Texas Yard Canon Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Texas Yard Canon Observatory clear sky chart from 2005-11-06 to 2024-01-13.

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	13% 9% 4 7% 6% 3 5% 5% 5% 7% 37%	74802
	Night	14% 9% 4 6% 5% 3 4 4 5% 7% 39%	74967
Transparency	Day	45% 7% 13% 21% 12% 1	74503
	Night	45% 7% 12% 22% 13% 2	74787
Seeing	Day	16% 12% 29% 26% 13% 5%	14705
	Night	18% 10% 31% 28% 12% 1	24691

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	11% 12% 6% 8% 6% 3 6% 5% 4 7% 32%	1517
	11th to 20th	Day	13% 15% 8% 11% 7% 3 4 4 4 7% 24%	1461
	21st to end	Day	13% 14% 7% 11% 8% 4 5% 4 4 7% 23%	1606
February	1st to 10th	Day	12% 14% 6% 8% 6% 3 6% 5% 4 6% 30%	1620
	11th to 20th	Day	14% 11% 3 6% 6% 4 6% 5% 5% 5% 36%	1745
	21st to end	Day	12% 14% 5% 11% 6% 4 5% 4 4 5% 29%	1480
March	1st to 10th	Day	14% 11% 5% 9% 6% 3 5% 5% 5% 6% 32%	1800
	11th to 20th	Day	13% 9% 4 7% 6% 3 4 3 5% 7% 39%	1857
	21st to end	Day	18% 11% 5% 7% 6% 3 5% 5% 4 7% 28%	2376
April	1st to 10th	Day	17% 12% 5% 6% 6% 4 5% 4 6% 5% 30%	2160
	11th to 20th	Day	15% 11% 4 7% 5% 3 5% 5% 5% 7% 33%	2134
	21st to end	Day	19% 9% 3 6% 5% 3 4 5% 5% 6% 34%	2268
May	1st to 10th	Day	16% 9% 3 7% 6% 4 5% 4 7% 7% 31%	2340
	11th to 20th	Day	18% 8% 3 5% 5% 3 5% 4 5% 8% 35%	2479
	21st to end	Day	13% 6% 3 6% 6% 3 5% 6% 5% 8% 38%	2725
June	1st to 10th	Day	10% 5% 2 5% 5% 4 5% 5% 5% 9% 45%	2520
	11th to 20th	Day	12% 5% 2 5% 5% 3 4 4 6% 10% 44%	2520
	21st to end	Day	12% 5% 2 6% 6% 4 5% 5% 7% 9% 41%	2520
July	1st to 10th	Day	7% 5% 2 4 5% 3 5% 6% 7% 9% 47%	2520
	11th to 20th	Day	8% 3 3 5% 5% 4 5% 6% 6% 9% 46%	2520
	21st to end	Day	6% 4 2 5% 5% 3 5% 5% 6% 10% 46%	2743
August	1st to 10th	Day	8% 4 2 5% 6% 3 6% 5% 7% 11% 42%	2503
	11th to 20th	Day	10% 5% 3 6% 5% 4 5% 6% 6% 9% 42%	2156
	21st to end	Day	9% 5% 2 5% 5% 3 5% 5% 6% 8% 46%	2376
September	1st to 10th	Day	12% 6% 2 6% 4 4 5% 5% 6% 8% 42%	2160
	11th to 20th	Day	12% 5% 2 4 4 2 4 4 5% 8% 48%	2059
	21st to end	Day	12% 6% 3 6% 5% 3 4 5% 7% 7% 42%	1980
October	1st to 10th	Day	15% 7% 2 6% 4 2 4 4 5% 6% 45%	1908
	11th to 20th	Day	20% 8% 3 7% 6% 3 4 5% 5% 7% 32%	1782
	21st to end	Day	19% 9% 3 7% 5% 3 4 3 5% 6% 37%	1782
November	1st to 10th	Day	11% 9% 4 5% 5% 3 4 4 5% 6% 44%	1672
	11th to 20th	Day	12% 10% 5% 8% 6% 4 5% 5% 5% 7% 32%	1710
	21st to end	Day	18% 10% 3 7% 5% 2 4 3 4 6% 37%	1582
December	1st to 10th	Day	14% 10% 4 10% 8% 4 6% 5% 5% 6% 30%	1520
	11th to 20th	Day	13% 12% 5% 9% 6% 4 5% 6% 6% 6% 28%	1918
	21st to end	Day	19% 21% 9% 11% 6% 3 4 4 4 4 16%	2783
January	1st to 10th	Night	13% 11% 7% 8% 6% 4 4 3 4 5% 35%	2648
	11th to 20th	Night	15% 14% 6% 10% 7% 3 4 4 5% 6% 27%	2561
	21st to end	Night	14% 11% 7% 10% 7% 3 5% 6% 6% 7% 26%	2745
February	1st to 10th	Night	13% 13% 6% 9% 6% 3 3 4 4 6% 32%	2340
	11th to 20th	Night	13% 9% 3 6% 6% 4 4 5% 6% 5% 39%	2100
	21st to end	Night	17% 11% 3 6% 5% 4 4 4 5% 6% 34%	1776
March	1st to 10th	Night	16% 10% 4 6% 6% 3 5% 4 5% 7% 35%	2160
	11th to 20th	Night	13% 7% 2 4 5% 2 4 5% 5% 8% 43%	2118
	21st to end	Night	18% 10% 4 7% 6% 4 4 4 4 6% 34%	1980
April	1st to 10th	Night	16% 9% 3 5% 5% 4 5% 5% 6% 7% 35%	1800
	11th to 20th	Night	20% 8% 3 6% 6% 2 5% 4 4 5% 37%	1775
	21st to end	Night	19% 8% 3 4 4 3 4 5% 5% 6% 38%	1690
May	1st to 10th	Night	16% 8% 3 6% 5% 3 5% 6% 6% 9% 34%	1616
	11th to 20th	Night	17% 7% 3 5% 5% 2 4 4 6% 7% 39%	1416
	21st to end	Night	12% 7% 3 6% 5% 3 5% 5% 5% 7% 42%	1551
June	1st to 10th	Night	10% 4 2 5% 4 3 4 5% 7% 8% 48%	1440
	11th to 20th	Night	12% 5% 2 5% 5% 3 4 5% 7% 7% 46%	1440
	21st to end	Night	9% 4 2 5% 6% 2 5% 5% 5% 9% 47%	1440
July	1st to 10th	Night	6% 3 2 5% 4 2 4 5% 6% 10% 53%	1440
	11th to 20th	Night	7% 3 1 5% 4 2 4 4 6% 9% 54%	1440
	21st to end	Night	5% 3 2 4 4 3 5% 4 8% 10% 51%	1575
August	1st to 10th	Night	6% 3 2 4 5% 3 5% 5% 6% 9% 51%	1436
	11th to 20th	Night	8% 4 2 5% 4 2 4 4 7% 9% 51%	1742
	21st to end	Night	9% 4 2 5% 5% 2 4 4 5% 7% 53%	1980
September	1st to 10th	Night	8% 5% 2 5% 5% 2 4 4 5% 7% 52%	1800
	11th to 20th	Night	11% 4 2 5% 4 2 4 4 4 7% 54%	1882
	21st to end	Night	12% 6% 2 6% 4 3 3 4 5% 6% 48%	1980
October	1st to 10th	Night	12% 6% 3 5% 4 3 4 4 5% 5% 49%	2051
	11th to 20th	Night	17% 7% 3 5% 5% 3 4 4 4 7% 43%	2178
	21st to end	Night	20% 8% 3 5% 6% 3 3 5% 5% 7% 36%	2574
November	1st to 10th	Night	12% 7% 3 5% 5% 3 3 5% 4 6% 47%	2406
	11th to 20th	Night	14% 9% 5% 6% 6% 4 5% 4 5% 6% 35%	2470
	21st to end	Night	17% 9% 3 5% 5% 3 4 5% 5% 6% 37%	2594
December	1st to 10th	Night	15% 11% 5% 7% 6% 4 5% 5% 5% 6% 31%	2660
	11th to 20th	Night	15% 12% 5% 9% 6% 3 5% 5% 5% 5% 29%	3279
	21st to end	Night	21% 18% 5% 9% 6% 3 4 4 4 5% 19%	4884

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	52% 7% 13% 17% 10%	1518
	11th to 20th	Day	61% 6% 10% 15% 7%	1461
	21st to end	Day	62% 6% 10% 13% 9%	1606
February	1st to 10th	Day	55% 7% 12% 17% 8% 1	1620
	11th to 20th	Day	50% 6% 11% 21% 10% 2	1755
	21st to end	Day	56% 6% 9% 16% 10% 2	1480
March	1st to 10th	Day	53% 7% 11% 20% 8% 2	1800
	11th to 20th	Day	46% 6% 13% 21% 13% 2	1857
	21st to end	Day	57% 6% 13% 17% 6% 1	2376
April	1st to 10th	Day	55% 7% 11% 17% 10%	2160
	11th to 20th	Day	48% 7% 11% 19% 12% 3	2134
	21st to end	Day	49% 9% 12% 17% 12% 1	2268
May	1st to 10th	Day	49% 8% 14% 21% 7%	2340
	11th to 20th	Day	46% 8% 13% 22% 10% 1	2483
	21st to end	Day	43% 8% 14% 20% 13% 1	2725
June	1st to 10th	Day	35% 8% 14% 25% 16% 2	2520
	11th to 20th	Day	35% 7% 15% 23% 18% 2	2520
	21st to end	Day	38% 9% 15% 22% 15% 1	2520
July	1st to 10th	Day	31% 7% 15% 31% 13% 2	2451
	11th to 20th	Day	32% 9% 16% 26% 16% 2	2445
	21st to end	Day	30% 9% 17% 26% 15% 3	2591
August	1st to 10th	Day	34% 10% 16% 27% 12% 1	2488
	11th to 20th	Day	36% 10% 17% 24% 12% 1	2156
	21st to end	Day	33% 8% 14% 25% 18% 2	2376
September	1st to 10th	Day	38% 8% 13% 24% 16% 2	2160
	11th to 20th	Day	33% 6% 14% 31% 15% 2	2059
	21st to end	Day	38% 8% 13% 29% 13% 1	1980
October	1st to 10th	Day	40% 6% 11% 28% 15% 1	1908
	11th to 20th	Day	50% 6% 13% 19% 11% 1	1782
	21st to end	Day	49% 7% 11% 22% 11% 1	1782
November	1st to 10th	Day	41% 6% 14% 23% 15% 1	1672
	11th to 20th	Day	50% 7% 13% 20% 9% 1	1710
	21st to end	Day	49% 5% 14% 25% 7%	1582
December	1st to 10th	Day	54% 7% 14% 16% 8% 1	1520
	11th to 20th	Day	53% 7% 15% 16% 7% 2	1915
	21st to end	Day	72% 6% 9% 9% 5%	2783
January	1st to 10th	Night	52% 5% 10% 20% 12% 1	2648
	11th to 20th	Night	58% 7% 13% 14% 8% 1	2561
	21st to end	Night	55% 8% 12% 14% 10% 1	2745
February	1st to 10th	Night	54% 6% 11% 17% 11% 2	2340
	11th to 20th	Night	45% 6% 13% 20% 15% 2	2101
	21st to end	Night	51% 5% 11% 18% 11% 4	1776
March	1st to 10th	Night	50% 6% 13% 19% 9% 2	2160
	11th to 20th	Night	39% 7% 14% 22% 15% 3	2118
	21st to end	Night	52% 6% 11% 20% 10% 2	1980
April	1st to 10th	Night	46% 9% 10% 19% 15% 1	1800
	11th to 20th	Night	49% 5% 7% 18% 17% 4	1775
	21st to end	Night	43% 8% 13% 19% 15% 2	1690
May	1st to 10th	Night	46% 8% 13% 21% 11% 1	1616
	11th to 20th	Night	43% 6% 13% 22% 13% 2	1417
	21st to end	Night	40% 7% 12% 24% 15% 2	1552
June	1st to 10th	Night	31% 8% 14% 27% 18% 2	1440
	11th to 20th	Night	35% 6% 12% 23% 21% 2	1440
	21st to end	Night	34% 8% 16% 23% 17% 3	1440
July	1st to 10th	Night	27% 7% 17% 29% 17% 4	1400
	11th to 20th	Night	27% 8% 13% 30% 20% 3	1392
	21st to end	Night	24% 10% 16% 28% 17% 5%	1487
August	1st to 10th	Night	27% 9% 16% 29% 15% 3	1427
	11th to 20th	Night	28% 8% 17% 30% 16% 1	1742
	21st to end	Night	29% 7% 13% 28% 20% 3	1980
September	1st to 10th	Night	32% 7% 12% 25% 22% 2	1800
	11th to 20th	Night	30% 7% 10% 33% 18% 2	1882
	21st to end	Night	37% 5% 10% 30% 16% 1	1980
October	1st to 10th	Night	36% 7% 10% 29% 17% 2	2051
	11th to 20th	Night	43% 6% 12% 22% 17% 1	2178
	21st to end	Night	47% 6% 12% 22% 11% 1	2574
November	1st to 10th	Night	37% 7% 10% 26% 17% 3	2406
	11th to 20th	Night	48% 6% 14% 20% 11% 1	2470
	21st to end	Night	47% 6% 15% 21% 10% 1	2594
December	1st to 10th	Night	53% 8% 10% 19% 9% 1	2660
	11th to 20th	Night	55% 7% 11% 17% 9% 1	3281
	21st to end	Night	66% 6% 10% 13% 5%	4884

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	16% 18% 35% 24% 6% 1	270
	11th to 20th	Day	21% 17% 36% 21% 4 1	248
	21st to end	Day	20% 16% 38% 20% 5% 1	264
February	1st to 10th	Day	15% 21% 45% 14% 5%	240
	11th to 20th	Day	23% 25% 33% 16% 3	240
	21st to end	Day	22% 25% 40% 12% 2	198
March	1st to 10th	Day	19% 24% 40% 14% 3	240
	11th to 20th	Day	24% 21% 28% 22% 5% 1	253
	21st to end	Day	27% 14% 29% 21% 7% 2	462
April	1st to 10th	Day	23% 15% 34% 23% 5%	420
	11th to 20th	Day	21% 22% 25% 20% 9% 3	412
	21st to end	Day	23% 12% 28% 22% 13% 1	420
May	1st to 10th	Day	21% 13% 32% 25% 8% 2	423
	11th to 20th	Day	23% 12% 30% 24% 9% 3	625
	21st to end	Day	17% 9% 29% 26% 13% 6%	679
June	1st to 10th	Day	9% 8% 32% 32% 14% 6%	630
	11th to 20th	Day	14% 8% 27% 32% 13% 6%	630
	21st to end	Day	14% 7% 30% 31% 13% 5%	630
July	1st to 10th	Day	7% 4 21% 32% 26% 10%	621
	11th to 20th	Day	9% 6% 26% 35% 17% 7%	618
	21st to end	Day	5% 4 30% 38% 16% 8%	684
August	1st to 10th	Day	9% 2 21% 36% 20% 11%	622
	11th to 20th	Day	10% 6% 16% 30% 25% 13%	439
	21st to end	Day	9% 6% 23% 31% 24% 8%	495
September	1st to 10th	Day	15% 7% 21% 29% 21% 7%	450
	11th to 20th	Day	12% 4 22% 30% 23% 10%	450
	21st to end	Day	16% 12% 22% 25% 17% 8%	450
October	1st to 10th	Day	19% 11% 25% 26% 14% 5%	378
	11th to 20th	Day	23% 20% 29% 20% 7%	270
	21st to end	Day	28% 16% 34% 15% 5% 1	297
November	1st to 10th	Day	17% 17% 34% 21% 9% 1	270
	11th to 20th	Day	20% 20% 35% 18% 7%	270
	21st to end	Day	23% 15% 40% 18% 4	270
December	1st to 10th	Day	20% 19% 40% 14% 6% 1	270
	11th to 20th	Day	18% 20% 36% 18% 8% 1	270
	21st to end	Day	25% 23% 36% 14% 1	297
January	1st to 10th	Night	19% 17% 36% 22% 6%	950
	11th to 20th	Night	22% 14% 35% 22% 6% 1	915
	21st to end	Night	18% 11% 39% 25% 6%	990
February	1st to 10th	Night	22% 13% 36% 25% 4	900
	11th to 20th	Night	19% 17% 35% 25% 5%	705
	21st to end	Night	24% 14% 38% 19% 5%	592
March	1st to 10th	Night	21% 13% 34% 23% 8% 1	720
	11th to 20th	Night	17% 13% 35% 27% 8%	691
	21st to end	Night	22% 9% 31% 30% 8% 1	594
April	1st to 10th	Night	21% 12% 35% 25% 7%	540
	11th to 20th	Night	23% 12% 31% 26% 7% 2	533
	21st to end	Night	22% 10% 31% 26% 10% 1	540
May	1st to 10th	Night	19% 9% 34% 31% 6% 1	540
	11th to 20th	Night	19% 5% 30% 33% 12%	531
	21st to end	Night	13% 5% 28% 34% 19% 1	584
June	1st to 10th	Night	10% 4 27% 42% 16% 1	540
	11th to 20th	Night	14% 4 31% 36% 14% 1	540
	21st to end	Night	9% 4 27% 42% 17% 1	540
July	1st to 10th	Night	7% 2 18% 39% 31% 3	525
	11th to 20th	Night	8% 2 22% 41% 24% 3	522
	21st to end	Night	6% 3 19% 47% 24% 2	591
August	1st to 10th	Night	7% 2 14% 49% 26% 2	537
	11th to 20th	Night	9% 3 16% 38% 29% 6%	534
	21st to end	Night	10% 3 18% 40% 28% 3	594
September	1st to 10th	Night	9% 4 22% 37% 23% 5%	540
	11th to 20th	Night	13% 5% 23% 29% 27% 4	622
	21st to end	Night	15% 8% 26% 27% 22% 3	720
October	1st to 10th	Night	15% 8% 28% 29% 18% 2	720
	11th to 20th	Night	21% 11% 32% 26% 9%	720
	21st to end	Night	24% 10% 32% 25% 9%	792
November	1st to 10th	Night	17% 11% 37% 24% 10% 1	740
	11th to 20th	Night	19% 16% 35% 23% 6%	760
	21st to end	Night	22% 14% 36% 22% 6%	884
December	1st to 10th	Night	21% 15% 38% 21% 5%	950
	11th to 20th	Night	23% 13% 36% 22% 5%	950
	21st to end	Night	29% 14% 35% 19% 3	1045

Page generated at 2024-01-10 18:35:24. Version ac07

Copyright 2024 Attilla Danko