Carrizo Springs City Hall
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carrizo Springs City Hall clear sky chart from 2005-11-06 to 2026-06-01.

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% 5% 2 5% 3 3 3 3 5% 7% 51%	132470
	Night	11% 4 2 4 3 3 3 3 5% 7% 55%	131035
Transparency	Day	31% 5% 10% 21% 19% 12%	136359
	Night	29% 5% 11% 21% 20% 14%	135208
Seeing	Day	11% 4 17% 33% 27% 8%	16616
	Night	12% 4 23% 45% 16% 1	26658

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	13% 5% 2 4 2 2 3 2 3 4 59%	5289
	11th to 20th	Day	12% 6% 2 5% 3 2 2 2 4 5% 56%	5772
	21st to end	Day	19% 8% 2 5% 3 3 3 2 5% 7% 45%	6468
February	1st to 10th	Day	13% 7% 3 6% 3 3 3 3 5% 5% 48%	2100
	11th to 20th	Day	13% 6% 2 5% 3 3 3 3 5% 6% 50%	2049
	21st to end	Day	12% 6% 2 4 3 3 3 3 5% 6% 54%	1730
March	1st to 10th	Day	12% 5% 2 4 3 3 4 3 4 7% 53%	4748
	11th to 20th	Day	14% 6% 2 5% 2 2 3 2 3 5% 56%	5090
	21st to end	Day	13% 6% 2 5% 3 2 3 2 4 7% 52%	5583
April	1st to 10th	Day	11% 7% 2 5% 4 3 3 3 5% 7% 49%	2310
	11th to 20th	Day	14% 4 2 5% 4 4 4 4 5% 6% 49%	2472
	21st to end	Day	13% 6% 2 5% 4 4 3 3 5% 7% 47%	2520
May	1st to 10th	Day	16% 6% 3 7% 4 4 4 3 5% 7% 41%	5894
	11th to 20th	Day	8% 4 2 4 4 3 4 3 5% 9% 54%	5992
	21st to end	Day	9% 6% 2 6% 4 5% 4 4 6% 10% 43%	6577
June	1st to 10th	Day	4 3 1 4 3 4 4 3 7% 10% 57%	2601
	11th to 20th	Day	4 4 2 4 3 4 5% 4 6% 8% 56%	2600
	21st to end	Day	5% 5% 2 5% 5% 6% 6% 5% 8% 10% 46%	2600
July	1st to 10th	Day	10% 7% 2 7% 5% 4 4 4 5% 8% 43%	5900
	11th to 20th	Day	5% 5% 2 5% 4 4 4 4 6% 9% 51%	5900
	21st to end	Day	5% 4 2 5% 4 5% 4 4 7% 10% 51%	6108
August	1st to 10th	Day	1 1 2 1 2 2 2 4 7% 78%	3905
	11th to 20th	Day	2 2 1 3 2 2 3 3 6% 10% 65%	3846
	21st to end	Day	4 3 1 4 3 4 4 4 6% 11% 55%	4289
September	1st to 10th	Day	10% 6% 2 6% 5% 5% 5% 4 6% 7% 44%	2200
	11th to 20th	Day	11% 5% 2 6% 5% 4 5% 4 6% 9% 42%	2200
	21st to end	Day	8% 4 1 5% 4 4 4 4 5% 8% 53%	2200
October	1st to 10th	Day	5% 4 1 4 3 4 4 3 4 8% 59%	2200
	11th to 20th	Day	12% 5% 2 5% 3 4 3 3 4 6% 52%	2200
	21st to end	Day	11% 3 1 3 4 3 3 2 3 5% 62%	2228
November	1st to 10th	Day	15% 6% 2 5% 3 3 3 2 4 7% 49%	2021
	11th to 20th	Day	14% 6% 2 5% 2 3 3 3 4 6% 53%	1890
	21st to end	Day	16% 7% 2 5% 4 3 3 3 4 6% 46%	1890
December	1st to 10th	Day	31% 9% 3 5% 3 3 3 2 3 5% 33%	3030
	11th to 20th	Day	16% 8% 2 6% 4 4 4 3 5% 5% 42%	3481
	21st to end	Day	10% 6% 2 5% 3 3 3 2 4 5% 57%	4587
January	1st to 10th	Night	13% 5% 1 4 2 2 3 2 4 6% 58%	7634
	11th to 20th	Night	13% 4 1 3 2 3 3 2 3 5% 61%	7260
	21st to end	Night	24% 5% 2 5% 3 2 3 3 3 5% 46%	7746
February	1st to 10th	Night	10% 5% 1 4 3 3 4 3 4 5% 57%	2520
	11th to 20th	Night	16% 5% 1 4 2 2 3 2 4 5% 54%	2458
	21st to end	Night	12% 6% 2 4 3 4 3 3 5% 5% 54%	2076
March	1st to 10th	Night	10% 5% 1 5% 3 3 4 3 5% 7% 53%	5336
	11th to 20th	Night	14% 5% 2 4 3 2 2 2 4 5% 57%	5090
	21st to end	Night	12% 5% 1 3 2 2 3 3 5% 7% 58%	5588
April	1st to 10th	Night	9% 4 1 5% 4 3 4 4 6% 7% 53%	2310
	11th to 20th	Night	13% 4 1 4 4 4 4 3 5% 7% 50%	2093
	21st to end	Night	14% 6% 2 6% 3 3 3 3 4 5% 50%	2100
May	1st to 10th	Night	18% 6% 2 5% 3 3 3 3 5% 6% 45%	4239
	11th to 20th	Night	9% 3 1 4 3 3 4 3 6% 8% 54%	4143
	21st to end	Night	9% 4 2 5% 3 4 5% 4 7% 10% 47%	4542
June	1st to 10th	Night	3 2 1 3 3 3 3 4 6% 10% 64%	1800
	11th to 20th	Night	3 2 1 3 2 3 4 4 7% 8% 64%	1800
	21st to end	Night	3 3 2 4 4 4 4 5% 6% 12% 54%	1800
July	1st to 10th	Night	7% 5% 2 6% 5% 4 5% 4 6% 9% 46%	4078
	11th to 20th	Night	3 3 2 5% 4 4 4 4 7% 10% 54%	4077
	21st to end	Night	4 3 1 4 4 4 5% 4 6% 9% 56%	4758
August	1st to 10th	Night	1 1 2 1 2 2 2 4 7% 78%	3255
	11th to 20th	Night	2 2 1 3 3 3 4 4 6% 11% 62%	3213
	21st to end	Night	4 3 1 4 4 4 4 4 6% 10% 57%	3618
September	1st to 10th	Night	8% 5% 2 6% 5% 4 4 5% 6% 9% 45%	2200
	11th to 20th	Night	9% 6% 2 6% 5% 4 5% 3 6% 9% 45%	2200
	21st to end	Night	9% 3 2 4 4 3 4 4 5% 9% 54%	2200
October	1st to 10th	Night	5% 3 1 3 3 3 3 3 5% 7% 63%	2200
	11th to 20th	Night	11% 5% 2 4 2 2 2 3 5% 5% 60%	2200
	21st to end	Night	9% 3 1 3 3 2 2 2 3 4 68%	2590
November	1st to 10th	Night	11% 5% 1 4 3 3 2 3 4 5% 58%	2492
	11th to 20th	Night	10% 5% 2 5% 3 3 3 3 4 5% 58%	2730
	21st to end	Night	15% 4 1 5% 4 3 3 3 4 6% 51%	2730
December	1st to 10th	Night	32% 7% 2 4 3 3 3 3 3 4 37%	4380
	11th to 20th	Night	16% 7% 2 6% 3 3 3 2 3 5% 50%	4946
	21st to end	Night	10% 4 1 4 3 3 3 3 4 7% 59%	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	31% 3 6% 21% 25% 14%	5290
	11th to 20th	Day	32% 2 3 14% 26% 22%	5772
	21st to end	Day	41% 3 7% 15% 24% 10%	6468
February	1st to 10th	Day	39% 4 6% 13% 18% 20%	2100
	11th to 20th	Day	36% 4 7% 19% 19% 15%	2059
	21st to end	Day	32% 5% 8% 16% 23% 17%	1730
March	1st to 10th	Day	32% 4 8% 16% 15% 25%	4748
	11th to 20th	Day	33% 4 5% 8% 15% 36%	5090
	21st to end	Day	33% 4 8% 20% 20% 15%	5585
April	1st to 10th	Day	35% 6% 9% 17% 18% 16%	2310
	11th to 20th	Day	35% 6% 9% 18% 16% 17%	2472
	21st to end	Day	36% 5% 10% 17% 18% 14%	2520
May	1st to 10th	Day	41% 6% 9% 20% 16% 8%	5931
	11th to 20th	Day	27% 6% 13% 22% 19% 12%	5996
	21st to end	Day	34% 7% 10% 30% 17% 2	6590
June	1st to 10th	Day	21% 7% 15% 29% 23% 5%	2601
	11th to 20th	Day	24% 6% 11% 27% 23% 8%	2600
	21st to end	Day	30% 8% 16% 25% 16% 4	2600
July	1st to 10th	Day	40% 6% 15% 30% 9% 1	5836
	11th to 20th	Day	28% 8% 17% 32% 13% 2	5831
	21st to end	Day	25% 9% 16% 29% 19% 2	5935
August	1st to 10th	Day	9% 4 11% 41% 33% 2	3892
	11th to 20th	Day	15% 6% 22% 42% 14% 2	3882
	21st to end	Day	23% 8% 18% 27% 22% 2	4288
September	1st to 10th	Day	38% 7% 13% 19% 16% 6%	2200
	11th to 20th	Day	36% 8% 13% 21% 17% 4	2200
	21st to end	Day	29% 6% 11% 25% 16% 13%	2200
October	1st to 10th	Day	16% 4 7% 14% 22% 37%	3590
	11th to 20th	Day	32% 5% 6% 15% 18% 24%	3568
	21st to end	Day	22% 5% 7% 15% 35% 17%	3578
November	1st to 10th	Day	37% 4 7% 17% 21% 14%	2021
	11th to 20th	Day	33% 3 8% 18% 21% 17%	1890
	21st to end	Day	41% 4 6% 19% 17% 15%	1890
December	1st to 10th	Day	56% 3 6% 11% 16% 8%	3030
	11th to 20th	Day	42% 7% 7% 13% 15% 16%	3479
	21st to end	Day	30% 4 5% 17% 28% 17%	4587
January	1st to 10th	Night	28% 3 8% 18% 24% 18%	7635
	11th to 20th	Night	29% 2 4 15% 25% 25%	7260
	21st to end	Night	43% 3 5% 14% 22% 13%	7746
February	1st to 10th	Night	30% 5% 7% 17% 18% 24%	2520
	11th to 20th	Night	34% 3 8% 19% 19% 17%	2458
	21st to end	Night	32% 4 7% 17% 22% 18%	2076
March	1st to 10th	Night	31% 5% 10% 20% 13% 20%	5336
	11th to 20th	Night	31% 4 7% 11% 16% 31%	5090
	21st to end	Night	26% 5% 10% 23% 20% 15%	5588
April	1st to 10th	Night	28% 6% 12% 20% 16% 17%	2310
	11th to 20th	Night	33% 6% 12% 16% 15% 18%	2093
	21st to end	Night	36% 6% 11% 17% 17% 13%	2100
May	1st to 10th	Night	38% 5% 11% 19% 17% 10%	4265
	11th to 20th	Night	27% 6% 12% 19% 20% 16%	4144
	21st to end	Night	30% 7% 15% 29% 16% 2	4551
June	1st to 10th	Night	17% 6% 17% 34% 24% 3	1800
	11th to 20th	Night	17% 6% 13% 29% 27% 7%	1800
	21st to end	Night	23% 8% 20% 29% 17% 4	1800
July	1st to 10th	Night	34% 8% 21% 29% 7% 1	4035
	11th to 20th	Night	23% 8% 23% 32% 13% 1	4026
	21st to end	Night	23% 8% 20% 30% 18% 1	4620
August	1st to 10th	Night	8% 5% 11% 45% 29% 2	3244
	11th to 20th	Night	15% 7% 28% 38% 11% 2	3243
	21st to end	Night	22% 9% 22% 29% 17% 2	3618
September	1st to 10th	Night	34% 9% 17% 18% 16% 7%	2200
	11th to 20th	Night	34% 8% 17% 20% 17% 4	2200
	21st to end	Night	26% 5% 14% 24% 17% 13%	2200
October	1st to 10th	Night	16% 5% 7% 17% 19% 36%	3590
	11th to 20th	Night	23% 5% 9% 16% 19% 27%	3570
	21st to end	Night	17% 3 8% 16% 37% 19%	4178
November	1st to 10th	Night	28% 5% 7% 19% 25% 16%	2492
	11th to 20th	Night	29% 4 10% 18% 21% 18%	2730
	21st to end	Night	35% 4 8% 19% 18% 16%	2730
December	1st to 10th	Night	52% 3 7% 12% 13% 12%	4380
	11th to 20th	Night	37% 4 8% 16% 18% 16%	4947
	21st to end	Night	26% 5% 8% 17% 25% 20%	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	21% 5% 23% 32% 18% 2	330
	11th to 20th	Day	17% 6% 22% 37% 15% 2	330
	21st to end	Day	20% 7% 26% 33% 12% 1	363
February	1st to 10th	Day	18% 8% 23% 25% 20% 6%	330
	11th to 20th	Day	17% 6% 34% 29% 13% 2	330
	21st to end	Day	19% 7% 27% 34% 12%	273
March	1st to 10th	Day	21% 8% 29% 31% 10%	330
	11th to 20th	Day	11% 7% 32% 35% 15% 1	330
	21st to end	Day	15% 6% 29% 34% 14% 1	363
April	1st to 10th	Day	16% 8% 32% 32% 12%	330
	11th to 20th	Day	10% 8% 37% 35% 9%	510
	21st to end	Day	11% 7% 36% 35% 10%	540
May	1st to 10th	Day	15% 5% 31% 37% 11% 1	706
	11th to 20th	Day	15% 5% 29% 36% 13% 2	775
	21st to end	Day	11% 4 23% 45% 17% 1	844
June	1st to 10th	Day	6% 1 11% 49% 28% 5%	731
	11th to 20th	Day	5% 1 11% 50% 29% 5%	730
	21st to end	Day	5% 1 8% 39% 38% 9%	730
July	1st to 10th	Day	9% 2 5% 34% 40% 10%	721
	11th to 20th	Day	4 1 3 35% 47% 9%	718
	21st to end	Day	4 4 32% 43% 16%	659
August	1st to 10th	Day	1 1 2 28% 50% 19%	527
	11th to 20th	Day	4 1 2 27% 45% 22%	517
	21st to end	Day	5% 1 2 25% 36% 29%	573
September	1st to 10th	Day	9% 2 3 15% 46% 26%	330
	11th to 20th	Day	5% 2 17% 37% 38%	330
	21st to end	Day	9% 1 2 13% 49% 25%	330
October	1st to 10th	Day	8% 2 5% 25% 39% 22%	330
	11th to 20th	Day	11% 3 5% 34% 39% 9%	330
	21st to end	Day	13% 6% 17% 32% 26% 6%	363
November	1st to 10th	Day	17% 4 16% 28% 25% 9%	330
	11th to 20th	Day	19% 5% 14% 28% 26% 8%	330
	21st to end	Day	23% 3 22% 31% 16% 5%	330
December	1st to 10th	Day	20% 6% 20% 27% 20% 7%	330
	11th to 20th	Day	21% 7% 18% 25% 26% 3	330
	21st to end	Day	13% 5% 19% 35% 24% 4	363
January	1st to 10th	Night	18% 4 21% 43% 15% 1	1050
	11th to 20th	Night	17% 5% 23% 46% 8% 1	903
	21st to end	Night	20% 5% 23% 44% 8%	924
February	1st to 10th	Night	15% 6% 25% 43% 11% 1	840
	11th to 20th	Night	19% 6% 31% 37% 7%	824
	21st to end	Night	15% 7% 35% 39% 4	692
March	1st to 10th	Night	16% 7% 35% 37% 4	773
	11th to 20th	Night	12% 8% 35% 40% 5%	630
	21st to end	Night	11% 7% 43% 35% 4	693
April	1st to 10th	Night	8% 7% 45% 36% 3	630
	11th to 20th	Night	14% 5% 45% 33% 3	623
	21st to end	Night	13% 9% 42% 30% 4	630
May	1st to 10th	Night	11% 5% 48% 33% 3	630
	11th to 20th	Night	12% 5% 39% 37% 7%	621
	21st to end	Night	7% 3 38% 45% 6%	683
June	1st to 10th	Night	2 2 25% 58% 14%	600
	11th to 20th	Night	3 1 30% 57% 9%	600
	21st to end	Night	3 1 18% 60% 19%	600
July	1st to 10th	Night	7% 3 12% 59% 19%	585
	11th to 20th	Night	3 1 12% 63% 21% 1	582
	21st to end	Night	4 1 10% 60% 24% 1	657
August	1st to 10th	Night	1 10% 61% 25% 1	597
	11th to 20th	Night	4 1 10% 59% 25% 2	594
	21st to end	Night	5% 1 5% 52% 33% 4	660
September	1st to 10th	Night	8% 2 6% 48% 32% 4	600
	11th to 20th	Night	9% 1 8% 42% 38% 3	600
	21st to end	Night	10% 1 9% 46% 30% 4	600
October	1st to 10th	Night	6% 1 9% 50% 33% 2	600
	11th to 20th	Night	12% 2 13% 45% 27% 1	600
	21st to end	Night	9% 4 20% 44% 22% 2	830
November	1st to 10th	Night	13% 3 16% 41% 26% 2	852
	11th to 20th	Night	12% 4 15% 45% 23% 1	1050
	21st to end	Night	17% 4 19% 42% 18% 1	1050
December	1st to 10th	Night	20% 3 16% 43% 18% 1	1050
	11th to 20th	Night	20% 5% 19% 42% 14%	1050
	21st to end	Night	15% 4 19% 47% 14% 1	1155

Page generated at 2026-05-29 00:53:24. Version ac07

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