Observatorio Bahía Bacochibampo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatorio Bahía Bacochibampo clear sky chart from 2005-11-06 to 2026-05-17.

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
Transparency	Day	13% 3 8% 15% 25% 36%	135667
	Night	15% 3 6% 12% 24% 40%	135716
Seeing	Day	3 1 10% 30% 41% 14%	17118
	Night	4 1 9% 33% 40% 14%	27323

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	11% 1 5% 17% 34% 32%	5321
	11th to 20th	Day	13% 2 3 6% 24% 53%	5340
	21st to end	Day	24% 3 4 12% 25% 32%	5858
February	1st to 10th	Day	17% 3 5% 7% 27% 41%	2100
	11th to 20th	Day	22% 2 5% 9% 25% 36%	2079
	21st to end	Day	15% 3 3 10% 27% 42%	1903
March	1st to 10th	Day	17% 2 4 7% 28% 41%	5064
	11th to 20th	Day	12% 2 3 12% 29% 42%	5110
	21st to end	Day	14% 2 3 6% 28% 47%	5607
April	1st to 10th	Day	14% 2 3 8% 24% 50%	2310
	11th to 20th	Day	12% 2 3 7% 24% 53%	2370
	21st to end	Day	9% 1 2 7% 23% 57%	2520
May	1st to 10th	Day	5% 1 1 4 25% 65%	5591
	11th to 20th	Day	9% 2 3 6% 22% 58%	5923
	21st to end	Day	5% 1 2 3 18% 71%	6424
June	1st to 10th	Day	8% 2 3 9% 31% 46%	2600
	11th to 20th	Day	8% 2 3 10% 36% 42%	2600
	21st to end	Day	12% 5% 9% 20% 33% 22%	2600
July	1st to 10th	Day	17% 8% 22% 23% 22% 7%	5816
	11th to 20th	Day	20% 9% 23% 31% 16% 1	5811
	21st to end	Day	17% 7% 23% 30% 13% 10%	6217
August	1st to 10th	Day	19% 8% 21% 32% 17% 3	4208
	11th to 20th	Day	15% 8% 23% 38% 14% 2	4016
	21st to end	Day	15% 7% 16% 34% 25% 4	3975
September	1st to 10th	Day	26% 8% 16% 23% 20% 7%	2200
	11th to 20th	Day	12% 4 7% 25% 31% 21%	2200
	21st to end	Day	9% 4 7% 20% 33% 26%	2200
October	1st to 10th	Day	5% 2 4 13% 30% 46%	3511
	11th to 20th	Day	9% 1 3 14% 38% 36%	3250
	21st to end	Day	5% 1 2 8% 23% 62%	3548
November	1st to 10th	Day	9% 2 3 10% 26% 50%	2059
	11th to 20th	Day	13% 2 3 11% 26% 45%	2100
	21st to end	Day	20% 3 5% 15% 28% 30%	2089
December	1st to 10th	Day	15% 2 4 9% 16% 54%	3040
	11th to 20th	Day	18% 2 3 6% 23% 48%	3498
	21st to end	Day	10% 1 4 12% 35% 38%	4609
January	1st to 10th	Night	13% 2 4 14% 34% 33%	7605
	11th to 20th	Night	14% 1 2 5% 23% 56%	7650
	21st to end	Night	28% 3 4 11% 25% 29%	8353
February	1st to 10th	Night	20% 2 3 8% 22% 45%	2520
	11th to 20th	Night	22% 3 4 10% 25% 36%	2438
	21st to end	Night	17% 2 4 7% 28% 42%	1903
March	1st to 10th	Night	21% 2 3 5% 24% 44%	5050
	11th to 20th	Night	11% 3 4 10% 27% 45%	5110
	21st to end	Night	14% 2 3 6% 22% 52%	5610
April	1st to 10th	Night	12% 2 2 8% 22% 53%	2310
	11th to 20th	Night	13% 2 2 6% 24% 53%	2198
	21st to end	Night	9% 1 2 5% 20% 62%	2100
May	1st to 10th	Night	5% 1 3 23% 68%	4600
	11th to 20th	Night	9% 2 3 5% 21% 60%	4129
	21st to end	Night	7% 1 1 2 16% 72%	4474
June	1st to 10th	Night	8% 2 3 7% 25% 55%	1800
	11th to 20th	Night	9% 2 3 7% 29% 51%	1800
	21st to end	Night	15% 5% 9% 17% 26% 28%	1800
July	1st to 10th	Night	23% 9% 18% 21% 19% 10%	4055
	11th to 20th	Night	25% 8% 17% 33% 16% 1	4046
	21st to end	Night	22% 8% 20% 26% 12% 12%	4344
August	1st to 10th	Night	26% 12% 20% 25% 14% 4	2928
	11th to 20th	Night	23% 8% 18% 33% 16% 2	3109
	21st to end	Night	17% 7% 16% 33% 22% 5%	3924
September	1st to 10th	Night	30% 9% 14% 21% 20% 6%	2200
	11th to 20th	Night	12% 3 9% 21% 31% 23%	2200
	21st to end	Night	10% 4 7% 21% 28% 31%	2200
October	1st to 10th	Night	6% 2 4 10% 28% 50%	3683
	11th to 20th	Night	9% 2 2 10% 34% 43%	3898
	21st to end	Night	4 1 2 7% 20% 66%	4252
November	1st to 10th	Night	10% 2 3 8% 26% 50%	2460
	11th to 20th	Night	15% 2 3 8% 26% 46%	2520
	21st to end	Night	21% 3 5% 12% 27% 32%	2525
December	1st to 10th	Night	15% 2 4 8% 19% 51%	4370
	11th to 20th	Night	14% 2 3 7% 22% 52%	4941
	21st to end	Night	12% 3 4 9% 35% 39%	6611

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	3 1 14% 41% 33% 8%	330
	11th to 20th	Day	4 2 8% 40% 35% 12%	330
	21st to end	Day	5% 2 19% 40% 27% 7%	364
February	1st to 10th	Day	5% 3 20% 36% 30% 6%	540
	11th to 20th	Day	9% 2 25% 36% 24% 5%	535
	21st to end	Day	5% 3 29% 39% 18% 5%	446
March	1st to 10th	Day	5% 4 24% 38% 25% 4	540
	11th to 20th	Day	4 2 21% 36% 29% 8%	540
	21st to end	Day	4 3 20% 44% 25% 5%	594
April	1st to 10th	Day	3 2 23% 39% 28% 6%	540
	11th to 20th	Day	2 2 18% 47% 24% 7%	532
	21st to end	Day	1 1 15% 38% 36% 8%	540
May	1st to 10th	Day	2 1 18% 37% 33% 9%	543
	11th to 20th	Day	1 1 14% 44% 33% 8%	553
	21st to end	Day	1 1 9% 36% 45% 9%	573
June	1st to 10th	Day	1 1 5% 30% 53% 10%	530
	11th to 20th	Day	2 1 3 26% 53% 15%	530
	21st to end	Day	3 1 2 23% 57% 15%	530
July	1st to 10th	Day	3 1 3 21% 56% 16%	526
	11th to 20th	Day	5% 1 1 16% 58% 20%	524
	21st to end	Day	3 2 2 15% 56% 22%	575
August	1st to 10th	Day	3 1 16% 53% 27%	527
	11th to 20th	Day	1 1 2 13% 56% 27%	517
	21st to end	Day	3 1 1 13% 52% 31%	583
September	1st to 10th	Day	6% 2 2 18% 48% 24%	530
	11th to 20th	Day	3 1 15% 60% 20%	530
	21st to end	Day	2 3 22% 52% 21%	530
October	1st to 10th	Day	3 4 24% 51% 18%	480
	11th to 20th	Day	6% 5% 25% 40% 24%	330
	21st to end	Day	2 5% 27% 45% 21%	363
November	1st to 10th	Day	3 1 6% 32% 36% 22%	330
	11th to 20th	Day	3 1 12% 28% 38% 17%	330
	21st to end	Day	6% 4 11% 35% 33% 12%	330
December	1st to 10th	Day	6% 1 8% 33% 43% 8%	330
	11th to 20th	Day	5% 1 8% 36% 36% 14%	330
	21st to end	Day	6% 2 10% 40% 31% 11%	363
January	1st to 10th	Night	3 1 14% 46% 33% 3	840
	11th to 20th	Night	3 1 13% 48% 31% 3	840
	21st to end	Night	7% 2 20% 46% 23% 2	924
February	1st to 10th	Night	5% 2 16% 41% 31% 5%	840
	11th to 20th	Night	6% 1 16% 49% 25% 3	824
	21st to end	Night	4 1 18% 55% 19% 3	692
March	1st to 10th	Night	7% 1 21% 45% 24% 2	840
	11th to 20th	Night	4 1 12% 41% 36% 6%	840
	21st to end	Night	4 1 12% 44% 34% 5%	924
April	1st to 10th	Night	2 1 12% 47% 32% 6%	840
	11th to 20th	Night	3 1 12% 46% 34% 4	744
	21st to end	Night	2 7% 44% 41% 6%	630
May	1st to 10th	Night	2 7% 44% 41% 5%	630
	11th to 20th	Night	1 4 36% 52% 7%	609
	21st to end	Night	3 32% 53% 11%	650
June	1st to 10th	Night	1 2 23% 61% 13%	600
	11th to 20th	Night	2 1 1 15% 62% 20%	600
	21st to end	Night	1 1 11% 53% 33%	600
July	1st to 10th	Night	2 1 2 11% 51% 33%	585
	11th to 20th	Night	3 2 9% 52% 33%	582
	21st to end	Night	4 2 12% 44% 37%	657
August	1st to 10th	Night	4 1 2 8% 42% 43%	597
	11th to 20th	Night	5% 1 2 8% 38% 48%	594
	21st to end	Night	3 1 3 9% 42% 42%	857
September	1st to 10th	Night	7% 2 3 11% 41% 35%	800
	11th to 20th	Night	4 2 6% 54% 34%	800
	21st to end	Night	3 2 16% 57% 22%	800
October	1st to 10th	Night	2 2 25% 55% 17%	800
	11th to 20th	Night	6% 4 28% 50% 11%	800
	21st to end	Night	2 1 5% 31% 51% 11%	880
November	1st to 10th	Night	2 6% 37% 44% 11%	820
	11th to 20th	Night	4 1 10% 39% 38% 9%	840
	21st to end	Night	5% 2 13% 42% 32% 6%	840
December	1st to 10th	Night	5% 1 11% 46% 33% 4	840
	11th to 20th	Night	4 1 13% 48% 29% 5%	840
	21st to end	Night	5% 1 15% 46% 25% 6%	924

Page generated at 2026-05-13 22:58:56. Version ac07

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