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 2026-10-14.

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	11% 6% 2 6% 4 4 5% 4 6% 8% 42%	148956
	Night	14% 6% 2 5% 3 3 4 3 5% 7% 47%	143207
Transparency	Day	37% 7% 12% 22% 14% 7%	152710
	Night	37% 5% 13% 21% 15% 9%	147520
Seeing	Day	12% 6% 22% 30% 22% 8%	17238
	Night	15% 6% 22% 35% 20% 2	27069

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	17% 10% 3 7% 3 3 3 2 3 5% 43%	5289
	11th to 20th	Day	15% 7% 3 6% 3 3 3 2 4 5% 51%	5310
	21st to end	Day	25% 8% 2 6% 4 3 3 3 5% 6% 35%	6206
February	1st to 10th	Day	20% 7% 3 6% 4 4 4 3 4 5% 42%	2100
	11th to 20th	Day	19% 9% 3 6% 4 4 3 3 4 5% 40%	2049
	21st to end	Day	18% 7% 2 5% 3 3 4 2 4 5% 46%	1779
March	1st to 10th	Day	13% 7% 3 7% 4 4 4 3 5% 7% 43%	5046
	11th to 20th	Day	15% 7% 2 6% 4 4 3 2 4 5% 47%	5090
	21st to end	Day	16% 6% 2 6% 4 4 4 4 5% 6% 43%	5583
April	1st to 10th	Day	12% 8% 2 7% 5% 4 4 4 6% 6% 41%	2310
	11th to 20th	Day	16% 7% 3 8% 5% 5% 4 3 4 6% 38%	2286
	21st to end	Day	12% 8% 2 7% 5% 5% 5% 4 5% 7% 40%	2541
May	1st to 10th	Day	19% 7% 3 7% 5% 5% 5% 4 6% 8% 31%	7617
	11th to 20th	Day	9% 5% 2 6% 4 4 5% 4 6% 8% 44%	7627
	21st to end	Day	9% 7% 3 8% 5% 5% 6% 5% 7% 10% 35%	8392
June	1st to 10th	Day	5% 5% 2 5% 5% 6% 6% 5% 8% 9% 43%	2730
	11th to 20th	Day	5% 4 2 6% 6% 6% 6% 6% 7% 10% 41%	2730
	21st to end	Day	7% 5% 2 7% 6% 6% 7% 6% 8% 11% 35%	2730
July	1st to 10th	Day	7% 5% 2 6% 5% 6% 6% 5% 8% 11% 39%	7680
	11th to 20th	Day	7% 7% 3 8% 6% 6% 6% 5% 8% 12% 33%	7680
	21st to end	Day	6% 5% 2 6% 4 4 5% 5% 7% 10% 45%	8337
August	1st to 10th	Day	1 2 1 3 3 3 4 4 7% 11% 60%	6014
	11th to 20th	Day	2 2 1 3 4 4 6% 6% 8% 12% 51%	5551
	21st to end	Day	4 3 2 7% 5% 6% 6% 6% 8% 12% 43%	5621
September	1st to 10th	Day	8% 6% 3 9% 7% 6% 6% 5% 7% 9% 35%	2310
	11th to 20th	Day	9% 5% 2 7% 6% 5% 6% 5% 8% 9% 37%	2310
	21st to end	Day	6% 5% 2 5% 5% 5% 6% 5% 7% 9% 45%	2310
October	1st to 10th	Day	6% 3 2 4 4 4 5% 5% 7% 9% 51%	2310
	11th to 20th	Day	10% 5% 2 5% 4 4 5% 3 4 6% 51%	2062
	21st to end	Day	9% 3 2 5% 4 3 4 4 4 7% 55%	2200
November	1st to 10th	Day	11% 6% 2 6% 5% 4 5% 4 5% 9% 44%	2058
	11th to 20th	Day	13% 6% 2 6% 3 4 3 3 5% 6% 49%	2100
	21st to end	Day	16% 8% 4 7% 4 4 4 4 4 6% 39%	1900
December	1st to 10th	Day	31% 11% 3 5% 3 3 2 2 4 5% 31%	3030
	11th to 20th	Day	13% 8% 3 7% 5% 5% 4 4 5% 6% 40%	3481
	21st to end	Day	13% 7% 2 6% 4 3 3 3 4 6% 49%	4587
January	1st to 10th	Night	20% 8% 2 5% 3 3 3 2 3 4 46%	7634
	11th to 20th	Night	13% 6% 2 5% 3 3 3 2 3 6% 53%	7680
	21st to end	Night	30% 7% 3 5% 3 3 3 3 4 6% 34%	8063
February	1st to 10th	Night	19% 9% 3 6% 4 3 3 3 4 5% 42%	2520
	11th to 20th	Night	20% 7% 2 5% 3 3 3 2 4 7% 43%	2458
	21st to end	Night	20% 9% 2 5% 3 4 3 3 4 4 43%	2024
March	1st to 10th	Night	22% 9% 2 6% 3 3 4 3 4 5% 38%	5029
	11th to 20th	Night	19% 7% 3 5% 3 3 2 2 3 5% 47%	5090
	21st to end	Night	20% 8% 2 5% 3 2 3 3 4 5% 45%	5588
April	1st to 10th	Night	15% 8% 2 6% 4 4 5% 4 5% 7% 39%	2310
	11th to 20th	Night	19% 7% 2 6% 3 4 3 3 4 6% 41%	2283
	21st to end	Night	17% 9% 3 7% 4 4 4 3 6% 6% 36%	2072
May	1st to 10th	Night	28% 11% 3 7% 4 4 4 3 4 6% 25%	5266
	11th to 20th	Night	15% 8% 3 5% 4 3 4 3 6% 8% 42%	5265
	21st to end	Night	14% 9% 4 9% 5% 5% 5% 4 6% 9% 31%	5793
June	1st to 10th	Night	7% 4 2 4 4 3 4 4 6% 10% 52%	1890
	11th to 20th	Night	7% 3 1 5% 3 4 5% 4 7% 9% 51%	1890
	21st to end	Night	7% 4 2 5% 4 5% 5% 5% 8% 10% 47%	1890
July	1st to 10th	Night	5% 5% 2 6% 4 4 4 4 6% 9% 49%	5308
	11th to 20th	Night	6% 5% 2 7% 5% 5% 6% 5% 7% 10% 41%	5307
	21st to end	Night	6% 5% 2 5% 4 4 4 4 6% 9% 51%	5770
August	1st to 10th	Night	1 1 1 1 1 2 1 4 8% 79%	4156
	11th to 20th	Night	2 2 1 3 2 3 4 3 6% 12% 61%	4509
	21st to end	Night	2 2 1 3 2 3 3 3 6% 13% 62%	5494
September	1st to 10th	Night	7% 5% 2 5% 4 4 5% 5% 7% 10% 47%	2310
	11th to 20th	Night	7% 5% 2 7% 3 4 4 3 7% 8% 50%	2310
	21st to end	Night	7% 3 1 5% 3 3 5% 3 6% 8% 54%	2310
October	1st to 10th	Night	4 4 1 3 2 3 3 3 6% 6% 63%	2310
	11th to 20th	Night	9% 5% 2 4 3 3 3 2 3 6% 60%	2383
	21st to end	Night	10% 4 1 3 3 2 3 2 3 5% 64%	2640
November	1st to 10th	Night	11% 5% 2 5% 4 3 3 3 5% 5% 54%	2460
	11th to 20th	Night	12% 6% 2 5% 3 3 4 3 4 5% 52%	2520
	21st to end	Night	16% 6% 2 6% 4 4 3 3 5% 7% 43%	2716
December	1st to 10th	Night	32% 12% 3 6% 3 3 2 2 2 4 31%	4380
	11th to 20th	Night	14% 9% 2 7% 4 4 4 3 4 6% 44%	4946
	21st to end	Night	13% 6% 2 5% 3 3 3 3 4 6% 52%	6633

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	46% 3 7% 17% 17% 9%	5290
	11th to 20th	Day	38% 3 4 20% 22% 14%	5310
	21st to end	Day	51% 3 5% 13% 19% 9%	6206
February	1st to 10th	Day	46% 4 6% 10% 19% 14%	2100
	11th to 20th	Day	47% 4 8% 16% 15% 10%	2059
	21st to end	Day	41% 6% 7% 18% 17% 12%	1779
March	1st to 10th	Day	40% 5% 8% 18% 12% 16%	5046
	11th to 20th	Day	41% 4 5% 10% 17% 23%	5090
	21st to end	Day	41% 6% 8% 19% 18% 8%	5585
April	1st to 10th	Day	42% 7% 9% 15% 16% 11%	2310
	11th to 20th	Day	46% 6% 7% 17% 14% 11%	2286
	21st to end	Day	43% 6% 9% 18% 15% 9%	2541
May	1st to 10th	Day	49% 7% 12% 20% 10% 3	7655
	11th to 20th	Day	35% 7% 13% 22% 16% 7%	7631
	21st to end	Day	40% 8% 12% 31% 8% 1	8405
June	1st to 10th	Day	31% 9% 15% 27% 16% 1	2730
	11th to 20th	Day	35% 8% 13% 25% 16% 3	2730
	21st to end	Day	39% 10% 14% 26% 10% 1	2730
July	1st to 10th	Day	35% 8% 25% 28% 3	7616
	11th to 20th	Day	41% 9% 22% 21% 6%	7611
	21st to end	Day	31% 7% 17% 35% 10%	8155
August	1st to 10th	Day	16% 7% 17% 44% 16%	6000
	11th to 20th	Day	21% 10% 27% 35% 6%	5588
	21st to end	Day	30% 10% 17% 31% 11% 1	5620
September	1st to 10th	Day	43% 11% 12% 16% 14% 4	2310
	11th to 20th	Day	38% 8% 16% 21% 13% 3	2310
	21st to end	Day	33% 8% 12% 21% 16% 10%	2310
October	1st to 10th	Day	21% 5% 8% 14% 19% 34%	3700
	11th to 20th	Day	26% 5% 8% 20% 23% 18%	3315
	21st to end	Day	27% 5% 7% 19% 28% 14%	3538
November	1st to 10th	Day	38% 7% 9% 16% 20% 11%	2058
	11th to 20th	Day	37% 5% 9% 17% 19% 14%	2100
	21st to end	Day	45% 5% 7% 16% 15% 11%	1900
December	1st to 10th	Day	58% 3 5% 13% 16% 5%	3030
	11th to 20th	Day	43% 5% 6% 17% 17% 12%	3479
	21st to end	Day	36% 4 6% 21% 18% 15%	4587
January	1st to 10th	Night	43% 3 8% 15% 17% 13%	7635
	11th to 20th	Night	35% 3 4 18% 23% 17%	7680
	21st to end	Night	53% 3 5% 13% 16% 10%	8063
February	1st to 10th	Night	45% 3 9% 10% 16% 16%	2520
	11th to 20th	Night	42% 5% 8% 16% 17% 12%	2458
	21st to end	Night	44% 4 7% 17% 18% 11%	2024
March	1st to 10th	Night	48% 4 7% 16% 13% 12%	5029
	11th to 20th	Night	42% 4 6% 11% 16% 21%	5090
	21st to end	Night	42% 4 9% 18% 18% 9%	5588
April	1st to 10th	Night	44% 6% 11% 17% 13% 9%	2310
	11th to 20th	Night	44% 5% 9% 15% 13% 14%	2283
	21st to end	Night	47% 5% 11% 16% 13% 8%	2072
May	1st to 10th	Night	60% 6% 9% 14% 9% 3	5293
	11th to 20th	Night	40% 5% 11% 23% 15% 5%	5266
	21st to end	Night	47% 9% 15% 24% 5%	5805
June	1st to 10th	Night	27% 7% 20% 30% 16% 1	1890
	11th to 20th	Night	29% 7% 12% 31% 19% 3	1890
	21st to end	Night	30% 10% 22% 29% 9% 1	1890
July	1st to 10th	Night	31% 7% 29% 31% 2	5265
	11th to 20th	Night	36% 10% 29% 21% 4	5256
	21st to end	Night	30% 8% 20% 31% 11%	5641
August	1st to 10th	Night	7% 4 24% 50% 15%	4146
	11th to 20th	Night	16% 6% 38% 35% 5%	4538
	21st to end	Night	16% 9% 25% 39% 10% 1	5494
September	1st to 10th	Night	31% 10% 22% 21% 11% 4	2310
	11th to 20th	Night	30% 9% 18% 25% 14% 4	2310
	21st to end	Night	26% 7% 16% 26% 17% 8%	2310
October	1st to 10th	Night	16% 4 9% 18% 21% 32%	3700
	11th to 20th	Night	19% 4 9% 23% 28% 17%	3856
	21st to end	Night	20% 3 6% 26% 30% 15%	4252
November	1st to 10th	Night	32% 5% 11% 18% 23% 11%	2460
	11th to 20th	Night	35% 4 12% 17% 18% 15%	2520
	21st to end	Night	41% 4 10% 17% 17% 10%	2716
December	1st to 10th	Night	60% 3 6% 12% 12% 7%	4380
	11th to 20th	Night	42% 4 9% 14% 17% 15%	4947
	21st to end	Night	34% 5% 5% 18% 24% 14%	6633

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% 27% 8% 2	330
	11th to 20th	Day	22% 9% 33% 26% 8% 1	330
	21st to end	Day	21% 13% 33% 22% 11%	363
February	1st to 10th	Day	20% 13% 28% 27% 12%	330
	11th to 20th	Day	25% 13% 32% 21% 8% 1	330
	21st to end	Day	22% 12% 38% 22% 6%	273
March	1st to 10th	Day	18% 16% 36% 23% 6%	330
	11th to 20th	Day	16% 14% 41% 22% 7%	330
	21st to end	Day	16% 13% 36% 26% 9% 1	363
April	1st to 10th	Day	16% 16% 37% 24% 5% 1	330
	11th to 20th	Day	18% 15% 35% 22% 9% 1	324
	21st to end	Day	14% 11% 41% 26% 7%	561
May	1st to 10th	Day	16% 12% 41% 25% 6%	753
	11th to 20th	Day	11% 8% 36% 30% 12% 2	775
	21st to end	Day	10% 5% 34% 32% 18% 1	844
June	1st to 10th	Day	6% 2 19% 37% 29% 6%	780
	11th to 20th	Day	6% 2 17% 44% 25% 6%	780
	21st to end	Day	8% 3 13% 37% 28% 12%	780
July	1st to 10th	Day	9% 3 8% 34% 33% 14%	771
	11th to 20th	Day	6% 1 6% 34% 41% 12%	768
	21st to end	Day	6% 1 5% 36% 37% 16%	849
August	1st to 10th	Day	3 1 4 32% 39% 21%	776
	11th to 20th	Day	2 1 5% 38% 33% 20%	587
	21st to end	Day	6% 1 5% 24% 33% 31%	426
September	1st to 10th	Day	9% 6% 22% 39% 24%	360
	11th to 20th	Day	7% 1 5% 23% 42% 22%	360
	21st to end	Day	7% 1 5% 29% 39% 19%	360
October	1st to 10th	Day	5% 2 13% 32% 36% 12%	360
	11th to 20th	Day	10% 2 13% 34% 28% 13%	339
	21st to end	Day	12% 8% 21% 31% 19% 9%	363
November	1st to 10th	Day	14% 5% 19% 31% 24% 7%	330
	11th to 20th	Day	17% 5% 25% 27% 22% 5%	330
	21st to end	Day	21% 12% 32% 20% 11% 3	330
December	1st to 10th	Day	22% 7% 24% 32% 12% 3	330
	11th to 20th	Day	22% 11% 27% 25% 13% 2	330
	21st to end	Day	20% 7% 32% 26% 13% 2	363
January	1st to 10th	Night	24% 8% 29% 29% 10%	1050
	11th to 20th	Night	21% 9% 28% 35% 8%	1050
	21st to end	Night	24% 8% 29% 32% 6%	1034
February	1st to 10th	Night	24% 11% 28% 30% 5%	840
	11th to 20th	Night	23% 11% 31% 29% 5%	824
	21st to end	Night	27% 8% 36% 25% 5%	640
March	1st to 10th	Night	28% 9% 30% 29% 5%	630
	11th to 20th	Night	22% 10% 30% 32% 5%	630
	21st to end	Night	19% 9% 34% 32% 6%	693
April	1st to 10th	Night	18% 8% 42% 28% 5%	630
	11th to 20th	Night	22% 10% 33% 29% 6%	623
	21st to end	Night	20% 10% 39% 26% 6%	630
May	1st to 10th	Night	18% 8% 40% 29% 4	630
	11th to 20th	Night	13% 5% 32% 40% 10% 1	621
	21st to end	Night	10% 4 30% 40% 14%	683
June	1st to 10th	Night	7% 2 16% 49% 25% 1	630
	11th to 20th	Night	8% 1 17% 52% 22% 1	630
	21st to end	Night	9% 1 11% 41% 35% 3	630
July	1st to 10th	Night	8% 1 7% 44% 35% 5%	615
	11th to 20th	Night	2 1 7% 40% 45% 5%	612
	21st to end	Night	4 1 5% 43% 42% 5%	690
August	1st to 10th	Night	1 3 42% 48% 5%	627
	11th to 20th	Night	3 5% 40% 46% 5%	624
	21st to end	Night	4 1 4 30% 53% 8%	693
September	1st to 10th	Night	9% 1 4 32% 47% 7%	630
	11th to 20th	Night	9% 2 4 33% 47% 5%	630
	21st to end	Night	8% 1 9% 31% 47% 4	630
October	1st to 10th	Night	7% 1 8% 40% 41% 3	630
	11th to 20th	Night	11% 3 18% 44% 22% 2	759
	21st to end	Night	10% 5% 24% 38% 21% 1	880
November	1st to 10th	Night	11% 5% 20% 41% 21% 1	820
	11th to 20th	Night	16% 5% 22% 38% 17% 1	840
	21st to end	Night	18% 7% 28% 30% 15% 1	1036
December	1st to 10th	Night	24% 7% 24% 31% 13% 1	1050
	11th to 20th	Night	22% 9% 27% 31% 10% 1	1050
	21st to end	Night	21% 8% 27% 34% 9% 1	1155

Page generated at 2026-10-11 04:06:28. Version ac07

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