Goliad State Park & Historic Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Goliad State Park & Historic Site clear sky chart from 2005-11-06 to 2025-06-10.

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% 5% 4 5% 4 6% 8% 41%	119859
	Night	15% 6% 2 5% 3 3 3 3 5% 7% 46%	118636
Transparency	Day	39% 7% 11% 21% 15% 9%	123655
	Night	37% 5% 12% 20% 16% 10%	122970
Seeing	Day	12% 6% 22% 30% 22% 8%	15402
	Night	15% 6% 23% 35% 19% 2	25394

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	19% 10% 3 7% 4 3 3 3 4 5% 39%	4077
	11th to 20th	Day	16% 6% 2 5% 3 3 3 3 4 6% 49%	4080
	21st to end	Day	28% 7% 2 5% 3 3 3 3 5% 6% 34%	4787
February	1st to 10th	Day	21% 7% 3 6% 4 4 4 3 4 5% 40%	2000
	11th to 20th	Day	20% 9% 3 5% 4 4 3 3 4 5% 40%	1949
	21st to end	Day	19% 8% 2 6% 3 3 4 2 4 5% 44%	1697
March	1st to 10th	Day	13% 6% 2 7% 4 4 4 3 5% 7% 44%	4936
	11th to 20th	Day	16% 7% 2 6% 4 4 3 2 4 5% 46%	4980
	21st to end	Day	16% 6% 2 6% 4 4 4 4 5% 6% 42%	5462
April	1st to 10th	Day	12% 8% 2 6% 5% 4 4 4 6% 6% 42%	2200
	11th to 20th	Day	16% 7% 3 8% 4 4 4 3 4 7% 39%	2176
	21st to end	Day	12% 8% 2 7% 5% 4 5% 4 5% 7% 41%	2420
May	1st to 10th	Day	18% 7% 3 7% 5% 5% 6% 4 6% 9% 30%	5862
	11th to 20th	Day	9% 5% 2 5% 4 4 5% 4 6% 8% 47%	5862
	21st to end	Day	8% 6% 2 7% 5% 5% 6% 5% 7% 10% 39%	6434
June	1st to 10th	Day	5% 4 1 5% 5% 6% 6% 5% 9% 10% 44%	2588
	11th to 20th	Day	5% 4 2 7% 6% 6% 6% 6% 7% 10% 42%	2470
	21st to end	Day	8% 6% 2 7% 6% 7% 7% 6% 8% 11% 33%	2470
July	1st to 10th	Day	8% 5% 2 6% 5% 6% 6% 5% 8% 10% 39%	4120
	11th to 20th	Day	6% 7% 3 8% 6% 7% 8% 7% 8% 12% 29%	4120
	21st to end	Day	10% 8% 3 8% 6% 5% 6% 5% 7% 10% 33%	4465
August	1st to 10th	Day	1 2 1 3 3 3 4 4 7% 10% 63%	4104
	11th to 20th	Day	2 3 1 3 4 5% 7% 7% 9% 12% 45%	3765
	21st to end	Day	5% 4 2 8% 6% 7% 6% 5% 9% 12% 35%	3869
September	1st to 10th	Day	9% 6% 3 9% 7% 6% 6% 5% 7% 8% 34%	2090
	11th to 20th	Day	10% 6% 3 7% 6% 6% 6% 6% 8% 9% 35%	2090
	21st to end	Day	7% 6% 2 5% 5% 5% 5% 5% 7% 9% 45%	2090
October	1st to 10th	Day	6% 3 2 4 4 4 5% 5% 7% 9% 50%	2090
	11th to 20th	Day	11% 6% 2 6% 4 4 5% 3 4 6% 50%	1929
	21st to end	Day	10% 3 2 5% 4 4 4 3 4 7% 54%	2090
November	1st to 10th	Day	12% 6% 2 6% 6% 5% 5% 4 5% 9% 41%	1958
	11th to 20th	Day	14% 6% 2 6% 3 4 4 3 5% 6% 48%	2000
	21st to end	Day	16% 8% 4 6% 4 4 4 4 4 6% 40%	1810
December	1st to 10th	Day	31% 11% 3 6% 4 3 2 2 4 5% 30%	2940
	11th to 20th	Day	13% 8% 3 7% 5% 5% 4 4 5% 6% 40%	3391
	21st to end	Day	13% 7% 2 6% 4 3 3 3 4 6% 50%	4488
January	1st to 10th	Night	23% 9% 2 5% 3 3 2 2 4 5% 42%	5888
	11th to 20th	Night	15% 5% 2 5% 3 3 3 2 4 7% 52%	5900
	21st to end	Night	32% 6% 2 5% 3 3 3 3 5% 6% 33%	6232
February	1st to 10th	Night	20% 9% 3 6% 4 3 3 3 4 5% 41%	2400
	11th to 20th	Night	20% 7% 2 5% 3 3 3 2 4 7% 43%	2338
	21st to end	Night	21% 9% 2 5% 3 4 3 3 5% 4 42%	1930
March	1st to 10th	Night	21% 9% 3 6% 3 3 4 3 4 5% 38%	4919
	11th to 20th	Night	20% 7% 3 5% 3 3 3 2 3 5% 46%	4980
	21st to end	Night	20% 8% 2 5% 3 2 3 3 4 5% 45%	5467
April	1st to 10th	Night	14% 8% 3 6% 4 4 5% 4 5% 8% 39%	2200
	11th to 20th	Night	18% 6% 2 6% 3 4 3 3 4 6% 42%	2173
	21st to end	Night	16% 9% 4 7% 4 4 4 3 6% 6% 37%	1973
May	1st to 10th	Night	27% 10% 3 7% 5% 4 4 4 5% 6% 26%	4053
	11th to 20th	Night	13% 7% 3 5% 3 3 3 3 5% 8% 46%	4053
	21st to end	Night	15% 9% 3 8% 5% 5% 4 4 6% 9% 32%	4443
June	1st to 10th	Night	7% 3 1 4 3 3 4 5% 6% 10% 54%	1796
	11th to 20th	Night	7% 3 1 4 3 4 5% 4 6% 9% 53%	1710
	21st to end	Night	6% 4 2 5% 4 5% 5% 5% 8% 10% 46%	1710
July	1st to 10th	Night	5% 4 2 4 4 4 4 4 7% 10% 53%	2850
	11th to 20th	Night	4 5% 2 6% 5% 5% 6% 5% 7% 11% 43%	2850
	21st to end	Night	7% 6% 2 6% 5% 5% 5% 4 7% 10% 42%	3098
August	1st to 10th	Night	1 1 1 1 2 2 2 5% 7% 78%	2836
	11th to 20th	Night	2 2 1 3 2 3 4 4 7% 14% 59%	3069
	21st to end	Night	3 2 1 4 3 3 4 3 7% 13% 57%	3787
September	1st to 10th	Night	8% 5% 2 5% 4 4 5% 4 6% 10% 47%	2090
	11th to 20th	Night	8% 5% 2 7% 4 4 4 4 7% 8% 49%	2090
	21st to end	Night	7% 3 1 6% 3 3 5% 3 6% 8% 55%	2090
October	1st to 10th	Night	4 4 1 3 2 3 3 3 6% 6% 63%	2090
	11th to 20th	Night	10% 5% 2 4 3 3 3 3 3 6% 59%	2231
	21st to end	Night	10% 4 1 3 3 2 3 2 3 5% 64%	2508
November	1st to 10th	Night	11% 5% 2 6% 4 3 3 3 5% 5% 52%	2340
	11th to 20th	Night	13% 7% 2 6% 3 3 4 3 4 5% 52%	2400
	21st to end	Night	16% 6% 2 6% 4 4 3 3 5% 7% 44%	2586
December	1st to 10th	Night	32% 12% 3 6% 3 3 2 2 2 4 30%	4250
	11th to 20th	Night	14% 9% 2 7% 4 4 4 2 4 6% 44%	4816
	21st to end	Night	13% 6% 2 5% 3 3 3 3 4 6% 52%	6490

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	49% 4 4 15% 18% 9%	4078
	11th to 20th	Day	37% 4 5% 22% 21% 11%	4080
	21st to end	Day	51% 3 5% 12% 18% 12%	4787
February	1st to 10th	Day	47% 4 6% 10% 19% 14%	2000
	11th to 20th	Day	47% 4 8% 15% 15% 11%	1959
	21st to end	Day	43% 6% 7% 18% 15% 12%	1697
March	1st to 10th	Day	40% 6% 8% 18% 12% 16%	4936
	11th to 20th	Day	41% 5% 5% 10% 16% 23%	4980
	21st to end	Day	41% 6% 8% 19% 18% 9%	5464
April	1st to 10th	Day	41% 7% 9% 15% 16% 12%	2200
	11th to 20th	Day	45% 6% 7% 16% 15% 11%	2176
	21st to end	Day	42% 6% 8% 19% 15% 9%	2420
May	1st to 10th	Day	48% 7% 12% 19% 10% 3	5900
	11th to 20th	Day	33% 7% 12% 23% 17% 8%	5866
	21st to end	Day	36% 8% 11% 34% 10% 1	6447
June	1st to 10th	Day	29% 9% 16% 28% 17% 1	2588
	11th to 20th	Day	34% 8% 12% 26% 17% 4	2470
	21st to end	Day	41% 10% 14% 25% 8% 1	2470
July	1st to 10th	Day	35% 9% 21% 29% 5%	4056
	11th to 20th	Day	43% 11% 17% 20% 9%	4051
	21st to end	Day	42% 10% 20% 25% 3	4325
August	1st to 10th	Day	16% 7% 14% 48% 15%	4090
	11th to 20th	Day	25% 11% 26% 31% 6% 1	3802
	21st to end	Day	37% 11% 18% 23% 10% 1	3868
September	1st to 10th	Day	45% 11% 11% 15% 14% 4	2090
	11th to 20th	Day	41% 9% 15% 19% 14% 3	2090
	21st to end	Day	34% 9% 12% 18% 17% 11%	2090
October	1st to 10th	Day	21% 5% 7% 13% 19% 35%	3480
	11th to 20th	Day	27% 5% 8% 19% 23% 18%	3182
	21st to end	Day	28% 5% 7% 19% 29% 14%	3428
November	1st to 10th	Day	39% 7% 9% 17% 19% 9%	1958
	11th to 20th	Day	38% 5% 9% 16% 19% 14%	2000
	21st to end	Day	45% 6% 7% 16% 15% 12%	1810
December	1st to 10th	Day	58% 3 5% 13% 16% 5%	2940
	11th to 20th	Day	43% 6% 6% 17% 16% 12%	3389
	21st to end	Day	36% 4 5% 21% 19% 15%	4488
January	1st to 10th	Night	46% 4 5% 15% 16% 15%	5888
	11th to 20th	Night	34% 3 5% 21% 22% 15%	5900
	21st to end	Night	53% 3 5% 11% 17% 12%	6232
February	1st to 10th	Night	46% 4 9% 10% 16% 16%	2400
	11th to 20th	Night	43% 5% 8% 15% 17% 12%	2338
	21st to end	Night	45% 5% 7% 16% 16% 11%	1930
March	1st to 10th	Night	48% 4 7% 16% 13% 12%	4919
	11th to 20th	Night	43% 4 6% 11% 15% 21%	4980
	21st to end	Night	42% 4 10% 17% 18% 9%	5467
April	1st to 10th	Night	43% 6% 11% 17% 13% 10%	2200
	11th to 20th	Night	43% 5% 9% 16% 13% 15%	2173
	21st to end	Night	47% 5% 11% 16% 13% 8%	1973
May	1st to 10th	Night	57% 6% 9% 14% 9% 4	4080
	11th to 20th	Night	36% 6% 12% 23% 17% 7%	4054
	21st to end	Night	47% 9% 15% 24% 5%	4452
June	1st to 10th	Night	24% 7% 20% 32% 16% 1	1796
	11th to 20th	Night	28% 7% 12% 32% 19% 3	1710
	21st to end	Night	30% 10% 20% 30% 8% 1	1710
July	1st to 10th	Night	26% 9% 27% 35% 3	2805
	11th to 20th	Night	32% 11% 25% 24% 8%	2796
	21st to end	Night	35% 11% 25% 25% 4	2999
August	1st to 10th	Night	7% 5% 18% 56% 14%	2826
	11th to 20th	Night	16% 7% 41% 33% 3	3098
	21st to end	Night	19% 12% 28% 31% 9% 1	3787
September	1st to 10th	Night	31% 10% 22% 21% 12% 4	2090
	11th to 20th	Night	31% 10% 16% 24% 15% 4	2090
	21st to end	Night	26% 7% 15% 24% 18% 9%	2090
October	1st to 10th	Night	15% 4 9% 18% 20% 33%	3480
	11th to 20th	Night	20% 4 9% 21% 28% 18%	3704
	21st to end	Night	20% 3 6% 26% 30% 15%	4120
November	1st to 10th	Night	33% 6% 11% 19% 21% 10%	2340
	11th to 20th	Night	35% 5% 11% 16% 18% 15%	2400
	21st to end	Night	40% 4 10% 18% 17% 11%	2586
December	1st to 10th	Night	60% 3 6% 12% 12% 6%	4250
	11th to 20th	Night	42% 4 9% 14% 16% 15%	4817
	21st to end	Night	34% 5% 5% 18% 24% 14%	6490

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	22% 9% 32% 28% 7% 2	300
	11th to 20th	Day	23% 9% 35% 25% 7% 1	300
	21st to end	Day	21% 14% 33% 22% 11%	330
February	1st to 10th	Day	21% 13% 28% 26% 11%	300
	11th to 20th	Day	26% 14% 32% 19% 8% 1	300
	21st to end	Day	24% 13% 38% 19% 6%	249
March	1st to 10th	Day	19% 16% 37% 22% 6%	300
	11th to 20th	Day	18% 15% 41% 21% 5%	300
	21st to end	Day	17% 15% 38% 23% 7% 1	330
April	1st to 10th	Day	16% 17% 37% 23% 5% 1	300
	11th to 20th	Day	17% 16% 35% 21% 10% 1	294
	21st to end	Day	14% 12% 40% 26% 8%	520
May	1st to 10th	Day	15% 13% 42% 25% 6%	703
	11th to 20th	Day	12% 8% 35% 31% 12% 2	725
	21st to end	Day	9% 6% 34% 33% 17% 1	789
June	1st to 10th	Day	5% 1 19% 38% 30% 7%	726
	11th to 20th	Day	5% 1 16% 45% 26% 6%	680
	21st to end	Day	9% 3 12% 36% 29% 12%	680
July	1st to 10th	Day	9% 3 8% 34% 32% 15%	671
	11th to 20th	Day	5% 1 6% 32% 43% 14%	668
	21st to end	Day	6% 2 4 36% 37% 16%	739
August	1st to 10th	Day	2 1 4 33% 40% 21%	676
	11th to 20th	Day	3 1 5% 38% 34% 20%	504
	21st to end	Day	7% 1 5% 24% 31% 32%	358
September	1st to 10th	Day	11% 6% 22% 39% 22%	300
	11th to 20th	Day	8% 1 5% 21% 41% 25%	300
	21st to end	Day	9% 1 5% 27% 40% 19%	300
October	1st to 10th	Day	5% 2 12% 31% 37% 13%	300
	11th to 20th	Day	11% 2 13% 35% 26% 13%	300
	21st to end	Day	13% 8% 21% 32% 18% 8%	330
November	1st to 10th	Day	16% 6% 18% 32% 24% 5%	300
	11th to 20th	Day	18% 5% 24% 27% 21% 5%	300
	21st to end	Day	21% 12% 31% 21% 12% 4	300
December	1st to 10th	Day	21% 7% 23% 33% 12% 4	300
	11th to 20th	Day	23% 11% 29% 24% 12% 2	300
	21st to end	Day	21% 8% 32% 24% 13% 2	330
January	1st to 10th	Night	24% 8% 29% 29% 10%	1000
	11th to 20th	Night	22% 9% 27% 34% 8%	1000
	21st to end	Night	24% 8% 29% 33% 6%	985
February	1st to 10th	Night	25% 11% 28% 30% 6%	800
	11th to 20th	Night	24% 11% 31% 30% 4	784
	21st to end	Night	28% 8% 37% 23% 4	610
March	1st to 10th	Night	26% 9% 31% 30% 5%	600
	11th to 20th	Night	22% 10% 31% 33% 4	600
	21st to end	Night	19% 10% 35% 31% 5%	660
April	1st to 10th	Night	17% 8% 42% 28% 5%	600
	11th to 20th	Night	21% 10% 32% 31% 6%	593
	21st to end	Night	18% 10% 39% 27% 6%	600
May	1st to 10th	Night	17% 8% 41% 29% 5%	600
	11th to 20th	Night	13% 4 32% 40% 10% 1	591
	21st to end	Night	10% 4 31% 40% 14%	650
June	1st to 10th	Night	6% 2 17% 49% 25% 1	599
	11th to 20th	Night	7% 1 17% 52% 22% 1	570
	21st to end	Night	8% 1 12% 41% 35% 3	570
July	1st to 10th	Night	8% 1 7% 44% 35% 5%	555
	11th to 20th	Night	2 1 6% 39% 47% 5%	552
	21st to end	Night	4 1 5% 43% 43% 5%	624
August	1st to 10th	Night	1 3 43% 47% 5%	567
	11th to 20th	Night	4 4 40% 47% 5%	564
	21st to end	Night	5% 1 4 29% 53% 8%	627
September	1st to 10th	Night	10% 1 4 31% 47% 7%	570
	11th to 20th	Night	9% 2 4 32% 47% 5%	570
	21st to end	Night	9% 1 9% 31% 47% 5%	570
October	1st to 10th	Night	6% 1 7% 40% 42% 4	570
	11th to 20th	Night	11% 3 19% 45% 21% 2	711
	21st to end	Night	10% 5% 23% 38% 22% 1	836
November	1st to 10th	Night	12% 5% 21% 41% 20% 1	780
	11th to 20th	Night	17% 5% 22% 38% 17% 2	800
	21st to end	Night	18% 7% 28% 30% 16% 1	986
December	1st to 10th	Night	23% 7% 24% 32% 14% 1	1000
	11th to 20th	Night	22% 10% 27% 31% 10% 1	1000
	21st to end	Night	21% 8% 27% 34% 9% 1	1100

Page generated at 2025-06-07 09:28:16. Version ac07

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