Mustang Island State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mustang Island State Park clear sky chart from 2005-11-06 to 2024-03-08.

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% 5% 2 4 4 3 4 5% 6% 9% 46%	79042
	Night	13% 5% 2 4 4 3 4 5% 6% 8% 46%	80575
Transparency	Day	34% 9% 17% 22% 13% 5%	78767
	Night	35% 7% 15% 21% 15% 7%	80370
Seeing	Day	11% 3 11% 25% 35% 15%	13579
	Night	14% 4 13% 30% 32% 8%	23697

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	18% 7% 3 6% 4 3 4 5% 6% 7% 38%	2847
	11th to 20th	Day	16% 8% 2 5% 4 3 3 3 5% 7% 44%	2850
	21st to end	Day	22% 6% 3 6% 4 3 5% 5% 5% 5% 36%	3373
February	1st to 10th	Day	21% 8% 3 5% 4 2 4 4 5% 5% 38%	1900
	11th to 20th	Day	20% 6% 3 5% 4 2 3 3 5% 7% 43%	1849
	21st to end	Day	18% 7% 3 5% 5% 2 4 4 4 6% 43%	1646
March	1st to 10th	Day	19% 7% 2 6% 5% 3 4 4 4 7% 40%	2057
	11th to 20th	Day	17% 7% 4 5% 5% 3 4 4 5% 7% 39%	1980
	21st to end	Day	12% 6% 3 5% 4 3 4 4 4 7% 48%	2178
April	1st to 10th	Day	14% 6% 3 4 4 4 5% 5% 6% 8% 41%	1980
	11th to 20th	Day	15% 6% 3 5% 5% 3 4 4 5% 7% 43%	1956
	21st to end	Day	12% 5% 3 4 4 3 4 4 6% 7% 48%	2137
May	1st to 10th	Day	9% 5% 2 5% 6% 3 5% 5% 6% 10% 45%	2306
	11th to 20th	Day	9% 4 2 5% 4 4 5% 6% 6% 9% 46%	2302
	21st to end	Day	6% 4 2 3 4 3 6% 5% 7% 11% 49%	2531
June	1st to 10th	Day	4 1 2 3 4 2 4 5% 7% 12% 55%	2340
	11th to 20th	Day	3 2 1 3 4 3 5% 5% 7% 13% 55%	2340
	21st to end	Day	6% 4 2 4 4 4 5% 6% 8% 14% 43%	2340
July	1st to 10th	Day	8% 4 2 5% 5% 3 5% 5% 7% 12% 44%	2340
	11th to 20th	Day	4 2 2 3 4 3 5% 6% 6% 13% 53%	2340
	21st to end	Day	4 2 2 3 3 3 4 5% 6% 11% 56%	2546
August	1st to 10th	Day	1 1 1 2 3 2 3 5% 7% 10% 64%	2328
	11th to 20th	Day	4 2 1 4 2 2 3 5% 7% 15% 54%	2124
	21st to end	Day	7% 3 1 4 5% 3 6% 7% 7% 13% 44%	2178
September	1st to 10th	Day	8% 5% 2 6% 5% 4 6% 6% 8% 10% 39%	1980
	11th to 20th	Day	10% 5% 3 5% 5% 4 7% 5% 6% 8% 41%	1980
	21st to end	Day	10% 4 2 4 4 3 4 5% 7% 11% 46%	1980
October	1st to 10th	Day	5% 4 2 4 5% 3 5% 4 5% 9% 53%	1980
	11th to 20th	Day	10% 4 2 4 4 2 4 5% 4 7% 53%	1825
	21st to end	Day	10% 4 2 4 4 3 4 3 5% 6% 56%	1980
November	1st to 10th	Day	11% 5% 2 4 4 2 5% 5% 6% 9% 48%	1858
	11th to 20th	Day	16% 6% 3 4 5% 2 4 3 4 6% 46%	1900
	21st to end	Day	17% 6% 2 5% 4 3 4 4 4 6% 44%	1785
December	1st to 10th	Day	21% 7% 2 5% 4 2 4 4 5% 7% 39%	1710
	11th to 20th	Day	16% 7% 3 6% 5% 3 4 4 5% 6% 40%	2161
	21st to end	Day	18% 7% 3 5% 4 2 4 4 5% 7% 41%	3135
January	1st to 10th	Night	21% 7% 2 5% 4 3 4 4 4 6% 40%	4108
	11th to 20th	Night	16% 6% 3 4 3 2 3 4 5% 6% 48%	4120
	21st to end	Night	23% 7% 3 6% 5% 3 4 4 6% 6% 34%	4309
February	1st to 10th	Night	19% 7% 3 5% 4 3 4 4 4 6% 41%	2280
	11th to 20th	Night	19% 6% 2 4 4 2 4 5% 4 6% 44%	2218
	21st to end	Night	18% 8% 3 4 4 3 4 4 3 7% 43%	1806
March	1st to 10th	Night	16% 8% 2 5% 4 2 3 4 5% 8% 43%	2063
	11th to 20th	Night	14% 8% 4 6% 5% 3 4 3 5% 7% 41%	1980
	21st to end	Night	12% 7% 3 4 3 2 3 3 5% 7% 51%	2178
April	1st to 10th	Night	14% 7% 3 5% 5% 3 4 4 6% 9% 39%	1980
	11th to 20th	Night	16% 7% 3 5% 5% 3 4 3 5% 8% 43%	1953
	21st to end	Night	13% 7% 3 6% 5% 3 4 6% 5% 9% 41%	1822
May	1st to 10th	Night	11% 6% 2 4 5% 3 4 5% 7% 9% 43%	1648
	11th to 20th	Night	10% 5% 2 5% 5% 4 4 6% 7% 9% 43%	1593
	21st to end	Night	5% 4 2 5% 5% 4 5% 5% 8% 13% 44%	1745
June	1st to 10th	Night	5% 2 1 3 4 2 5% 5% 9% 10% 55%	1620
	11th to 20th	Night	3 3 1 4 4 3 5% 5% 8% 15% 48%	1620
	21st to end	Night	6% 3 2 4 5% 3 5% 7% 7% 12% 46%	1620
July	1st to 10th	Night	7% 5% 2 4 5% 4 5% 7% 8% 12% 43%	1620
	11th to 20th	Night	3 2 1 3 3 3 5% 5% 7% 12% 56%	1620
	21st to end	Night	4 2 1 2 3 3 4 4 6% 11% 59%	1772
August	1st to 10th	Night	1 1 1 1 2 2 3 3 5% 12% 69%	1611
	11th to 20th	Night	3 2 2 3 3 2 3 5% 6% 12% 58%	1772
	21st to end	Night	4 3 2 4 4 3 4 6% 7% 11% 51%	2178
September	1st to 10th	Night	6% 5% 3 4 5% 3 5% 7% 7% 11% 44%	1980
	11th to 20th	Night	10% 6% 2 5% 6% 3 4 6% 5% 9% 43%	1980
	21st to end	Night	8% 3 2 4 5% 3 4 5% 6% 9% 50%	1980
October	1st to 10th	Night	4 3 2 4 4 2 5% 5% 6% 9% 56%	1980
	11th to 20th	Night	10% 4 1 4 3 2 3 3 5% 7% 58%	2114
	21st to end	Night	10% 3 1 3 3 2 3 3 5% 6% 60%	2376
November	1st to 10th	Night	12% 4 2 3 3 2 3 4 5% 8% 54%	2220
	11th to 20th	Night	16% 5% 3 5% 4 2 3 3 3 5% 50%	2280
	21st to end	Night	17% 7% 2 5% 5% 3 4 4 5% 6% 43%	2391
December	1st to 10th	Night	19% 6% 2 4 4 2 3 4 4 7% 45%	2470
	11th to 20th	Night	18% 7% 3 5% 5% 3 4 4 5% 7% 39%	3036
	21st to end	Night	15% 7% 3 5% 5% 3 4 5% 6% 6% 41%	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	42% 9% 10% 16% 14% 9%	2848
	11th to 20th	Day	38% 10% 10% 16% 15% 10%	2850
	21st to end	Day	49% 5% 8% 14% 17% 7%	3373
February	1st to 10th	Day	47% 7% 8% 13% 16% 9%	1900
	11th to 20th	Day	43% 5% 11% 18% 16% 7%	1859
	21st to end	Day	42% 6% 11% 20% 13% 7%	1646
March	1st to 10th	Day	44% 7% 14% 17% 12% 5%	2057
	11th to 20th	Day	45% 7% 12% 13% 15% 8%	1980
	21st to end	Day	35% 8% 14% 19% 16% 8%	2178
April	1st to 10th	Day	39% 7% 17% 18% 13% 5%	1980
	11th to 20th	Day	40% 7% 13% 18% 14% 7%	1956
	21st to end	Day	34% 8% 14% 23% 13% 8%	2137
May	1st to 10th	Day	34% 9% 16% 22% 13% 6%	2306
	11th to 20th	Day	33% 8% 16% 26% 15% 2	2306
	21st to end	Day	25% 10% 19% 30% 15% 1	2531
June	1st to 10th	Day	20% 9% 20% 35% 16%	2340
	11th to 20th	Day	20% 9% 20% 36% 14% 1	2340
	21st to end	Day	27% 13% 27% 26% 6% 1	2340
July	1st to 10th	Day	32% 11% 27% 25% 5%	2276
	11th to 20th	Day	22% 11% 31% 29% 7%	2271
	21st to end	Day	20% 11% 34% 30% 4	2405
August	1st to 10th	Day	15% 10% 31% 36% 7%	2314
	11th to 20th	Day	20% 10% 34% 32% 4	2124
	21st to end	Day	28% 13% 27% 25% 5% 1	2178
September	1st to 10th	Day	37% 14% 17% 20% 10% 2	1980
	11th to 20th	Day	38% 11% 17% 20% 12% 2	1980
	21st to end	Day	32% 11% 14% 24% 14% 4	1980
October	1st to 10th	Day	27% 8% 14% 24% 22% 4	1980
	11th to 20th	Day	31% 7% 13% 22% 18% 9%	1825
	21st to end	Day	28% 6% 10% 22% 24% 11%	1980
November	1st to 10th	Day	32% 8% 15% 22% 18% 5%	1858
	11th to 20th	Day	41% 6% 11% 17% 17% 8%	1900
	21st to end	Day	43% 7% 11% 19% 13% 7%	1785
December	1st to 10th	Day	46% 5% 12% 18% 14% 4	1710
	11th to 20th	Day	42% 8% 10% 12% 17% 11%	2159
	21st to end	Day	42% 7% 9% 20% 16% 6%	3135
January	1st to 10th	Night	44% 7% 8% 12% 14% 15%	4108
	11th to 20th	Night	36% 6% 10% 18% 20% 12%	4120
	21st to end	Night	51% 5% 7% 12% 16% 9%	4309
February	1st to 10th	Night	44% 5% 10% 13% 15% 13%	2280
	11th to 20th	Night	41% 6% 11% 14% 19% 8%	2218
	21st to end	Night	43% 6% 7% 19% 18% 8%	1806
March	1st to 10th	Night	38% 7% 15% 18% 15% 6%	2063
	11th to 20th	Night	43% 7% 12% 13% 15% 10%	1980
	21st to end	Night	35% 6% 13% 19% 18% 10%	2178
April	1st to 10th	Night	42% 6% 13% 18% 15% 6%	1980
	11th to 20th	Night	41% 6% 11% 17% 16% 9%	1953
	21st to end	Night	39% 8% 12% 18% 15% 8%	1822
May	1st to 10th	Night	37% 7% 14% 21% 12% 9%	1648
	11th to 20th	Night	34% 8% 15% 25% 14% 3	1594
	21st to end	Night	28% 9% 21% 27% 14% 1	1746
June	1st to 10th	Night	21% 7% 19% 35% 17% 1	1620
	11th to 20th	Night	25% 8% 15% 34% 16% 1	1620
	21st to end	Night	29% 9% 25% 29% 7% 1	1620
July	1st to 10th	Night	32% 10% 25% 27% 5%	1575
	11th to 20th	Night	19% 12% 32% 29% 8%	1566
	21st to end	Night	18% 9% 33% 35% 6%	1673
August	1st to 10th	Night	11% 7% 32% 42% 8%	1601
	11th to 20th	Night	19% 11% 29% 37% 4	1772
	21st to end	Night	25% 11% 28% 27% 8% 1	2178
September	1st to 10th	Night	31% 13% 24% 19% 10% 3	1980
	11th to 20th	Night	37% 9% 17% 24% 12% 2	1980
	21st to end	Night	31% 9% 15% 24% 18% 4	1980
October	1st to 10th	Night	25% 9% 14% 26% 19% 8%	1980
	11th to 20th	Night	27% 6% 13% 26% 18% 11%	2114
	21st to end	Night	27% 5% 8% 22% 25% 13%	2376
November	1st to 10th	Night	29% 8% 13% 23% 21% 6%	2220
	11th to 20th	Night	39% 5% 11% 19% 18% 8%	2280
	21st to end	Night	42% 6% 10% 21% 14% 8%	2391
December	1st to 10th	Night	42% 5% 11% 22% 14% 6%	2470
	11th to 20th	Night	42% 8% 10% 14% 14% 12%	3037
	21st to end	Night	42% 8% 10% 13% 18% 9%	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	20% 7% 26% 30% 18% 1	270
	11th to 20th	Day	19% 6% 21% 34% 17% 3	270
	21st to end	Day	21% 8% 23% 34% 13% 1	297
February	1st to 10th	Day	23% 4 20% 36% 14% 2	270
	11th to 20th	Day	24% 7% 18% 31% 19% 1	270
	21st to end	Day	21% 4 25% 42% 7% 1	225
March	1st to 10th	Day	19% 7% 23% 36% 15%	261
	11th to 20th	Day	24% 6% 18% 38% 14%	240
	21st to end	Day	13% 6% 23% 44% 13%	264
April	1st to 10th	Day	16% 6% 23% 39% 17%	240
	11th to 20th	Day	17% 4 24% 35% 17% 3	234
	21st to end	Day	13% 5% 24% 37% 20% 2	397
May	1st to 10th	Day	9% 4 20% 47% 18% 1	569
	11th to 20th	Day	10% 3 12% 45% 27% 3	625
	21st to end	Day	5% 2 11% 38% 41% 3	679
June	1st to 10th	Day	5% 1 5% 23% 55% 11%	630
	11th to 20th	Day	4 1 4 25% 54% 11%	630
	21st to end	Day	7% 1 3 17% 50% 22%	630
July	1st to 10th	Day	5% 1 3 16% 46% 29%	621
	11th to 20th	Day	3 1 6% 53% 36%	618
	21st to end	Day	4 2 5% 55% 34%	684
August	1st to 10th	Day	1 1 7% 54% 37%	626
	11th to 20th	Day	3 1 1 7% 44% 44%	438
	21st to end	Day	7% 1 2 7% 30% 53%	297
September	1st to 10th	Day	9% 1 1 10% 43% 35%	270
	11th to 20th	Day	10% 3 10% 37% 40%	270
	21st to end	Day	8% 1 4 11% 45% 31%	270
October	1st to 10th	Day	8% 1 2 16% 54% 19%	270
	11th to 20th	Day	12% 2 6% 19% 46% 15%	270
	21st to end	Day	13% 4 17% 27% 34% 5%	297
November	1st to 10th	Day	14% 4 7% 22% 46% 7%	270
	11th to 20th	Day	25% 4 9% 26% 29% 7%	270
	21st to end	Day	27% 4 19% 30% 17% 4	270
December	1st to 10th	Day	24% 3 13% 30% 24% 6%	270
	11th to 20th	Day	20% 9% 18% 33% 19% 1	270
	21st to end	Day	19% 4 21% 37% 16% 3	297
January	1st to 10th	Night	23% 6% 19% 35% 15% 2	950
	11th to 20th	Night	20% 6% 21% 37% 16% 1	950
	21st to end	Night	22% 5% 25% 33% 15% 1	913
February	1st to 10th	Night	22% 7% 21% 36% 14% 1	760
	11th to 20th	Night	22% 7% 20% 36% 14% 1	744
	21st to end	Night	23% 6% 19% 40% 11%	550
March	1st to 10th	Night	18% 5% 21% 38% 18% 1	563
	11th to 20th	Night	17% 6% 19% 41% 16% 1	540
	21st to end	Night	13% 5% 18% 47% 15% 1	594
April	1st to 10th	Night	16% 4 20% 44% 16%	540
	11th to 20th	Night	18% 5% 20% 40% 18%	533
	21st to end	Night	14% 5% 21% 42% 17% 1	540
May	1st to 10th	Night	12% 4 18% 46% 20%	540
	11th to 20th	Night	10% 2 13% 49% 24% 2	531
	21st to end	Night	6% 2 10% 40% 41% 2	584
June	1st to 10th	Night	4 1 2 30% 57% 6%	540
	11th to 20th	Night	4 1 3 33% 56% 4	540
	21st to end	Night	6% 1 6% 19% 52% 16%	540
July	1st to 10th	Night	5% 1 4 20% 51% 19%	525
	11th to 20th	Night	3 1 2 9% 58% 27%	522
	21st to end	Night	4 1 1 10% 61% 23%	591
August	1st to 10th	Night	1 8% 61% 29%	537
	11th to 20th	Night	2 1 1 7% 60% 29%	534
	21st to end	Night	5% 1 1 11% 47% 35%	594
September	1st to 10th	Night	7% 1 1 11% 56% 24%	540
	11th to 20th	Night	10% 1 4 13% 49% 23%	540
	21st to end	Night	9% 1 4 15% 54% 17%	540
October	1st to 10th	Night	5% 1 6% 18% 54% 16%	540
	11th to 20th	Night	10% 2 8% 28% 45% 7%	674
	21st to end	Night	11% 3 11% 35% 33% 6%	792
November	1st to 10th	Night	11% 2 10% 27% 44% 6%	740
	11th to 20th	Night	19% 3 14% 28% 33% 4	760
	21st to end	Night	18% 4 18% 32% 24% 3	871
December	1st to 10th	Night	20% 5% 18% 28% 24% 5%	950
	11th to 20th	Night	20% 6% 20% 34% 19% 2	950
	21st to end	Night	21% 7% 22% 32% 17% 2	1045

Page generated at 2024-03-05 06:24:00. Version ac07

Copyright © 2024 Attilla Danko.