	1st to 10th	Night	4 1 15% 48% 29% 3	567
	11th to 20th	Night	7% 1 15% 45% 29% 4	564
	21st to end	Night	4 1 14% 44% 33% 4	627
September	1st to 10th	Night	9% 2 14% 43% 29% 3	570
	11th to 20th	Night	11% 2 21% 37% 26% 3	570
	21st to end	Night	7% 2 26% 37% 24% 3	570
October	1st to 10th	Night	9% 6% 31% 32% 21% 3	672
	11th to 20th	Night	15% 10% 32% 31% 12% 1	760
	21st to end	Night	21% 11% 31% 25% 11% 1	836
November	1st to 10th	Night	13% 13% 37% 28% 8% 1	743
	11th to 20th	Night	14% 14% 35% 27% 8%	859
	21st to end	Night	24% 15% 32% 21% 8%	950
December	1st to 10th	Night	21% 15% 34% 26% 4	950
	11th to 20th	Night	23% 15% 35% 22% 4	950
	21st to end	Night	23% 19% 32% 21% 5%	1045

Page generated at 2024-10-29 10:20:50. Version ac07

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