Oak Canyon Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oak Canyon Park clear sky chart from 2005-11-06 to 2024-11-25.

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	4 3 1 3 2 2 3 3 4 6% 68%	105080
	Night	5% 4 1 4 3 3 3 2 4 6% 66%	103176
Transparency	Day	18% 3 5% 18% 27% 28%	104841
	Night	20% 4 5% 17% 26% 29%	103005
Seeing	Day	6% 7% 22% 32% 23% 9%	15682
	Night	6% 3 11% 35% 37% 9%	25491

By Month

Percentage Cloud Cover SW (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	6% 3 1 4 3 2 3 3 4 6% 67%	2543
	11th to 20th	Day	9% 4 2 5% 3 3 3 3 5% 9% 54%	2860
	21st to end	Day	13% 5% 2 4 3 3 3 3 4 8% 53%	3351
February	1st to 10th	Day	9% 4 2 3 3 2 2 4 4 5% 61%	1900
	11th to 20th	Day	8% 3 1 4 3 3 3 3 5% 7% 61%	1850
	21st to end	Day	7% 4 3 5% 3 4 3 3 5% 6% 57%	1570
March	1st to 10th	Day	9% 5% 2 6% 4 4 4 4 6% 7% 49%	3138
	11th to 20th	Day	5% 3 1 4 2 3 3 3 5% 7% 63%	3325
	21st to end	Day	7% 5% 1 4 4 5% 5% 4 6% 8% 49%	4155
April	1st to 10th	Day	5% 5% 2 4 3 3 3 3 5% 8% 59%	2280
	11th to 20th	Day	4 4 1 4 3 3 3 3 4 6% 65%	2249
	21st to end	Day	4 4 1 3 2 2 2 3 4 6% 68%	2280
May	1st to 10th	Day	2 3 2 3 2 2 3 2 4 6% 71%	3820
	11th to 20th	Day	2 5% 3 5% 3 3 3 3 5% 9% 59%	4071
	21st to end	Day	2 5% 2 5% 3 3 3 3 5% 8% 62%	4477
June	1st to 10th	Day	3 5% 1 5% 3 3 3 3 5% 8% 61%	2581
	11th to 20th	Day	2 4 2 4 2 2 2 2 5% 8% 67%	2660
	21st to end	Day	1 2 1 3 2 2 2 2 3 6% 76%	2660
July	1st to 10th	Day	1 1 1 2 2 2 2 1 3 4 83%	4420
	11th to 20th	Day	1 1 1 2 2 2 2 2 3 4 79%	4358
	21st to end	Day	1 1 1 1 2 2 2 3 4 83%	4210
August	1st to 10th	Day	1 1 1 2 1 1 2 1 3 4 83%	3783
	11th to 20th	Day	1 1 1 1 1 1 1 2 3 88%	3724
	21st to end	Day	1 1 1 1 1 1 2 4 86%	4180
September	1st to 10th	Day	1 2 1 2 2 2 2 2 4 5% 78%	2280
	11th to 20th	Day	1 2 1 2 2 2 2 1 3 4 79%	2176
	21st to end	Day	1 2 1 3 2 2 2 2 3 4 79%	2090
October	1st to 10th	Day	2 1 2 1 1 2 2 3 4 82%	3490
	11th to 20th	Day	2 2 1 4 2 3 2 2 4 6% 71%	3167
	21st to end	Day	2 2 1 4 3 3 3 3 5% 5% 69%	3448
November	1st to 10th	Day	3 2 1 3 2 2 3 2 4 6% 71%	1769
	11th to 20th	Day	4 2 2 3 2 3 3 3 4 6% 70%	1800
	21st to end	Day	4 4 1 5% 3 3 3 3 5% 7% 62%	1746
December	1st to 10th	Day	7% 4 1 4 3 4 3 4 5% 7% 57%	1710
	11th to 20th	Day	15% 8% 2 6% 4 3 3 4 5% 7% 44%	2165
	21st to end	Day	12% 5% 2 6% 5% 5% 4 4 6% 6% 45%	2794
January	1st to 10th	Night	7% 4 2 4 2 3 3 2 3 6% 64%	4397
	11th to 20th	Night	8% 5% 2 6% 4 3 3 3 5% 7% 54%	4110
	21st to end	Night	13% 7% 2 4 3 3 3 3 4 6% 53%	4305
February	1st to 10th	Night	7% 5% 2 4 3 3 2 3 5% 4 62%	2280
	11th to 20th	Night	9% 4 1 4 3 3 3 3 4 5% 62%	2218
	21st to end	Night	10% 5% 1 5% 3 3 3 3 4 6% 57%	1884
March	1st to 10th	Night	7% 8% 2 6% 3 4 4 4 6% 7% 49%	3736
	11th to 20th	Night	4 4 2 5% 4 3 4 3 5% 7% 60%	3650
	21st to end	Night	9% 5% 2 4 3 3 3 2 5% 7% 57%	3497
April	1st to 10th	Night	6% 5% 2 4 3 3 3 3 4 6% 61%	1900
	11th to 20th	Night	3 5% 1 4 3 2 3 3 4 6% 66%	1879
	21st to end	Night	4 4 1 3 3 2 2 2 6% 7% 65%	1900
May	1st to 10th	Night	2 4 1 5% 4 3 3 2 5% 4 68%	3158
	11th to 20th	Night	1 4 2 6% 6% 4 3 4 7% 7% 54%	2834
	21st to end	Night	1 3 2 6% 3 2 2 2 4 4 70%	3110
June	1st to 10th	Night	1 4 1 4 4 3 4 4 6% 8% 62%	1592
	11th to 20th	Night	1 3 1 3 3 2 1 3 5% 7% 71%	1520
	21st to end	Night	1 3 1 2 2 2 2 3 4 6% 75%	1520
July	1st to 10th	Night	1 2 2 1 1 1 3 4 84%	2540
	11th to 20th	Night	1 1 2 2 2 2 2 5% 6% 78%	2598
	21st to end	Night	1 1 1 1 2 2 2 3 4 82%	3357
August	1st to 10th	Night	1 2 1 2 1 2 1 2 4 5% 80%	3166
	11th to 20th	Night	1 1 1 1 1 1 1 3 4 84%	3126
	21st to end	Night	1 1 1 2 2 1 1 1 3 4 83%	3498
September	1st to 10th	Night	2 3 1 3 2 2 2 2 3 5% 75%	1900
	11th to 20th	Night	2 2 1 2 2 2 2 1 3 5% 78%	2004
	21st to end	Night	1 1 1 2 2 2 2 2 4 4 80%	2090
October	1st to 10th	Night	2 1 1 2 2 2 2 2 2 2 82%	3490
	11th to 20th	Night	2 2 2 7% 3 2 3 2 4 6% 66%	3767
	21st to end	Night	2 2 1 3 2 2 2 2 3 4 76%	4121
November	1st to 10th	Night	3 3 1 3 2 3 3 3 5% 5% 70%	2528
	11th to 20th	Night	4 2 1 4 2 2 3 2 4 5% 71%	2600
	21st to end	Night	5% 3 1 4 3 3 4 3 5% 6% 62%	2528
December	1st to 10th	Night	8% 4 2 4 3 4 3 3 5% 6% 59%	2470
	11th to 20th	Night	16% 7% 2 5% 3 3 3 3 5% 7% 46%	3041
	21st to end	Night	12% 8% 2 6% 5% 5% 5% 3 4 6% 45%	4862

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	19% 3 4 25% 34% 15%	2543
	11th to 20th	Day	28% 3 12% 21% 21% 15%	2860
	21st to end	Day	31% 3 5% 21% 25% 15%	3351
February	1st to 10th	Day	26% 3 3 15% 25% 28%	1900
	11th to 20th	Day	23% 3 6% 17% 28% 23%	1860
	21st to end	Day	27% 5% 6% 20% 24% 18%	1570
March	1st to 10th	Day	32% 4 7% 23% 17% 17%	3138
	11th to 20th	Day	18% 5% 9% 32% 19% 16%	3325
	21st to end	Day	28% 7% 13% 27% 17% 9%	4155
April	1st to 10th	Day	23% 5% 11% 25% 22% 14%	2280
	11th to 20th	Day	21% 3 6% 24% 29% 17%	2252
	21st to end	Day	18% 4 8% 26% 31% 13%	2280
May	1st to 10th	Day	16% 3 7% 20% 32% 21%	3820
	11th to 20th	Day	23% 4 8% 28% 29% 9%	4074
	21st to end	Day	20% 5% 8% 34% 28% 5%	4477
June	1st to 10th	Day	22% 3 10% 24% 29% 12%	2581
	11th to 20th	Day	16% 2 6% 16% 34% 25%	2660
	21st to end	Day	13% 2 3 12% 34% 36%	2660
July	1st to 10th	Day	8% 2 1 7% 16% 66%	4351
	11th to 20th	Day	11% 1 4 11% 27% 46%	4283
	21st to end	Day	8% 1 3 19% 31% 38%	4078
August	1st to 10th	Day	9% 1 1 10% 44% 35%	3770
	11th to 20th	Day	5% 1 1 10% 34% 48%	3760
	21st to end	Day	6% 1 1 10% 31% 50%	4179
September	1st to 10th	Day	10% 3 2 11% 32% 42%	2280
	11th to 20th	Day	12% 2 2 15% 32% 36%	2176
	21st to end	Day	12% 2 2 17% 35% 33%	2090
October	1st to 10th	Day	9% 2 3 12% 17% 56%	3490
	11th to 20th	Day	16% 1 5% 14% 35% 29%	3167
	21st to end	Day	17% 2 4 8% 33% 36%	3448
November	1st to 10th	Day	17% 2 3 18% 25% 35%	1769
	11th to 20th	Day	18% 2 5% 14% 22% 39%	1800
	21st to end	Day	22% 3 6% 13% 23% 33%	1746
December	1st to 10th	Day	27% 3 6% 16% 22% 26%	1710
	11th to 20th	Day	40% 4 6% 14% 22% 15%	2164
	21st to end	Day	37% 5% 6% 23% 17% 12%	2794
January	1st to 10th	Night	23% 3 5% 14% 35% 19%	4397
	11th to 20th	Night	30% 4 8% 24% 17% 17%	4110
	21st to end	Night	31% 5% 5% 16% 25% 18%	4305
February	1st to 10th	Night	25% 3 5% 14% 25% 28%	2280
	11th to 20th	Night	25% 3 4 17% 25% 26%	2219
	21st to end	Night	29% 4 5% 17% 23% 22%	1884
March	1st to 10th	Night	29% 8% 6% 21% 22% 14%	3736
	11th to 20th	Night	21% 6% 9% 29% 18% 16%	3650
	21st to end	Night	27% 4 9% 28% 23% 9%	3497
April	1st to 10th	Night	25% 4 9% 25% 22% 16%	1900
	11th to 20th	Night	20% 4 6% 24% 27% 19%	1879
	21st to end	Night	18% 4 8% 26% 31% 13%	1900
May	1st to 10th	Night	18% 6% 6% 19% 31% 21%	3158
	11th to 20th	Night	25% 7% 6% 25% 27% 9%	2835
	21st to end	Night	15% 6% 5% 36% 31% 6%	3110
June	1st to 10th	Night	20% 5% 11% 24% 27% 13%	1592
	11th to 20th	Night	13% 4 5% 21% 33% 25%	1520
	21st to end	Night	13% 3 2 13% 31% 37%	1520
July	1st to 10th	Night	6% 2 1 8% 15% 68%	2500
	11th to 20th	Night	10% 2 4 11% 22% 52%	2550
	21st to end	Night	8% 2 3 18% 27% 42%	3252
August	1st to 10th	Night	9% 2 2 11% 39% 38%	3156
	11th to 20th	Night	7% 2 1 9% 33% 48%	3156
	21st to end	Night	8% 2 1 6% 33% 49%	3498
September	1st to 10th	Night	13% 3 3 9% 28% 44%	1900
	11th to 20th	Night	12% 3 1 13% 34% 38%	2004
	21st to end	Night	10% 2 3 15% 32% 38%	2090
October	1st to 10th	Night	10% 2 1 10% 16% 61%	3490
	11th to 20th	Night	20% 2 3 12% 29% 33%	3767
	21st to end	Night	13% 2 2 8% 28% 46%	4121
November	1st to 10th	Night	16% 3 3 16% 26% 36%	2528
	11th to 20th	Night	17% 3 5% 12% 23% 40%	2600
	21st to end	Night	23% 3 4 17% 19% 33%	2528
December	1st to 10th	Night	26% 3 4 15% 21% 30%	2470
	11th to 20th	Night	39% 3 6% 14% 21% 17%	3041
	21st to end	Night	40% 5% 5% 20% 18% 13%	4862

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	18% 9% 29% 28% 15% 1	184
	11th to 20th	Day	14% 10% 34% 27% 14% 1	370
	21st to end	Day	14% 15% 34% 25% 10% 2	467
February	1st to 10th	Day	13% 11% 35% 25% 11% 4	460
	11th to 20th	Day	10% 13% 33% 31% 10% 3	455
	21st to end	Day	12% 14% 34% 30% 9% 1	382
March	1st to 10th	Day	13% 17% 33% 24% 12% 2	460
	11th to 20th	Day	13% 14% 32% 27% 12% 3	460
	21st to end	Day	12% 14% 34% 28% 9% 3	506
April	1st to 10th	Day	9% 10% 30% 31% 16% 4	460
	11th to 20th	Day	7% 13% 34% 28% 12% 5%	452
	21st to end	Day	4 10% 32% 32% 14% 9%	460
May	1st to 10th	Day	7% 9% 28% 34% 17% 4	463
	11th to 20th	Day	6% 6% 25% 33% 25% 5%	488
	21st to end	Day	5% 8% 23% 35% 22% 7%	529
June	1st to 10th	Day	6% 4 19% 30% 32% 10%	490
	11th to 20th	Day	4 3 13% 38% 30% 12%	490
	21st to end	Day	2 1 11% 32% 38% 17%	490
July	1st to 10th	Day	1 4 34% 43% 19%	486
	11th to 20th	Day	1 1 5% 28% 39% 26%	484
	21st to end	Day	1 1 4 30% 37% 27%	531
August	1st to 10th	Day	3 7% 37% 34% 19%	487
	11th to 20th	Day	3 5% 33% 41% 19%	477
	21st to end	Day	1 9% 38% 35% 17%	539
September	1st to 10th	Day	2 1 13% 38% 30% 16%	490
	11th to 20th	Day	3 2 18% 41% 26% 9%	490
	21st to end	Day	2 3 20% 37% 27% 11%	490
October	1st to 10th	Day	2 5% 22% 36% 28% 6%	490
	11th to 20th	Day	2 5% 26% 38% 21% 8%	490
	21st to end	Day	4 8% 28% 34% 20% 7%	539
November	1st to 10th	Day	6% 6% 21% 30% 26% 10%	305
	11th to 20th	Day	5% 8% 27% 38% 18% 4	300
	21st to end	Day	8% 10% 23% 36% 18% 5%	282
December	1st to 10th	Day	13% 5% 28% 31% 20% 3	270
	11th to 20th	Day	9% 10% 25% 34% 18% 4	268
	21st to end	Day	15% 12% 30% 27% 15% 2	198
January	1st to 10th	Night	11% 5% 18% 41% 20% 5%	760
	11th to 20th	Night	9% 4 23% 42% 19% 3	760
	21st to end	Night	14% 8% 21% 37% 17% 3	836
February	1st to 10th	Night	11% 6% 17% 39% 23% 4	760
	11th to 20th	Night	10% 5% 17% 41% 22% 6%	744
	21st to end	Night	14% 5% 18% 40% 19% 3	628
March	1st to 10th	Night	11% 4 17% 45% 21% 2	760
	11th to 20th	Night	7% 4 13% 41% 29% 6%	760
	21st to end	Night	9% 4 15% 43% 25% 4	836
April	1st to 10th	Night	8% 4 11% 45% 29% 4	760
	11th to 20th	Night	6% 4 13% 42% 32% 3	751
	21st to end	Night	5% 4 9% 40% 33% 8%	760
May	1st to 10th	Night	6% 3 8% 41% 37% 6%	751
	11th to 20th	Night	4 2 9% 38% 42% 6%	561
	21st to end	Night	3 2 9% 36% 43% 7%	617
June	1st to 10th	Night	2 1 5% 32% 50% 10%	452
	11th to 20th	Night	2 1 1 29% 59% 8%	380
	21st to end	Night	2 1 25% 63% 9%	380
July	1st to 10th	Night	2 10% 72% 16%	370
	11th to 20th	Night	1 10% 67% 22%	400
	21st to end	Night	2 1 9% 65% 23%	771
August	1st to 10th	Night	3 1 1 17% 62% 17%	756
	11th to 20th	Night	1 1 1 12% 64% 21%	752
	21st to end	Night	1 1 17% 58% 22%	836
September	1st to 10th	Night	3 1 1 22% 55% 17%	760
	11th to 20th	Night	2 2 3 29% 50% 14%	760
	21st to end	Night	2 1 4 33% 48% 13%	760
October	1st to 10th	Night	3 1 5% 42% 43% 6%	760
	11th to 20th	Night	5% 2 8% 38% 39% 9%	760
	21st to end	Night	5% 2 14% 38% 30% 11%	836
November	1st to 10th	Night	5% 2 12% 43% 30% 8%	780
	11th to 20th	Night	5% 2 15% 43% 28% 7%	800
	21st to end	Night	7% 4 19% 40% 24% 6%	778
December	1st to 10th	Night	10% 6% 19% 38% 22% 6%	760
	11th to 20th	Night	14% 4 17% 40% 21% 3	760
	21st to end	Night	12% 7% 17% 40% 21% 3	836

Page generated at 2024-11-22 05:02:24. Version ac07

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