Edinburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Edinburg clear sky chart from 2005-11-06 to 2024-11-28.

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
Transparency	Day	33% 8% 14% 23% 16% 7%	104938
	Night	33% 7% 16% 22% 15% 7%	102820
Seeing	Day	10% 4 20% 34% 24% 9%	14367
	Night	13% 4 23% 38% 20% 2	24386

By Month

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	35% 8% 8% 17% 20% 13%	2848
	11th to 20th	Day	35% 6% 9% 19% 19% 11%	2992
	21st to end	Day	44% 8% 9% 14% 18% 7%	3487
February	1st to 10th	Day	42% 4 9% 16% 17% 12%	1900
	11th to 20th	Day	37% 5% 10% 20% 19% 9%	1859
	21st to end	Day	35% 5% 9% 21% 19% 9%	1588
March	1st to 10th	Day	43% 9% 12% 20% 12% 5%	3436
	11th to 20th	Day	53% 7% 10% 12% 13% 6%	3480
	21st to end	Day	24% 6% 10% 25% 18% 16%	3814
April	1st to 10th	Day	35% 7% 12% 21% 16% 9%	2090
	11th to 20th	Day	37% 8% 12% 20% 15% 7%	2066
	21st to end	Day	33% 9% 12% 19% 18% 9%	2171
May	1st to 10th	Day	30% 11% 18% 25% 10% 5%	4120
	11th to 20th	Day	31% 11% 14% 22% 15% 8%	4086
	21st to end	Day	21% 8% 12% 37% 20% 2	4489
June	1st to 10th	Day	24% 8% 14% 30% 21% 3	2470
	11th to 20th	Day	25% 9% 14% 24% 24% 5%	2470
	21st to end	Day	33% 11% 19% 25% 11% 1	2470
July	1st to 10th	Day	34% 10% 20% 31% 6%	4056
	11th to 20th	Day	37% 10% 26% 18% 8% 1	4051
	21st to end	Day	36% 9% 23% 26% 7%	4275
August	1st to 10th	Day	12% 6% 21% 45% 15%	3772
	11th to 20th	Day	22% 11% 35% 27% 6%	3762
	21st to end	Day	26% 11% 23% 29% 10% 1	3891
September	1st to 10th	Day	43% 11% 16% 17% 12% 2	2090
	11th to 20th	Day	44% 12% 15% 17% 9% 3	2090
	21st to end	Day	35% 10% 15% 21% 13% 6%	2090
October	1st to 10th	Day	25% 6% 8% 14% 26% 21%	3480
	11th to 20th	Day	27% 7% 10% 17% 24% 16%	3339
	21st to end	Day	23% 6% 9% 21% 29% 12%	3428
November	1st to 10th	Day	32% 7% 11% 22% 20% 6%	1958
	11th to 20th	Day	41% 5% 7% 19% 19% 9%	2000
	21st to end	Day	37% 5% 11% 19% 18% 11%	1816
December	1st to 10th	Day	39% 6% 10% 23% 15% 7%	1710
	11th to 20th	Day	40% 8% 11% 12% 16% 13%	2159
	21st to end	Day	41% 6% 7% 21% 19% 6%	3135
January	1st to 10th	Night	37% 6% 8% 17% 17% 15%	4108
	11th to 20th	Night	38% 6% 7% 17% 19% 12%	3992
	21st to end	Night	52% 6% 8% 12% 14% 7%	4180
February	1st to 10th	Night	41% 6% 10% 17% 13% 14%	2280
	11th to 20th	Night	40% 7% 10% 18% 16% 9%	2218
	21st to end	Night	38% 6% 10% 18% 20% 9%	1865
March	1st to 10th	Night	45% 8% 12% 19% 11% 5%	3419
	11th to 20th	Night	54% 9% 13% 10% 9% 5%	3480
	21st to end	Night	26% 5% 11% 24% 22% 11%	3817
April	1st to 10th	Night	38% 7% 16% 19% 13% 6%	2090
	11th to 20th	Night	41% 8% 13% 17% 13% 8%	2063
	21st to end	Night	41% 10% 12% 17% 14% 7%	2000
May	1st to 10th	Night	39% 12% 18% 18% 9% 4	2850
	11th to 20th	Night	42% 11% 15% 19% 9% 3	2824
	21st to end	Night	29% 10% 18% 33% 9%	3099
June	1st to 10th	Night	18% 9% 20% 31% 20% 2	1710
	11th to 20th	Night	21% 8% 13% 34% 21% 3	1710
	21st to end	Night	25% 10% 24% 30% 10% 1	1710
July	1st to 10th	Night	29% 10% 29% 27% 4	2805
	11th to 20th	Night	33% 10% 32% 20% 5%	2796
	21st to end	Night	27% 9% 33% 26% 5%	3044
August	1st to 10th	Night	7% 5% 27% 52% 9%	3144
	11th to 20th	Night	19% 8% 42% 28% 3	3143
	21st to end	Night	15% 8% 34% 32% 10% 1	3765
September	1st to 10th	Night	31% 10% 22% 24% 10% 1	2090
	11th to 20th	Night	32% 11% 21% 24% 10% 2	2090
	21st to end	Night	26% 10% 18% 28% 13% 5%	2090
October	1st to 10th	Night	18% 5% 9% 19% 28% 22%	3480
	11th to 20th	Night	23% 5% 11% 19% 25% 17%	3545
	21st to end	Night	25% 5% 8% 22% 30% 10%	4120
November	1st to 10th	Night	28% 6% 13% 22% 23% 8%	2340
	11th to 20th	Night	37% 6% 12% 19% 18% 9%	2400
	21st to end	Night	36% 5% 13% 20% 16% 10%	2514
December	1st to 10th	Night	39% 6% 10% 20% 17% 7%	2470
	11th to 20th	Night	38% 7% 10% 17% 13% 15%	3037
	21st to end	Night	41% 6% 11% 14% 18% 10%	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	19% 6% 29% 27% 16% 4	270
	11th to 20th	Day	18% 7% 29% 34% 9% 4	270
	21st to end	Day	23% 6% 33% 26% 10% 2	297
February	1st to 10th	Day	15% 8% 33% 26% 17% 1	270
	11th to 20th	Day	18% 6% 36% 30% 9% 1	270
	21st to end	Day	15% 6% 40% 32% 7% 1	225
March	1st to 10th	Day	16% 7% 31% 34% 12% 1	270
	11th to 20th	Day	19% 7% 34% 30% 9% 1	270
	21st to end	Day	9% 10% 40% 35% 6%	297
April	1st to 10th	Day	13% 8% 34% 33% 11% 1	270
	11th to 20th	Day	9% 11% 31% 33% 13% 3	264
	21st to end	Day	10% 8% 39% 32% 10% 1	351
May	1st to 10th	Day	10% 4 40% 33% 12% 1	653
	11th to 20th	Day	9% 5% 38% 35% 13% 1	675
	21st to end	Day	4 4 31% 42% 18% 2	734
June	1st to 10th	Day	3 1 16% 39% 33% 8%	680
	11th to 20th	Day	5% 1 14% 48% 27% 6%	680
	21st to end	Day	6% 1 12% 43% 27% 12%	680
July	1st to 10th	Day	7% 1 8% 37% 36% 10%	671
	11th to 20th	Day	4 1 5% 40% 40% 11%	668
	21st to end	Day	5% 1 5% 39% 38% 12%	712
August	1st to 10th	Day	2 5% 45% 34% 14%	487
	11th to 20th	Day	3 1 4 44% 34% 15%	477
	21st to end	Day	2 1 6% 24% 34% 33%	368
September	1st to 10th	Day	13% 1 4 22% 38% 22%	300
	11th to 20th	Day	8% 1 3 20% 33% 35%	300
	21st to end	Day	6% 1 7% 21% 40% 26%	300
October	1st to 10th	Day	9% 2 6% 23% 35% 25%	300
	11th to 20th	Day	10% 1 8% 28% 36% 18%	300
	21st to end	Day	12% 4 18% 31% 28% 8%	330
November	1st to 10th	Day	13% 5% 10% 36% 30% 6%	300
	11th to 20th	Day	24% 4 13% 23% 24% 11%	300
	21st to end	Day	24% 6% 25% 20% 14% 10%	291
December	1st to 10th	Day	23% 3 21% 26% 20% 8%	270
	11th to 20th	Day	18% 8% 26% 24% 19% 5%	270
	21st to end	Day	23% 4 21% 33% 15% 4	297
January	1st to 10th	Night	21% 6% 25% 34% 13% 1	950
	11th to 20th	Night	22% 5% 25% 39% 9%	874
	21st to end	Night	23% 5% 26% 37% 9%	836
February	1st to 10th	Night	21% 5% 34% 34% 7%	760
	11th to 20th	Night	21% 6% 35% 32% 6%	744
	21st to end	Night	20% 5% 43% 26% 6%	609
March	1st to 10th	Night	16% 9% 35% 34% 5%	570
	11th to 20th	Night	16% 7% 41% 30% 6%	570
	21st to end	Night	12% 7% 47% 31% 3	627
April	1st to 10th	Night	14% 5% 46% 30% 5%	570
	11th to 20th	Night	15% 9% 38% 33% 5%	563
	21st to end	Night	14% 6% 44% 32% 4	570
May	1st to 10th	Night	12% 6% 48% 29% 5%	570
	11th to 20th	Night	10% 6% 35% 43% 5%	561
	21st to end	Night	6% 3 31% 48% 12%	617
June	1st to 10th	Night	4 2 13% 55% 26% 1	570
	11th to 20th	Night	4 1 16% 57% 21% 1	570
	21st to end	Night	6% 2 13% 45% 32% 2	570
July	1st to 10th	Night	8% 1 9% 51% 28% 3	555
	11th to 20th	Night	4 2 6% 50% 36% 2	552
	21st to end	Night	4 1 6% 53% 35% 2	624
August	1st to 10th	Night	1 5% 53% 39% 2	567
	11th to 20th	Night	2 1 7% 46% 40% 4	564
	21st to end	Night	4 1 5% 33% 50% 7%	627
September	1st to 10th	Night	7% 1 5% 31% 48% 8%	570
	11th to 20th	Night	11% 1 6% 23% 51% 8%	570
	21st to end	Night	8% 1 6% 33% 46% 7%	570
October	1st to 10th	Night	5% 1 5% 35% 47% 7%	570
	11th to 20th	Night	11% 1 12% 40% 33% 2	617
	21st to end	Night	8% 4 20% 43% 24% 2	836
November	1st to 10th	Night	10% 3 18% 43% 24% 2	780
	11th to 20th	Night	18% 3 19% 38% 22% 1	800
	21st to end	Night	19% 4 22% 37% 16% 1	938
December	1st to 10th	Night	19% 3 22% 38% 16% 2	950
	11th to 20th	Night	20% 6% 25% 35% 14% 1	950
	21st to end	Night	19% 6% 26% 37% 12%	1045

Page generated at 2024-11-24 23:22:18. Version ac07

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