Ciudad Delicias
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ciudad Delicias clear sky chart from 2005-11-06 to 2026-01-17.

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	3 2 1 3 3 3 3 3 5% 8% 66%	127239
	Night	5% 4 2 5% 4 4 4 4 5% 7% 56%	124869
Transparency	Day	17% 4 8% 17% 25% 29%	130961
	Night	26% 4 6% 13% 23% 27%	129243
Seeing	Day	5% 5% 16% 29% 29% 16%	15663
	Night	7% 3 19% 43% 25% 2	25560

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	3 3 1 2 2 2 2 2 4 7% 74%	4637
	11th to 20th	Day	2 2 1 2 2 2 3 3 4 5% 75%	4600
	21st to end	Day	3 3 2 4 3 2 3 3 4 8% 65%	4994
February	1st to 10th	Day	4 3 1 4 3 3 3 3 3 5% 67%	2000
	11th to 20th	Day	4 4 1 3 2 3 3 4 5% 5% 67%	1949
	21st to end	Day	2 2 2 2 2 3 4 6% 7% 68%	1650
March	1st to 10th	Day	2 3 1 3 2 3 3 3 5% 7% 66%	4856
	11th to 20th	Day	2 2 1 2 2 2 3 3 4 5% 74%	5000
	21st to end	Day	1 2 1 3 2 3 3 3 6% 7% 68%	5689
April	1st to 10th	Day	3 2 1 2 3 4 3 3 5% 7% 67%	2400
	11th to 20th	Day	2 2 1 2 2 3 3 3 5% 5% 73%	2374
	21st to end	Day	3 2 1 3 2 2 2 2 4 6% 73%	2400
May	1st to 10th	Day	1 1 1 1 1 1 2 2 2 4 84%	5405
	11th to 20th	Day	3 4 2 5% 3 3 3 3 4 6% 65%	5405
	21st to end	Day	2 1 1 2 2 2 2 2 3 5% 78%	5933
June	1st to 10th	Day	1 1 1 2 2 2 3 3 5% 9% 71%	2400
	11th to 20th	Day	1 2 1 2 3 3 4 4 5% 8% 68%	2400
	21st to end	Day	3 2 2 4 4 3 4 5% 7% 10% 55%	2400
July	1st to 10th	Day	3 3 1 4 4 4 5% 4 8% 11% 52%	5440
	11th to 20th	Day	3 2 1 4 3 5% 5% 5% 8% 13% 51%	5440
	21st to end	Day	2 2 1 3 3 4 5% 5% 8% 13% 54%	5920
August	1st to 10th	Day	1 2 1 3 3 3 4 5% 8% 11% 60%	3905
	11th to 20th	Day	3 2 1 3 3 4 5% 5% 8% 11% 54%	3846
	21st to end	Day	3 2 1 4 4 4 5% 4 7% 11% 54%	4312
September	1st to 10th	Day	6% 5% 2 7% 5% 6% 6% 5% 7% 10% 41%	2400
	11th to 20th	Day	7% 5% 2 6% 4 4 4 5% 7% 8% 48%	2372
	21st to end	Day	6% 4 1 4 4 4 4 3 5% 7% 59%	2200
October	1st to 10th	Day	3 2 1 3 3 3 3 3 7% 7% 65%	2105
	11th to 20th	Day	4 3 1 3 2 3 3 2 4 7% 69%	2000
	21st to end	Day	4 3 1 2 1 1 1 2 2 4 79%	2200
November	1st to 10th	Day	3 3 1 2 2 2 2 2 3 4 76%	2059
	11th to 20th	Day	4 3 1 3 2 2 3 2 4 4 72%	2100
	21st to end	Day	5% 3 1 4 4 3 3 3 5% 6% 62%	2100
December	1st to 10th	Day	5% 4 2 5% 3 4 4 4 7% 7% 56%	3370
	11th to 20th	Day	2 3 1 3 2 2 3 3 5% 7% 69%	3874
	21st to end	Day	1 1 1 2 1 2 2 3 4 7% 75%	5104
January	1st to 10th	Night	3 2 1 2 2 1 2 2 3 6% 76%	5548
	11th to 20th	Night	2 2 1 2 2 2 3 3 4 8% 72%	5512
	21st to end	Night	5% 5% 2 5% 3 3 3 3 5% 7% 59%	5984
February	1st to 10th	Night	5% 3 1 3 3 3 2 3 5% 6% 67%	2400
	11th to 20th	Night	4 5% 1 3 3 3 2 3 5% 6% 63%	2338
	21st to end	Night	4 4 1 3 3 3 4 3 4 7% 64%	1980
March	1st to 10th	Night	4 4 1 3 2 2 3 3 5% 6% 66%	5029
	11th to 20th	Night	3 3 1 3 2 2 3 3 4 6% 70%	5000
	21st to end	Night	4 5% 1 3 3 3 3 2 4 5% 68%	5271
April	1st to 10th	Night	4 4 2 3 3 2 3 3 5% 6% 66%	2000
	11th to 20th	Night	5% 4 2 4 2 2 4 3 4 6% 64%	1977
	21st to end	Night	5% 4 1 3 2 3 3 3 5% 5% 66%	2000
May	1st to 10th	Night	2 2 1 2 1 2 2 2 3 6% 79%	4510
	11th to 20th	Night	6% 5% 2 6% 4 4 4 3 5% 6% 58%	4510
	21st to end	Night	3 3 2 4 3 3 4 3 5% 6% 64%	4944
June	1st to 10th	Night	4 3 2 6% 5% 6% 7% 6% 7% 7% 47%	2000
	11th to 20th	Night	3 4 2 8% 7% 6% 7% 6% 8% 10% 40%	2000
	21st to end	Night	7% 7% 3 9% 7% 6% 7% 6% 7% 10% 32%	2000
July	1st to 10th	Night	9% 8% 4 11% 7% 7% 7% 5% 7% 9% 26%	4538
	11th to 20th	Night	4 6% 3 11% 9% 7% 8% 6% 8% 10% 28%	4537
	21st to end	Night	6% 7% 4 11% 8% 8% 8% 6% 7% 8% 27%	4951
August	1st to 10th	Night	5% 6% 3 10% 8% 8% 8% 7% 10% 9% 27%	3255
	11th to 20th	Night	5% 7% 3 11% 9% 8% 8% 7% 9% 10% 23%	3213
	21st to end	Night	5% 6% 3 9% 7% 7% 7% 7% 9% 12% 28%	3597
September	1st to 10th	Night	10% 8% 4 9% 8% 8% 8% 6% 8% 9% 23%	2000
	11th to 20th	Night	12% 8% 3 8% 6% 6% 5% 5% 7% 9% 29%	2025
	21st to end	Night	8% 5% 3 9% 6% 6% 7% 5% 7% 8% 35%	2200
October	1st to 10th	Night	5% 4 2 5% 4 5% 5% 3 6% 6% 55%	2288
	11th to 20th	Night	8% 4 2 5% 3 4 4 3 5% 7% 55%	2400
	21st to end	Night	4 2 1 3 3 2 2 2 3 5% 73%	2640
November	1st to 10th	Night	5% 1 2 1 2 2 1 3 5% 78%	2460
	11th to 20th	Night	5% 2 1 4 3 2 3 2 4 5% 69%	2520
	21st to end	Night	5% 4 1 3 3 3 3 2 5% 5% 66%	2520
December	1st to 10th	Night	3 5% 2 5% 4 4 4 3 5% 7% 59%	4040
	11th to 20th	Night	2 3 1 2 2 2 3 2 4 7% 74%	4566
	21st to end	Night	3 2 1 3 2 2 3 2 4 6% 72%	6116

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	13% 2 3 17% 37% 28%	4638
	11th to 20th	Day	15% 2 2 16% 32% 33%	4600
	21st to end	Day	21% 2 5% 19% 32% 22%	4994
February	1st to 10th	Day	21% 2 4 10% 27% 35%	2000
	11th to 20th	Day	19% 3 4 13% 29% 32%	1959
	21st to end	Day	14% 4 2 13% 33% 34%	1650
March	1st to 10th	Day	18% 2 2 10% 23% 45%	4856
	11th to 20th	Day	13% 3 3 8% 19% 55%	5000
	21st to end	Day	12% 4 2 10% 28% 44%	5691
April	1st to 10th	Day	17% 3 3 9% 23% 46%	2400
	11th to 20th	Day	13% 3 2 10% 23% 49%	2374
	21st to end	Day	15% 2 1 7% 25% 50%	2400
May	1st to 10th	Day	8% 1 1 5% 16% 69%	5440
	11th to 20th	Day	21% 2 4 7% 23% 43%	5408
	21st to end	Day	11% 2 3 10% 19% 55%	5945
June	1st to 10th	Day	11% 3 4 19% 32% 31%	2400
	11th to 20th	Day	14% 3 4 15% 32% 32%	2400
	21st to end	Day	22% 5% 10% 23% 23% 15%	2400
July	1st to 10th	Day	24% 8% 20% 25% 18% 6%	5381
	11th to 20th	Day	23% 7% 21% 34% 12% 3	5377
	21st to end	Day	19% 8% 22% 28% 19% 5%	5752
August	1st to 10th	Day	15% 6% 17% 37% 22% 2	3892
	11th to 20th	Day	22% 7% 21% 32% 16% 2	3882
	21st to end	Day	23% 7% 17% 32% 19% 3	4311
September	1st to 10th	Day	36% 9% 16% 20% 11% 8%	2400
	11th to 20th	Day	31% 6% 13% 18% 21% 10%	2372
	21st to end	Day	24% 5% 10% 23% 24% 14%	2200
October	1st to 10th	Day	12% 2 7% 14% 28% 38%	3435
	11th to 20th	Day	12% 2 7% 20% 27% 33%	3250
	21st to end	Day	8% 1 1 11% 43% 35%	3548
November	1st to 10th	Day	14% 2 5% 17% 36% 27%	2059
	11th to 20th	Day	18% 2 5% 19% 31% 24%	2100
	21st to end	Day	22% 3 6% 22% 24% 23%	2100
December	1st to 10th	Day	27% 2 5% 20% 28% 18%	3370
	11th to 20th	Day	16% 3 4 21% 36% 19%	3873
	21st to end	Day	11% 2 3 13% 40% 30%	5104
January	1st to 10th	Night	13% 1 3 13% 41% 29%	5548
	11th to 20th	Night	14% 2 4 13% 31% 36%	5512
	21st to end	Night	25% 3 4 15% 31% 23%	5984
February	1st to 10th	Night	19% 3 3 12% 26% 37%	2400
	11th to 20th	Night	23% 3 3 12% 25% 33%	2338
	21st to end	Night	20% 3 2 10% 29% 36%	1980
March	1st to 10th	Night	20% 2 2 8% 26% 43%	5029
	11th to 20th	Night	15% 3 4 6% 21% 51%	5000
	21st to end	Night	20% 3 2 8% 25% 42%	5271
April	1st to 10th	Night	20% 3 3 9% 25% 41%	2000
	11th to 20th	Night	21% 3 4 8% 23% 41%	1977
	21st to end	Night	20% 3 4 8% 21% 45%	2000
May	1st to 10th	Night	10% 2 1 7% 16% 63%	4537
	11th to 20th	Night	28% 3 3 8% 18% 40%	4511
	21st to end	Night	20% 4 4 11% 16% 45%	4954
June	1st to 10th	Night	30% 6% 9% 17% 19% 18%	2000
	11th to 20th	Night	35% 7% 7% 13% 20% 19%	2000
	21st to end	Night	44% 7% 10% 16% 12% 11%	2000
July	1st to 10th	Night	51% 8% 13% 14% 12% 2	4490
	11th to 20th	Night	47% 8% 17% 18% 8% 3	4480
	21st to end	Night	49% 8% 12% 13% 13% 5%	4808
August	1st to 10th	Night	44% 9% 13% 19% 13% 2	3244
	11th to 20th	Night	51% 8% 14% 18% 8% 1	3243
	21st to end	Night	42% 8% 14% 22% 12% 3	3597
September	1st to 10th	Night	52% 9% 14% 13% 8% 5%	2000
	11th to 20th	Night	49% 8% 11% 12% 12% 9%	2025
	21st to end	Night	41% 7% 10% 15% 14% 13%	2200
October	1st to 10th	Night	20% 4 7% 11% 19% 40%	3743
	11th to 20th	Night	22% 3 7% 17% 20% 31%	3898
	21st to end	Night	11% 2 2 13% 38% 33%	4252
November	1st to 10th	Night	12% 2 5% 16% 35% 30%	2460
	11th to 20th	Night	19% 2 7% 18% 27% 27%	2520
	21st to end	Night	21% 4 6% 18% 26% 25%	2520
December	1st to 10th	Night	27% 2 5% 22% 26% 18%	4040
	11th to 20th	Night	14% 2 4 18% 40% 22%	4566
	21st to end	Night	15% 2 3 11% 40% 29%	6116

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	7% 4 25% 37% 20% 7%	330
	11th to 20th	Day	5% 3 20% 45% 23% 3	318
	21st to end	Day	6% 5% 30% 38% 16% 4	330
February	1st to 10th	Day	10% 5% 21% 31% 22% 11%	300
	11th to 20th	Day	11% 6% 28% 33% 20% 2	300
	21st to end	Day	6% 7% 32% 33% 18% 3	249
March	1st to 10th	Day	8% 12% 33% 28% 18% 2	450
	11th to 20th	Day	9% 12% 26% 34% 16% 3	500
	21st to end	Day	9% 13% 29% 33% 15% 2	550
April	1st to 10th	Day	6% 13% 27% 32% 17% 4	500
	11th to 20th	Day	4 12% 36% 28% 16% 3	492
	21st to end	Day	5% 12% 29% 33% 18% 3	500
May	1st to 10th	Day	5% 8% 29% 35% 19% 4	503
	11th to 20th	Day	4 6% 25% 38% 22% 5%	528
	21st to end	Day	3 3 22% 41% 23% 7%	573
June	1st to 10th	Day	3 2 11% 35% 34% 15%	530
	11th to 20th	Day	2 1 7% 31% 41% 17%	530
	21st to end	Day	5% 1 3 28% 36% 27%	530
July	1st to 10th	Day	5% 2 3 22% 38% 30%	526
	11th to 20th	Day	3 1 2 23% 42% 28%	524
	21st to end	Day	2 1 3 20% 41% 33%	575
August	1st to 10th	Day	1 1 2 15% 43% 37%	527
	11th to 20th	Day	5% 2 3 17% 36% 38%	517
	21st to end	Day	5% 1 2 18% 37% 37%	583
September	1st to 10th	Day	6% 2 4 20% 38% 30%	530
	11th to 20th	Day	7% 1 3 18% 41% 30%	502
	21st to end	Day	6% 1 4 15% 40% 34%	330
October	1st to 10th	Day	6% 2 6% 21% 36% 29%	330
	11th to 20th	Day	6% 3 9% 21% 40% 22%	330
	21st to end	Day	7% 2 15% 22% 36% 18%	363
November	1st to 10th	Day	2 2 13% 32% 35% 15%	330
	11th to 20th	Day	6% 2 14% 29% 36% 14%	330
	21st to end	Day	11% 5% 17% 36% 25% 7%	330
December	1st to 10th	Day	8% 3 15% 36% 31% 7%	330
	11th to 20th	Day	4 2 24% 37% 24% 9%	330
	21st to end	Day	4 4 23% 35% 25% 9%	363
January	1st to 10th	Night	7% 3 19% 51% 19% 1	840
	11th to 20th	Night	6% 2 18% 54% 19%	824
	21st to end	Night	6% 5% 27% 49% 13% 1	880
February	1st to 10th	Night	6% 4 24% 46% 20% 1	800
	11th to 20th	Night	7% 5% 28% 49% 11%	784
	21st to end	Night	5% 6% 32% 48% 9%	660
March	1st to 10th	Night	8% 7% 34% 43% 8% 1	800
	11th to 20th	Night	9% 6% 29% 44% 11%	800
	21st to end	Night	7% 8% 32% 45% 9%	791
April	1st to 10th	Night	6% 8% 38% 39% 8%	600
	11th to 20th	Night	7% 8% 37% 42% 6%	593
	21st to end	Night	7% 7% 39% 41% 6%	600
May	1st to 10th	Night	7% 8% 39% 38% 8%	600
	11th to 20th	Night	5% 4 37% 43% 10%	591
	21st to end	Night	4 5% 29% 48% 13%	650
June	1st to 10th	Night	6% 3 18% 50% 23% 2	600
	11th to 20th	Night	5% 2 15% 47% 30% 1	600
	21st to end	Night	10% 3 9% 42% 33% 3	600
July	1st to 10th	Night	10% 2 6% 37% 40% 6%	585
	11th to 20th	Night	5% 3 5% 39% 44% 4	582
	21st to end	Night	8% 2 5% 33% 46% 7%	657
August	1st to 10th	Night	8% 3 2 31% 46% 10%	597
	11th to 20th	Night	8% 2 4 28% 45% 11%	594
	21st to end	Night	8% 3 3 28% 50% 7%	660
September	1st to 10th	Night	13% 2 3 29% 48% 6%	600
	11th to 20th	Night	17% 2 3 27% 48% 5%	600
	21st to end	Night	10% 2 6% 36% 43% 3	600
October	1st to 10th	Night	6% 1 9% 42% 39% 3	688
	11th to 20th	Night	9% 1 11% 41% 35% 2	800
	21st to end	Night	6% 3 9% 47% 33% 3	880
November	1st to 10th	Night	6% 14% 42% 36% 3	820
	11th to 20th	Night	6% 2 13% 49% 30% 2	840
	21st to end	Night	7% 2 20% 47% 23% 1	840
December	1st to 10th	Night	5% 2 15% 51% 25% 1	840
	11th to 20th	Night	5% 1 17% 52% 23% 2	840
	21st to end	Night	6% 2 21% 48% 21% 2	924

Page generated at 2026-01-13 23:14:29. Version ac07

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