Gila Sky 22
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gila Sky 22 clear sky chart from 2005-11-06 to 2026-02-01.

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	3 4 1 4 4 4 5% 4 6% 7% 60%	135692
	Night	2 3 1 4 3 3 4 3 5% 8% 64%	133807
Transparency	Day	21% 5% 8% 14% 27% 24%	130665
	Night	18% 5% 8% 16% 31% 22%	129837
Seeing	Day	10% 13% 27% 27% 17% 6%	15994
	Night	5% 10% 26% 35% 21% 3	26237

By Month

Percentage Cloud Cover SW (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	1 5% 2 3 2 3 3 3 5% 6% 67%	4188
	11th to 20th	Day	1 2 1 3 2 2 2 3 4 6% 75%	4190
	21st to end	Day	3 5% 1 3 2 2 3 3 6% 7% 64%	4609
February	1st to 10th	Day	1 3 1 3 3 3 3 3 6% 7% 69%	1800
	11th to 20th	Day	2 3 2 3 3 3 4 3 4 6% 68%	1899
	21st to end	Day	3 3 1 3 2 2 3 3 5% 6% 70%	1740
March	1st to 10th	Day	1 4 2 4 3 3 3 3 4 6% 66%	4954
	11th to 20th	Day	3 8% 1 4 3 3 4 4 6% 7% 58%	5000
	21st to end	Day	1 6% 2 5% 4 4 4 3 5% 7% 61%	5486
April	1st to 10th	Day	1 3 1 3 3 3 3 3 4 7% 71%	2370
	11th to 20th	Day	2 4 1 4 3 2 3 3 4 6% 68%	2371
	21st to end	Day	2 3 1 3 2 3 3 3 5% 5% 71%	2400
May	1st to 10th	Day	1 2 1 3 3 3 4 3 6% 6% 67%	5440
	11th to 20th	Day	2 3 1 4 3 3 4 3 5% 5% 67%	5699
	21st to end	Day	2 2 1 2 2 3 3 3 4 5% 74%	6423
June	1st to 10th	Day	3 4 1 4 4 4 4 5% 5% 7% 60%	2600
	11th to 20th	Day	2 2 1 3 3 3 4 3 5% 6% 68%	2600
	21st to end	Day	6% 5% 2 6% 5% 6% 6% 5% 7% 7% 45%	2600
July	1st to 10th	Day	4 3 1 5% 5% 6% 7% 5% 8% 8% 47%	5879
	11th to 20th	Day	3 3 2 6% 6% 7% 8% 6% 8% 10% 41%	5880
	21st to end	Day	5% 5% 3 10% 8% 9% 8% 6% 8% 9% 29%	6401
August	1st to 10th	Day	3 4 2 6% 6% 7% 7% 6% 8% 9% 43%	5762
	11th to 20th	Day	3 3 2 6% 6% 6% 7% 6% 8% 9% 42%	5366
	21st to end	Day	4 4 2 7% 6% 7% 8% 6% 8% 10% 37%	5984
September	1st to 10th	Day	9% 5% 2 7% 5% 5% 4 5% 6% 8% 44%	2400
	11th to 20th	Day	6% 4 2 5% 4 4 5% 4 6% 6% 54%	2368
	21st to end	Day	4 3 1 4 3 4 4 3 5% 5% 64%	2118
October	1st to 10th	Day	3 3 1 3 3 3 3 3 4 5% 70%	3270
	11th to 20th	Day	3 3 2 4 3 3 4 3 4 5% 66%	3250
	21st to end	Day	2 1 1 1 1 1 1 1 2 4 85%	3548
November	1st to 10th	Day	2 2 1 3 1 2 2 3 5% 6% 74%	2059
	11th to 20th	Day	1 2 2 4 2 2 3 3 4 6% 72%	2100
	21st to end	Day	2 4 1 4 3 3 3 4 5% 6% 65%	2072
December	1st to 10th	Day	1 3 1 2 2 2 2 3 5% 6% 72%	2758
	11th to 20th	Day	2 3 1 4 4 3 3 2 3 6% 68%	3499
	21st to end	Day	2 1 2 2 2 4 3 5% 6% 71%	4609
January	1st to 10th	Night	1 5% 2 5% 3 3 3 3 4 6% 64%	5997
	11th to 20th	Night	1 1 2 1 1 2 2 3 6% 80%	6010
	21st to end	Night	2 4 2 4 3 3 4 3 5% 7% 64%	6611
February	1st to 10th	Night	1 2 1 3 2 3 4 3 5% 7% 70%	2600
	11th to 20th	Night	2 4 1 4 3 3 3 3 4 6% 68%	2386
	21st to end	Night	1 3 1 3 2 3 3 3 4 5% 72%	1887
March	1st to 10th	Night	1 3 1 3 2 2 3 3 5% 6% 72%	4940
	11th to 20th	Night	2 6% 1 3 2 2 2 2 4 6% 68%	5000
	21st to end	Night	1 2 1 3 2 2 3 4 5% 7% 71%	5489
April	1st to 10th	Night	1 2 1 2 3 2 3 3 4 7% 71%	2030
	11th to 20th	Night	2 3 1 3 2 2 3 3 4 5% 72%	1977
	21st to end	Night	1 1 1 3 2 2 2 3 4 5% 75%	2000
May	1st to 10th	Night	2 1 1 3 2 2 3 3 4 6% 73%	4540
	11th to 20th	Night	1 2 1 2 2 3 3 3 4 5% 75%	4211
	21st to end	Night	1 2 2 1 2 2 2 3 5% 78%	4474
June	1st to 10th	Night	3 3 1 4 3 3 4 3 6% 8% 62%	1800
	11th to 20th	Night	3 2 1 3 3 3 2 3 4 6% 71%	1800
	21st to end	Night	6% 4 2 5% 5% 4 5% 5% 8% 9% 48%	1800
July	1st to 10th	Night	3 4 2 5% 4 5% 5% 5% 8% 10% 50%	4100
	11th to 20th	Night	2 3 2 6% 5% 5% 6% 5% 10% 13% 43%	4100
	21st to end	Night	3 5% 3 7% 6% 7% 7% 6% 9% 12% 35%	4472
August	1st to 10th	Night	2 3 1 6% 5% 6% 7% 6% 10% 13% 41%	4050
	11th to 20th	Night	2 3 1 6% 5% 5% 7% 7% 11% 14% 38%	4483
	21st to end	Night	4 5% 2 7% 5% 6% 8% 6% 10% 13% 33%	4993
September	1st to 10th	Night	5% 4 2 6% 5% 5% 6% 5% 7% 8% 48%	2000
	11th to 20th	Night	6% 3 2 4 4 3 4 4 6% 7% 58%	2027
	21st to end	Night	4 3 1 4 2 3 4 3 4 5% 66%	2280
October	1st to 10th	Night	3 2 1 2 2 2 3 3 5% 7% 70%	3920
	11th to 20th	Night	1 3 1 3 3 3 2 2 4 5% 72%	3898
	21st to end	Night	1 1 1 1 1 1 2 2 3 5% 81%	4252
November	1st to 10th	Night	2 2 1 2 2 2 3 3 4 5% 75%	2460
	11th to 20th	Night	1 3 1 3 2 2 2 2 4 6% 74%	2520
	21st to end	Night	4 4 1 3 2 2 3 3 4 8% 67%	2520
December	1st to 10th	Night	2 3 1 3 2 2 3 2 4 7% 70%	4628
	11th to 20th	Night	1 2 1 3 3 3 4 4 5% 7% 67%	4941
	21st to end	Night	1 3 1 3 3 2 2 2 4 6% 72%	6611

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	18% 4 5% 14% 42% 17%	4189
	11th to 20th	Day	12% 4 6% 15% 35% 29%	4190
	21st to end	Day	19% 4 7% 13% 27% 30%	4609
February	1st to 10th	Day	16% 4 6% 17% 28% 29%	1800
	11th to 20th	Day	17% 3 6% 17% 32% 24%	1909
	21st to end	Day	14% 3 6% 10% 34% 33%	1740
March	1st to 10th	Day	17% 3 4 9% 29% 38%	4954
	11th to 20th	Day	20% 5% 8% 11% 32% 23%	5000
	21st to end	Day	20% 5% 6% 13% 35% 20%	5486
April	1st to 10th	Day	14% 2 6% 12% 36% 28%	2370
	11th to 20th	Day	18% 2 5% 10% 29% 37%	2374
	21st to end	Day	14% 3 6% 13% 36% 28%	2400
May	1st to 10th	Day	15% 4 5% 15% 31% 31%	5440
	11th to 20th	Day	16% 5% 6% 10% 29% 33%	5702
	21st to end	Day	12% 3 4 7% 19% 55%	6424
June	1st to 10th	Day	20% 4 8% 14% 23% 30%	2600
	11th to 20th	Day	15% 4 6% 8% 20% 46%	2600
	21st to end	Day	33% 6% 12% 12% 17% 21%	2600
July	1st to 10th	Day	28% 9% 11% 14% 17% 20%	5816
	11th to 20th	Day	31% 11% 19% 19% 14% 6%	5811
	21st to end	Day	44% 12% 18% 15% 9% 2	6217
August	1st to 10th	Day	32% 10% 16% 26% 14% 3	4191
	11th to 20th	Day	30% 8% 13% 21% 23% 4	3882
	21st to end	Day	40% 11% 15% 13% 18% 3	4311
September	1st to 10th	Day	34% 7% 11% 18% 18% 12%	2400
	11th to 20th	Day	28% 7% 9% 16% 24% 16%	2368
	21st to end	Day	20% 5% 7% 19% 30% 19%	2118
October	1st to 10th	Day	16% 4 6% 10% 30% 35%	3270
	11th to 20th	Day	19% 4 4 10% 40% 23%	3250
	21st to end	Day	8% 1 3 13% 32% 43%	3548
November	1st to 10th	Day	12% 3 5% 18% 36% 27%	2059
	11th to 20th	Day	14% 3 6% 17% 34% 27%	2100
	21st to end	Day	20% 3 8% 15% 31% 23%	2072
December	1st to 10th	Day	13% 3 5% 19% 38% 22%	2758
	11th to 20th	Day	20% 2 6% 11% 40% 21%	3498
	21st to end	Day	12% 4 7% 20% 31% 27%	4609
January	1st to 10th	Night	21% 3 6% 15% 42% 13%	5997
	11th to 20th	Night	9% 3 5% 16% 42% 25%	6010
	21st to end	Night	20% 4 6% 15% 27% 27%	6611
February	1st to 10th	Night	14% 4 8% 20% 29% 25%	2600
	11th to 20th	Night	19% 3 6% 19% 30% 23%	2386
	21st to end	Night	15% 3 6% 15% 28% 32%	1887
March	1st to 10th	Night	11% 4 5% 9% 42% 29%	4940
	11th to 20th	Night	17% 4 5% 14% 39% 21%	5000
	21st to end	Night	12% 4 6% 21% 40% 18%	5489
April	1st to 10th	Night	12% 3 6% 18% 38% 23%	2030
	11th to 20th	Night	15% 3 4 12% 35% 31%	1977
	21st to end	Night	12% 4 5% 15% 37% 27%	2000
May	1st to 10th	Night	13% 3 6% 16% 37% 25%	4537
	11th to 20th	Night	12% 4 6% 12% 34% 32%	4212
	21st to end	Night	10% 2 3 6% 20% 59%	4474
June	1st to 10th	Night	19% 4 7% 14% 26% 30%	1800
	11th to 20th	Night	16% 3 5% 8% 24% 44%	1800
	21st to end	Night	29% 7% 13% 12% 17% 23%	1800
July	1st to 10th	Night	26% 8% 13% 16% 17% 19%	4055
	11th to 20th	Night	27% 9% 23% 20% 16% 4	4046
	21st to end	Night	37% 11% 25% 16% 8% 3	4344
August	1st to 10th	Night	26% 10% 22% 30% 10% 3	2945
	11th to 20th	Night	30% 9% 17% 21% 19% 4	3243
	21st to end	Night	37% 12% 19% 16% 14% 2	3597
September	1st to 10th	Night	31% 9% 12% 18% 18% 12%	2000
	11th to 20th	Night	23% 6% 10% 18% 25% 17%	2027
	21st to end	Night	19% 5% 7% 19% 32% 18%	2280
October	1st to 10th	Night	14% 4 6% 12% 35% 29%	3920
	11th to 20th	Night	15% 4 4 16% 37% 25%	3898
	21st to end	Night	8% 2 3 13% 36% 38%	4252
November	1st to 10th	Night	12% 3 5% 17% 38% 25%	2460
	11th to 20th	Night	13% 3 5% 17% 33% 29%	2520
	21st to end	Night	17% 3 8% 20% 33% 19%	2520
December	1st to 10th	Night	16% 3 6% 20% 35% 21%	4628
	11th to 20th	Night	17% 4 7% 12% 41% 20%	4941
	21st to end	Night	14% 3 7% 21% 34% 22%	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	13% 19% 34% 26% 7% 1	330
	11th to 20th	Day	14% 17% 31% 21% 15% 3	330
	21st to end	Day	8% 19% 33% 27% 12% 2	363
February	1st to 10th	Day	9% 22% 31% 25% 10% 3	300
	11th to 20th	Day	17% 21% 36% 22% 5%	300
	21st to end	Day	23% 29% 25% 18% 3 1	339
March	1st to 10th	Day	16% 28% 34% 16% 4 1	500
	11th to 20th	Day	20% 21% 32% 19% 6% 2	500
	21st to end	Day	16% 31% 33% 15% 4 1	550
April	1st to 10th	Day	13% 24% 36% 18% 8% 2	500
	11th to 20th	Day	16% 26% 37% 14% 5% 1	492
	21st to end	Day	14% 22% 38% 18% 7% 1	500
May	1st to 10th	Day	8% 23% 37% 23% 8% 2	503
	11th to 20th	Day	9% 19% 35% 22% 12% 3	528
	21st to end	Day	9% 16% 38% 24% 12% 1	573
June	1st to 10th	Day	4 9% 35% 32% 16% 4	530
	11th to 20th	Day	5% 8% 31% 36% 17% 4	530
	21st to end	Day	7% 7% 22% 34% 19% 11%	530
July	1st to 10th	Day	9% 2 15% 34% 29% 11%	526
	11th to 20th	Day	6% 1 9% 32% 34% 18%	524
	21st to end	Day	5% 2 9% 26% 38% 20%	575
August	1st to 10th	Day	4 1 10% 28% 38% 19%	527
	11th to 20th	Day	5% 2 12% 34% 31% 16%	517
	21st to end	Day	7% 3 13% 31% 31% 16%	583
September	1st to 10th	Day	9% 3 12% 36% 31% 9%	530
	11th to 20th	Day	5% 5% 23% 37% 23% 6%	530
	21st to end	Day	6% 7% 24% 35% 23% 6%	448
October	1st to 10th	Day	8% 8% 32% 23% 21% 8%	330
	11th to 20th	Day	10% 9% 30% 28% 14% 8%	330
	21st to end	Day	11% 9% 22% 34% 17% 7%	363
November	1st to 10th	Day	7% 13% 32% 32% 14% 4	330
	11th to 20th	Day	5% 12% 25% 34% 19% 5%	330
	21st to end	Day	11% 12% 35% 26% 14% 2	330
December	1st to 10th	Day	8% 12% 36% 31% 12% 2	330
	11th to 20th	Day	10% 17% 30% 26% 13% 4	330
	21st to end	Day	14% 15% 34% 26% 10% 1	363
January	1st to 10th	Night	6% 14% 29% 32% 15% 4	840
	11th to 20th	Night	6% 13% 32% 32% 14% 3	840
	21st to end	Night	7% 13% 33% 31% 13% 3	924
February	1st to 10th	Night	4 17% 33% 30% 13% 3	800
	11th to 20th	Night	7% 17% 41% 26% 9% 1	784
	21st to end	Night	9% 20% 38% 26% 7%	660
March	1st to 10th	Night	5% 22% 35% 29% 8% 1	800
	11th to 20th	Night	6% 16% 33% 30% 14% 1	800
	21st to end	Night	6% 19% 38% 29% 8% 1	880
April	1st to 10th	Night	4 17% 40% 30% 9%	630
	11th to 20th	Night	4 23% 38% 25% 9% 1	593
	21st to end	Night	3 18% 37% 33% 8% 1	600
May	1st to 10th	Night	5% 10% 37% 40% 8%	600
	11th to 20th	Night	4 7% 37% 38% 13% 1	591
	21st to end	Night	4 7% 35% 44% 10% 1	650
June	1st to 10th	Night	5% 2 27% 49% 15% 2	600
	11th to 20th	Night	3 3 29% 45% 19% 1	600
	21st to end	Night	6% 1 17% 43% 30% 3	600
July	1st to 10th	Night	6% 1 8% 38% 41% 6%	585
	11th to 20th	Night	3 6% 29% 55% 6%	582
	21st to end	Night	6% 6% 23% 54% 10%	657
August	1st to 10th	Night	3 1 6% 25% 54% 11%	597
	11th to 20th	Night	4 1 8% 28% 49% 10%	594
	21st to end	Night	6% 1 5% 28% 52% 8%	660
September	1st to 10th	Night	7% 8% 38% 40% 7%	600
	11th to 20th	Night	6% 1 11% 44% 33% 5%	627
	21st to end	Night	5% 3 15% 43% 32% 3	800
October	1st to 10th	Night	5% 4 22% 46% 20% 3	800
	11th to 20th	Night	4 4 27% 42% 20% 3	800
	21st to end	Night	4 7% 23% 38% 22% 6%	880
November	1st to 10th	Night	3 6% 26% 42% 19% 5%	820
	11th to 20th	Night	3 10% 25% 38% 20% 4	840
	21st to end	Night	9% 13% 24% 32% 18% 4	840
December	1st to 10th	Night	7% 11% 29% 38% 13% 3	999
	11th to 20th	Night	6% 12% 32% 35% 13% 2	840
	21st to end	Night	7% 14% 31% 34% 10% 2	924

Page generated at 2026-01-28 23:21:42. Version ac07

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