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 2024-03-06.

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% 6% 2 5% 4 3 4 4 5% 7% 47%	78994
	Night	11% 5% 2 4 4 2 3 4 5% 7% 53%	80579
Transparency	Day	37% 5% 10% 23% 20% 5%	78719
	Night	32% 4 10% 23% 24% 7%	80374
Seeing	Day	17% 11% 28% 27% 14% 3	14323
	Night	16% 12% 30% 29% 12% 1	24375

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% 5% 4 2 3 3 3 6% 48%	2847
	11th to 20th	Day	8% 6% 2 4 4 2 2 2 3 5% 61%	2850
	21st to end	Day	19% 11% 3 5% 3 2 3 3 3 4 45%	3135
February	1st to 10th	Day	19% 8% 3 7% 5% 3 4 3 3 5% 40%	1710
	11th to 20th	Day	17% 7% 3 5% 4 3 4 3 5% 6% 43%	1830
	21st to end	Day	21% 8% 3 5% 3 2 3 3 3 4 43%	1637
March	1st to 10th	Day	16% 7% 2 5% 4 3 3 3 4 5% 47%	2035
	11th to 20th	Day	21% 8% 3 6% 5% 3 3 3 3 4 42%	1980
	21st to end	Day	18% 9% 3 6% 5% 2 3 3 4 6% 40%	2178
April	1st to 10th	Day	14% 6% 3 6% 5% 2 4 3 4 7% 46%	1980
	11th to 20th	Day	18% 5% 2 5% 4 3 4 4 4 6% 45%	2129
	21st to end	Day	19% 7% 3 5% 4 3 4 3 4 6% 41%	2242
May	1st to 10th	Day	16% 7% 2 6% 5% 3 4 4 4 7% 43%	2340
	11th to 20th	Day	15% 6% 3 6% 5% 3 4 5% 6% 6% 41%	2302
	21st to end	Day	15% 6% 3 7% 6% 3 5% 5% 6% 7% 37%	2531
June	1st to 10th	Day	10% 4 2 5% 5% 3 5% 5% 7% 8% 46%	2340
	11th to 20th	Day	9% 4 2 5% 5% 4 5% 6% 7% 10% 44%	2340
	21st to end	Day	6% 3 2 4 4 3 5% 4 7% 8% 55%	2340
July	1st to 10th	Day	8% 5% 2 5% 7% 4 6% 7% 8% 10% 38%	2340
	11th to 20th	Day	4 3 1 4 3 3 6% 5% 7% 10% 53%	2340
	21st to end	Day	6% 3 1 4 5% 3 5% 6% 8% 10% 49%	2546
August	1st to 10th	Day	4 3 2 4 6% 4 6% 6% 7% 8% 51%	2328
	11th to 20th	Day	9% 4 2 5% 4 3 5% 4 6% 9% 48%	2301
	21st to end	Day	5% 3 2 4 5% 4 5% 7% 7% 9% 49%	2412
September	1st to 10th	Day	11% 5% 1 4 4 2 5% 5% 5% 6% 52%	2007
	11th to 20th	Day	11% 5% 2 6% 6% 3 5% 5% 5% 7% 46%	1980
	21st to end	Day	8% 4 1 4 3 3 4 5% 5% 6% 57%	1980
October	1st to 10th	Day	9% 5% 2 4 5% 3 4 5% 4 5% 56%	1864
	11th to 20th	Day	14% 4 2 4 4 2 2 2 3 4 60%	1800
	21st to end	Day	19% 6% 2 3 3 2 3 2 3 4 52%	1980
November	1st to 10th	Day	11% 5% 2 5% 4 2 3 3 4 7% 52%	1858
	11th to 20th	Day	11% 5% 3 4 4 2 2 2 4 5% 59%	1796
	21st to end	Day	17% 6% 2 4 3 2 3 3 4 5% 51%	1710
December	1st to 10th	Day	16% 6% 3 4 2 2 3 3 5% 6% 50%	1710
	11th to 20th	Day	17% 8% 2 5% 5% 3 3 4 4 5% 44%	2161
	21st to end	Day	20% 9% 2 5% 4 2 4 4 5% 6% 40%	3135
January	1st to 10th	Night	12% 7% 3 5% 5% 2 3 4 4 5% 49%	4108
	11th to 20th	Night	8% 5% 2 4 3 2 3 3 4 6% 59%	4120
	21st to end	Night	21% 9% 3 3 3 2 3 3 4 5% 46%	4532
February	1st to 10th	Night	14% 9% 3 5% 4 2 4 4 4 5% 45%	2470
	11th to 20th	Night	15% 8% 4 6% 4 2 3 3 4 5% 47%	2252
	21st to end	Night	16% 8% 3 4 4 2 3 3 3 5% 50%	1814
March	1st to 10th	Night	15% 7% 2 5% 5% 2 3 4 4 5% 48%	2041
	11th to 20th	Night	17% 7% 3 4 4 2 3 3 4 5% 48%	1980
	21st to end	Night	14% 6% 2 5% 4 3 3 5% 4 6% 47%	2178
April	1st to 10th	Night	13% 5% 3 5% 4 2 4 4 5% 7% 49%	1980
	11th to 20th	Night	14% 5% 2 4 3 2 4 4 5% 6% 51%	1779
	21st to end	Night	15% 6% 2 5% 3 2 3 3 4 7% 49%	1713
May	1st to 10th	Night	10% 6% 3 5% 5% 3 4 3 6% 7% 47%	1620
	11th to 20th	Night	12% 5% 2 4 4 3 4 5% 5% 9% 48%	1593
	21st to end	Night	10% 3 2 4 6% 3 4 5% 6% 10% 48%	1745
June	1st to 10th	Night	5% 3 1 3 3 2 3 5% 7% 9% 57%	1620
	11th to 20th	Night	6% 3 2 3 3 2 3 4 7% 10% 59%	1620
	21st to end	Night	4 2 1 2 3 1 3 3 5% 9% 66%	1620
July	1st to 10th	Night	5% 3 2 4 3 2 5% 5% 8% 11% 51%	1620
	11th to 20th	Night	2 2 2 2 1 3 4 6% 10% 67%	1620
	21st to end	Night	3 2 1 3 4 2 3 6% 7% 10% 59%	1772
August	1st to 10th	Night	3 2 1 2 4 2 5% 5% 7% 10% 59%	1611
	11th to 20th	Night	5% 4 2 4 4 2 5% 5% 6% 9% 56%	1600
	21st to end	Night	3 3 2 4 4 3 4 4 6% 9% 59%	1944
September	1st to 10th	Night	7% 5% 2 3 3 2 3 4 4 7% 59%	1948
	11th to 20th	Night	9% 4 1 5% 4 2 4 4 6% 8% 51%	1980
	21st to end	Night	6% 3 1 4 3 2 3 3 5% 7% 64%	1980
October	1st to 10th	Night	7% 4 2 4 4 2 3 4 5% 7% 60%	2076
	11th to 20th	Night	12% 4 2 4 3 2 2 3 4 5% 59%	2160
	21st to end	Night	18% 5% 2 3 3 2 2 2 3 4 56%	2376
November	1st to 10th	Night	11% 4 2 4 3 2 3 3 4 5% 59%	2220
	11th to 20th	Night	8% 5% 3 4 4 3 3 3 3 5% 59%	2379
	21st to end	Night	17% 6% 2 3 3 2 3 3 4 6% 53%	2470
December	1st to 10th	Night	14% 6% 2 4 3 2 4 4 4 7% 51%	2470
	11th to 20th	Night	13% 7% 3 7% 5% 2 3 3 3 5% 49%	3036
	21st to end	Night	18% 9% 2 4 3 2 3 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 8% 18% 19% 11%	2035
	11th to 20th	Day	48% 3 6% 20% 17% 6%	1980
	21st to end	Day	47% 4 8% 22% 16% 3	2178
April	1st to 10th	Day	41% 3 10% 21% 18% 6%	1980
	11th to 20th	Day	41% 4 10% 22% 17% 5%	2129
	21st to end	Day	45% 4 8% 21% 18% 3	2242
May	1st to 10th	Day	43% 4 11% 22% 17% 3	2340
	11th to 20th	Day	42% 6% 13% 23% 15% 1	2306
	21st to end	Day	45% 7% 12% 22% 13% 1	2531
June	1st to 10th	Day	33% 8% 15% 28% 14% 2	2340
	11th to 20th	Day	34% 8% 13% 26% 17% 2	2340
	21st to end	Day	26% 7% 12% 29% 23% 3	2340
July	1st to 10th	Day	36% 9% 19% 23% 13% 1	2276
	11th to 20th	Day	23% 7% 13% 33% 21% 3	2271
	21st to end	Day	26% 9% 17% 34% 15%	2405
August	1st to 10th	Day	27% 8% 15% 28% 21% 2	2314
	11th to 20th	Day	32% 6% 15% 24% 21% 2	2301
	21st to end	Day	28% 8% 16% 29% 16% 3	2412
September	1st to 10th	Day	31% 6% 9% 24% 21% 9%	2007
	11th to 20th	Day	36% 7% 10% 20% 20% 8%	1980
	21st to end	Day	27% 5% 8% 23% 28% 9%	1980
October	1st to 10th	Day	31% 4 11% 19% 24% 11%	1864
	11th to 20th	Day	31% 3 6% 16% 30% 14%	1800
	21st to end	Day	37% 3 7% 19% 24% 9%	1980
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	39% 3 8% 18% 19% 13%	2041
	11th to 20th	Night	41% 3 9% 19% 20% 8%	1980
	21st to end	Night	38% 5% 9% 23% 20% 4	2178
April	1st to 10th	Night	36% 4 10% 20% 20% 11%	1980
	11th to 20th	Night	34% 5% 8% 24% 18% 10%	1779
	21st to end	Night	36% 4 9% 25% 22% 3	1713
May	1st to 10th	Night	36% 5% 10% 24% 18% 7%	1620
	11th to 20th	Night	33% 6% 14% 28% 15% 2	1594
	21st to end	Night	33% 6% 16% 27% 16% 3	1746
June	1st to 10th	Night	21% 8% 16% 32% 20% 3	1620
	11th to 20th	Night	22% 5% 12% 34% 23% 4	1620
	21st to end	Night	18% 5% 13% 29% 29% 6%	1620
July	1st to 10th	Night	25% 8% 17% 28% 20% 2	1575
	11th to 20th	Night	12% 5% 13% 38% 27% 5%	1566
	21st to end	Night	17% 7% 17% 34% 24% 1	1673
August	1st to 10th	Night	18% 6% 15% 33% 23% 4	1601
	11th to 20th	Night	24% 5% 12% 28% 26% 4	1600
	21st to end	Night	22% 5% 16% 30% 22% 4	1944
September	1st to 10th	Night	24% 5% 10% 25% 26% 9%	1948
	11th to 20th	Night	31% 6% 9% 21% 23% 10%	1980
	21st to end	Night	21% 3 9% 25% 31% 12%	1980
October	1st to 10th	Night	25% 4 10% 23% 23% 14%	2076
	11th to 20th	Night	29% 3 6% 16% 29% 18%	2160
	21st to end	Night	35% 3 4 20% 26% 12%	2376
November	1st to 10th	Night	29% 3 7% 24% 26% 10%	2220
	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	30% 21% 34% 13% 2	255
	11th to 20th	Day	37% 22% 30% 9% 3	240
	21st to end	Day	24% 31% 36% 7% 2	264
April	1st to 10th	Day	26% 23% 38% 11% 3	240
	11th to 20th	Day	30% 19% 34% 13% 4	407
	21st to end	Day	25% 21% 36% 13% 4 1	502
May	1st to 10th	Day	20% 15% 43% 18% 3	603
	11th to 20th	Day	17% 11% 39% 22% 9% 2	625
	21st to end	Day	17% 8% 37% 22% 14% 3	679
June	1st to 10th	Day	11% 4 23% 37% 19% 5%	630
	11th to 20th	Day	10% 4 31% 37% 16% 3	630
	21st to end	Day	5% 3 27% 39% 22% 5%	630
July	1st to 10th	Day	8% 1 18% 38% 27% 7%	621
	11th to 20th	Day	4 2 16% 40% 33% 5%	618
	21st to end	Day	4 2 13% 41% 32% 8%	684
August	1st to 10th	Day	6% 2 14% 47% 28% 4	626
	11th to 20th	Day	10% 1 16% 43% 26% 4	615
	21st to end	Day	5% 1 11% 41% 34% 8%	531
September	1st to 10th	Day	7% 1 9% 39% 34% 9%	297
	11th to 20th	Day	6% 2 20% 41% 26% 4	270
	21st to end	Day	14% 6% 20% 39% 18% 3	270
October	1st to 10th	Day	7% 9% 36% 33% 12% 3	270
	11th to 20th	Day	20% 12% 38% 24% 6%	270
	21st to end	Day	34% 13% 27% 21% 5%	297
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	22% 16% 36% 22% 4	557
	11th to 20th	Night	23% 15% 39% 18% 4	540
	21st to end	Night	19% 19% 37% 21% 4 1	594
April	1st to 10th	Night	19% 19% 37% 21% 5%	540
	11th to 20th	Night	19% 17% 35% 24% 5%	533
	21st to end	Night	17% 17% 37% 19% 8% 1	540
May	1st to 10th	Night	14% 13% 37% 29% 8%	540
	11th to 20th	Night	14% 8% 38% 27% 12% 1	531
	21st to end	Night	9% 6% 34% 31% 18% 1	584
June	1st to 10th	Night	7% 3 24% 40% 23% 3	540
	11th to 20th	Night	7% 2 35% 43% 14% 1	540
	21st to end	Night	3 1 25% 42% 25% 4	540
July	1st to 10th	Night	6% 1 16% 42% 31% 5%	525
	11th to 20th	Night	3 1 16% 49% 28% 3	522
	21st to end	Night	4 13% 45% 34% 5%	591
August	1st to 10th	Night	4 1 15% 49% 28% 3	537
	11th to 20th	Night	7% 1 14% 44% 30% 4	534
	21st to end	Night	4 1 13% 44% 33% 4	594
September	1st to 10th	Night	9% 2 14% 43% 30% 3	540
	11th to 20th	Night	11% 2 20% 36% 28% 3	540
	21st to end	Night	7% 2 26% 37% 25% 3	540
October	1st to 10th	Night	9% 6% 32% 30% 20% 3	636
	11th to 20th	Night	15% 10% 32% 29% 12% 1	720
	21st to end	Night	21% 11% 30% 25% 11% 1	792
November	1st to 10th	Night	13% 13% 37% 28% 8% 1	740
	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 2024-03-03 05:29:00. Version ac07

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