Cricket Hill
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cricket Hill clear sky chart from 2005-11-06 to 2025-09-19.

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% 8% 3 7% 5% 5% 5% 4 6% 7% 38%	126215
	Night	15% 10% 4 7% 5% 4 4 4 5% 6% 37%	123049
Transparency	Day	43% 7% 13% 23% 13% 2	129740
	Night	46% 6% 12% 21% 13% 2	127585
Seeing	Day	14% 6% 23% 33% 19% 5%	17031
	Night	18% 8% 26% 30% 15% 2	26808

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	12% 10% 8% 11% 6% 6% 5% 5% 6% 6% 25%	3617
	11th to 20th	Day	11% 11% 6% 11% 5% 5% 7% 8% 5% 4 27%	3620
	21st to end	Day	17% 17% 5% 7% 4 3 3 3 4 6% 31%	4028
February	1st to 10th	Day	14% 13% 4 10% 6% 5% 5% 4 6% 6% 26%	1869
	11th to 20th	Day	14% 11% 4 8% 6% 5% 4 4 5% 6% 34%	1948
	21st to end	Day	12% 12% 5% 10% 5% 5% 5% 4 6% 5% 31%	1650
March	1st to 10th	Day	16% 10% 3 7% 4 4 4 3 4 5% 42%	4480
	11th to 20th	Day	8% 6% 3 6% 4 5% 5% 4 6% 8% 43%	4661
	21st to end	Day	18% 12% 6% 11% 6% 5% 5% 4 5% 6% 22%	5967
April	1st to 10th	Day	17% 11% 3 7% 5% 5% 3 3 5% 7% 33%	2400
	11th to 20th	Day	14% 7% 3 6% 5% 6% 6% 4 6% 7% 37%	2374
	21st to end	Day	17% 8% 3 7% 5% 5% 5% 4 5% 8% 34%	2535
May	1st to 10th	Day	18% 7% 2 6% 5% 4 5% 4 6% 8% 35%	5862
	11th to 20th	Day	14% 5% 3 7% 5% 4 4 3 6% 8% 41%	6105
	21st to end	Day	14% 6% 2 6% 4 4 4 4 5% 8% 43%	6935
June	1st to 10th	Day	10% 6% 2 5% 4 5% 5% 4 6% 8% 46%	2800
	11th to 20th	Day	10% 5% 2 5% 4 5% 5% 4 7% 9% 45%	2800
	21st to end	Day	10% 5% 2 6% 5% 5% 5% 5% 6% 9% 41%	2800
July	1st to 10th	Day	10% 6% 2 6% 5% 5% 5% 5% 7% 9% 39%	6360
	11th to 20th	Day	9% 4 2 5% 4 4 5% 4 7% 10% 46%	6360
	21st to end	Day	10% 6% 2 7% 4 5% 5% 4 7% 9% 42%	6924
August	1st to 10th	Day	11% 4 2 5% 4 4 5% 4 6% 8% 48%	4431
	11th to 20th	Day	10% 4 1 5% 4 3 4 4 6% 8% 51%	3923
	21st to end	Day	7% 4 2 6% 4 4 4 3 6% 9% 51%	4312
September	1st to 10th	Day	12% 4 2 5% 4 4 4 3 6% 8% 49%	2400
	11th to 20th	Day	11% 4 2 3 3 3 3 3 5% 8% 53%	2229
	21st to end	Day	12% 6% 2 6% 5% 4 5% 4 6% 8% 41%	2090
October	1st to 10th	Day	14% 7% 3 6% 4 4 4 3 5% 5% 46%	2070
	11th to 20th	Day	19% 7% 3 8% 5% 4 4 5% 4 6% 36%	1862
	21st to end	Day	19% 10% 2 6% 4 6% 5% 3 5% 6% 33%	1881
November	1st to 10th	Day	12% 9% 3 6% 4 4 4 3 5% 7% 42%	1762
	11th to 20th	Day	15% 11% 4 10% 6% 6% 4 4 5% 6% 30%	1800
	21st to end	Day	18% 11% 3 9% 5% 6% 4 3 3 5% 33%	1760
December	1st to 10th	Day	10% 10% 5% 8% 6% 6% 5% 5% 5% 6% 35%	2610
	11th to 20th	Day	13% 15% 6% 12% 6% 6% 5% 4 6% 6% 22%	3008
	21st to end	Day	23% 21% 6% 11% 5% 5% 4 3 4 4 13%	3982
January	1st to 10th	Night	14% 14% 7% 11% 6% 4 4 3 5% 5% 26%	6348
	11th to 20th	Night	15% 15% 6% 13% 6% 5% 5% 6% 5% 4 20%	6360
	21st to end	Night	18% 15% 6% 7% 4 3 3 3 4 4 32%	6936
February	1st to 10th	Night	16% 14% 5% 8% 5% 4 4 3 5% 6% 30%	2530
	11th to 20th	Night	14% 11% 3 8% 4 5% 5% 4 5% 6% 35%	2338
	21st to end	Night	19% 12% 3 8% 4 4 4 3 4 4 35%	1980
March	1st to 10th	Night	17% 10% 4 7% 4 3 4 3 4 5% 40%	5373
	11th to 20th	Night	10% 6% 2 6% 4 4 4 4 5% 7% 47%	5314
	21st to end	Night	18% 12% 6% 8% 5% 5% 5% 4 4 5% 29%	4976
April	1st to 10th	Night	17% 8% 3 6% 5% 4 5% 4 4 7% 37%	2000
	11th to 20th	Night	19% 8% 2 5% 4 5% 4 3 6% 5% 38%	1975
	21st to end	Night	17% 8% 3 6% 5% 4 4 3 5% 6% 38%	1864
May	1st to 10th	Night	19% 7% 3 7% 5% 4 4 3 5% 7% 34%	4033
	11th to 20th	Night	15% 7% 4 7% 4 3 4 4 5% 8% 40%	3785
	21st to end	Night	18% 7% 3 6% 5% 3 3 3 4 6% 42%	3942
June	1st to 10th	Night	9% 6% 2 4 5% 5% 4 3 6% 8% 47%	1600
	11th to 20th	Night	11% 7% 2 5% 4 4 5% 5% 6% 9% 44%	1600
	21st to end	Night	10% 6% 2 6% 5% 4 5% 4 7% 9% 42%	1600
July	1st to 10th	Night	11% 4 2 6% 5% 5% 5% 5% 6% 9% 41%	3618
	11th to 20th	Night	8% 4 2 6% 4 4 4 4 5% 8% 50%	3617
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 7% 8% 45%	3947
August	1st to 10th	Night	9% 4 2 6% 4 5% 5% 4 6% 8% 48%	2722
	11th to 20th	Night	9% 4 2 5% 4 4 4 4 6% 7% 52%	3122
	21st to end	Night	9% 5% 2 5% 4 4 4 3 5% 7% 52%	3586
September	1st to 10th	Night	11% 5% 2 5% 4 3 4 3 5% 7% 50%	2000
	11th to 20th	Night	11% 4 2 5% 3 3 4 3 5% 8% 54%	2107
	21st to end	Night	13% 5% 2 7% 4 4 4 3 5% 8% 44%	2090
October	1st to 10th	Night	14% 5% 1 6% 4 4 3 3 5% 6% 48%	2107
	11th to 20th	Night	18% 8% 2 7% 4 4 4 3 4 6% 41%	2316
	21st to end	Night	22% 8% 3 7% 4 3 3 3 5% 8% 35%	2717
November	1st to 10th	Night	13% 8% 2 6% 4 4 4 3 4 6% 44%	2536
	11th to 20th	Night	16% 11% 4 8% 5% 5% 4 4 6% 7% 32%	2600
	21st to end	Night	17% 12% 3 8% 5% 5% 4 3 5% 5% 33%	2635
December	1st to 10th	Night	12% 11% 3 8% 6% 5% 5% 4 5% 7% 35%	4580
	11th to 20th	Night	16% 16% 5% 9% 5% 5% 5% 4 5% 6% 26%	5199
	21st to end	Night	24% 19% 6% 9% 6% 4 4 3 4 5% 16%	6996

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	58% 8% 14% 14% 7%	3618
	11th to 20th	Day	55% 7% 13% 9% 12% 3	3620
	21st to end	Day	54% 4 12% 21% 8%	4028
February	1st to 10th	Day	57% 8% 13% 14% 8% 1	1869
	11th to 20th	Day	51% 8% 10% 22% 9% 1	1958
	21st to end	Day	52% 9% 12% 16% 10% 2	1650
March	1st to 10th	Day	45% 6% 11% 23% 11% 4	4480
	11th to 20th	Day	35% 9% 13% 33% 9% 1	4661
	21st to end	Day	61% 10% 11% 11% 6%	5969
April	1st to 10th	Day	50% 7% 13% 19% 11%	2400
	11th to 20th	Day	45% 8% 11% 21% 12% 3	2374
	21st to end	Day	47% 8% 14% 18% 11% 2	2535
May	1st to 10th	Day	43% 8% 13% 21% 12% 2	5897
	11th to 20th	Day	41% 8% 11% 26% 14% 1	6109
	21st to end	Day	38% 7% 12% 25% 15% 3	6949
June	1st to 10th	Day	34% 8% 13% 24% 18% 2	2800
	11th to 20th	Day	34% 8% 13% 24% 19% 3	2800
	21st to end	Day	36% 10% 15% 21% 15% 3	2800
July	1st to 10th	Day	39% 7% 13% 26% 14% 2	6291
	11th to 20th	Day	33% 8% 15% 28% 15% 1	6285
	21st to end	Day	37% 8% 16% 21% 16% 2	6728
August	1st to 10th	Day	33% 7% 17% 28% 13% 1	4416
	11th to 20th	Day	30% 8% 12% 33% 16% 1	3961
	21st to end	Day	30% 6% 15% 26% 20% 2	4311
September	1st to 10th	Day	33% 8% 14% 25% 17% 3	2400
	11th to 20th	Day	28% 6% 13% 30% 20% 2	2229
	21st to end	Day	39% 8% 12% 24% 17% 1	2090
October	1st to 10th	Day	27% 5% 7% 37% 23% 1	3434
	11th to 20th	Day	37% 6% 11% 26% 20%	3078
	21st to end	Day	45% 5% 10% 26% 11% 3	3081
November	1st to 10th	Day	41% 6% 15% 22% 15% 2	1762
	11th to 20th	Day	52% 7% 14% 18% 8% 1	1800
	21st to end	Day	55% 6% 11% 21% 7%	1760
December	1st to 10th	Day	46% 9% 18% 22% 5%	2610
	11th to 20th	Day	61% 6% 12% 16% 5%	3005
	21st to end	Day	74% 7% 7% 9% 3	3982
January	1st to 10th	Night	58% 6% 10% 18% 7%	6348
	11th to 20th	Night	65% 6% 11% 7% 11% 1	6360
	21st to end	Night	56% 4 14% 15% 10%	6936
February	1st to 10th	Night	55% 5% 12% 16% 10% 1	2530
	11th to 20th	Night	49% 6% 13% 21% 11% 1	2339
	21st to end	Night	52% 5% 12% 18% 10% 3	1980
March	1st to 10th	Night	47% 4 11% 24% 11% 2	5373
	11th to 20th	Night	36% 6% 12% 30% 14% 2	5314
	21st to end	Night	57% 6% 9% 18% 9% 1	4976
April	1st to 10th	Night	46% 7% 12% 22% 13% 1	2000
	11th to 20th	Night	46% 7% 8% 19% 17% 3	1975
	21st to end	Night	46% 6% 10% 22% 13% 2	1864
May	1st to 10th	Night	49% 7% 10% 16% 15% 4	4060
	11th to 20th	Night	41% 6% 13% 23% 13% 3	3786
	21st to end	Night	44% 6% 9% 21% 17% 4	3950
June	1st to 10th	Night	33% 7% 13% 26% 19% 2	1600
	11th to 20th	Night	35% 6% 12% 25% 21% 2	1600
	21st to end	Night	36% 9% 16% 21% 16% 2	1600
July	1st to 10th	Night	39% 6% 14% 26% 11% 4	3580
	11th to 20th	Night	32% 7% 14% 26% 20% 2	3572
	21st to end	Night	35% 7% 14% 23% 18% 2	3832
August	1st to 10th	Night	33% 7% 15% 27% 16% 1	2713
	11th to 20th	Night	30% 7% 14% 28% 20% 1	3150
	21st to end	Night	30% 6% 12% 32% 18% 3	3586
September	1st to 10th	Night	32% 6% 13% 26% 20% 3	2000
	11th to 20th	Night	29% 5% 9% 28% 27% 2	2107
	21st to end	Night	38% 6% 11% 27% 16% 2	2090
October	1st to 10th	Night	23% 4 8% 38% 25% 2	3510
	11th to 20th	Night	38% 5% 9% 22% 24% 2	3839
	21st to end	Night	42% 5% 10% 25% 17% 2	4467
November	1st to 10th	Night	41% 6% 11% 24% 15% 3	2536
	11th to 20th	Night	50% 7% 13% 20% 9% 1	2600
	21st to end	Night	52% 6% 13% 21% 8%	2635
December	1st to 10th	Night	46% 8% 14% 22% 8% 1	4580
	11th to 20th	Night	58% 7% 13% 14% 7%	5201
	21st to end	Night	70% 6% 9% 10% 4	6996

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	20% 9% 33% 30% 8% 1	300
	11th to 20th	Day	20% 10% 36% 28% 5%	300
	21st to end	Day	22% 10% 31% 31% 6%	330
February	1st to 10th	Day	18% 10% 38% 27% 6% 1	300
	11th to 20th	Day	17% 14% 37% 27% 4	300
	21st to end	Day	14% 9% 43% 29% 6%	249
March	1st to 10th	Day	16% 11% 33% 35% 6%	300
	11th to 20th	Day	18% 10% 35% 30% 7%	347
	21st to end	Day	22% 9% 33% 27% 9% 1	550
April	1st to 10th	Day	21% 10% 32% 30% 8%	500
	11th to 20th	Day	15% 9% 33% 29% 11% 3	492
	21st to end	Day	18% 7% 30% 31% 13% 1	500
May	1st to 10th	Day	20% 5% 28% 32% 13% 2	503
	11th to 20th	Day	18% 2 23% 36% 18% 2	628
	21st to end	Day	14% 3 19% 36% 23% 5%	789
June	1st to 10th	Day	10% 2 19% 40% 25% 4	730
	11th to 20th	Day	11% 1 18% 38% 27% 4	730
	21st to end	Day	9% 4 17% 40% 25% 4	730
July	1st to 10th	Day	8% 2 11% 35% 31% 13%	721
	11th to 20th	Day	10% 2 12% 40% 28% 8%	718
	21st to end	Day	7% 1 13% 40% 32% 6%	794
August	1st to 10th	Day	7% 2 9% 35% 36% 11%	646
	11th to 20th	Day	10% 4 11% 35% 31% 9%	519
	21st to end	Day	7% 3 10% 34% 36% 11%	583
September	1st to 10th	Day	12% 3 17% 29% 30% 8%	530
	11th to 20th	Day	9% 3 11% 31% 32% 15%	522
	21st to end	Day	15% 6% 22% 26% 24% 8%	490
October	1st to 10th	Day	17% 3 23% 31% 20% 6%	470
	11th to 20th	Day	17% 15% 26% 25% 13% 2	300
	21st to end	Day	25% 12% 26% 31% 6% 1	330
November	1st to 10th	Day	13% 9% 28% 33% 16% 1	300
	11th to 20th	Day	19% 14% 34% 22% 10% 1	300
	21st to end	Day	27% 7% 31% 31% 4	300
December	1st to 10th	Day	14% 15% 38% 27% 7%	300
	11th to 20th	Day	15% 14% 40% 25% 6%	300
	21st to end	Day	22% 16% 37% 21% 4	330
January	1st to 10th	Night	18% 14% 39% 23% 5%	1000
	11th to 20th	Night	22% 15% 34% 24% 5% 1	1000
	21st to end	Night	21% 11% 35% 28% 5%	1100
February	1st to 10th	Night	22% 8% 38% 25% 6%	930
	11th to 20th	Night	19% 11% 36% 29% 5%	783
	21st to end	Night	23% 10% 36% 27% 4	660
March	1st to 10th	Night	20% 8% 35% 28% 9%	800
	11th to 20th	Night	15% 8% 31% 36% 9% 1	800
	21st to end	Night	23% 7% 29% 30% 11% 1	674
April	1st to 10th	Night	20% 8% 32% 32% 8% 1	600
	11th to 20th	Night	21% 8% 27% 30% 14% 1	593
	21st to end	Night	20% 7% 26% 32% 15% 1	600
May	1st to 10th	Night	18% 4 23% 39% 14% 1	600
	11th to 20th	Night	18% 3 18% 35% 24% 2	591
	21st to end	Night	15% 2 14% 38% 27% 4	650
June	1st to 10th	Night	11% 2 14% 42% 29% 2	600
	11th to 20th	Night	13% 3 15% 41% 25% 4	600
	21st to end	Night	10% 2 17% 38% 31% 3	600
July	1st to 10th	Night	9% 2 7% 37% 35% 10%	585
	11th to 20th	Night	8% 3 10% 38% 33% 7%	582
	21st to end	Night	6% 1 12% 42% 35% 4	657
August	1st to 10th	Night	7% 1 9% 41% 34% 8%	597
	11th to 20th	Night	8% 3 10% 37% 33% 9%	594
	21st to end	Night	9% 2 13% 33% 37% 6%	660
September	1st to 10th	Night	11% 3 17% 32% 31% 6%	600
	11th to 20th	Night	11% 3 12% 33% 30% 11%	721
	21st to end	Night	14% 7% 20% 29% 23% 7%	760
October	1st to 10th	Night	15% 5% 19% 36% 21% 4	760
	11th to 20th	Night	21% 11% 29% 26% 11% 1	760
	21st to end	Night	26% 11% 29% 25% 10%	836
November	1st to 10th	Night	18% 9% 36% 23% 12% 1	780
	11th to 20th	Night	20% 17% 32% 25% 5% 1	800
	21st to end	Night	21% 13% 35% 25% 6%	835
December	1st to 10th	Night	22% 15% 37% 22% 5%	1000
	11th to 20th	Night	22% 13% 37% 25% 4	1000
	21st to end	Night	29% 14% 35% 19% 3	1100

Page generated at 2025-09-16 00:49:12. Version ac07

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