Stonelick Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stonelick Lake State Park clear sky chart from 2005-11-06 to 2026-10-29.

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	14% 9% 3 8% 5% 5% 5% 4 5% 8% 35%	150153
	Night	14% 9% 4 8% 5% 4 4 4 5% 7% 36%	141973
Transparency	Day	45% 6% 11% 22% 13% 1	153795
	Night	46% 6% 11% 22% 14% 2	146391
Seeing	Day	17% 11% 26% 23% 15% 7%	17945
	Night	18% 9% 27% 29% 15% 2	27356

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	17% 14% 8% 12% 5% 4 3 3 4 6% 23%	5258
	11th to 20th	Day	12% 13% 5% 17% 6% 6% 4 3 3 4 27%	5280
	21st to end	Day	19% 12% 6% 10% 7% 7% 5% 4 4 5% 20%	5780
February	1st to 10th	Day	19% 13% 5% 9% 5% 4 4 3 4 5% 28%	1974
	11th to 20th	Day	17% 11% 5% 11% 6% 5% 4 3 4 5% 29%	2048
	21st to end	Day	16% 14% 5% 10% 4 4 3 3 4 6% 31%	1730
March	1st to 10th	Day	17% 14% 5% 9% 4 4 3 3 4 5% 30%	4666
	11th to 20th	Day	13% 8% 3 7% 5% 4 4 4 5% 8% 39%	5090
	21st to end	Day	16% 10% 3 7% 5% 4 4 3 5% 7% 34%	5586
April	1st to 10th	Day	15% 8% 4 7% 5% 5% 4 4 6% 7% 35%	2446
	11th to 20th	Day	15% 8% 3 8% 5% 5% 4 4 5% 6% 39%	2571
	21st to end	Day	17% 8% 3 7% 5% 4 5% 4 5% 7% 36%	2730
May	1st to 10th	Day	18% 8% 3 8% 5% 5% 5% 4 6% 8% 31%	7616
	11th to 20th	Day	17% 8% 3 7% 5% 4 4 4 5% 8% 36%	7626
	21st to end	Day	18% 8% 3 7% 5% 6% 6% 5% 7% 8% 29%	8391
June	1st to 10th	Day	12% 6% 2 6% 5% 5% 6% 5% 6% 8% 40%	2730
	11th to 20th	Day	9% 6% 2 6% 5% 5% 5% 4 6% 10% 42%	2865
	21st to end	Day	9% 6% 3 6% 5% 5% 5% 4 7% 10% 41%	2940
July	1st to 10th	Day	9% 6% 2 7% 5% 5% 5% 4 7% 9% 41%	8280
	11th to 20th	Day	10% 6% 2 6% 4 5% 5% 4 7% 11% 38%	7800
	21st to end	Day	9% 7% 2 8% 6% 6% 7% 5% 7% 10% 34%	8340
August	1st to 10th	Day	10% 6% 2 6% 4 5% 6% 4 7% 10% 39%	6014
	11th to 20th	Day	11% 8% 3 8% 5% 5% 6% 5% 7% 9% 34%	5951
	21st to end	Day	5% 4 1 5% 3 3 4 3 6% 10% 57%	6196
September	1st to 10th	Day	11% 5% 2 6% 4 4 3 3 4 7% 51%	2371
	11th to 20th	Day	9% 5% 2 5% 3 4 4 4 6% 9% 49%	2310
	21st to end	Day	16% 6% 2 6% 4 4 3 2 5% 6% 46%	2310
October	1st to 10th	Day	11% 4 2 4 4 4 5% 4 5% 6% 51%	2310
	11th to 20th	Day	14% 6% 2 5% 4 4 4 2 5% 7% 47%	2112
	21st to end	Day	19% 8% 3 6% 4 3 3 3 4 7% 40%	2152
November	1st to 10th	Day	10% 8% 2 6% 3 3 4 3 5% 6% 50%	1852
	11th to 20th	Day	14% 11% 4 7% 5% 4 4 4 5% 5% 36%	1890
	21st to end	Day	17% 12% 4 8% 4 5% 3 3 4 6% 34%	1890
December	1st to 10th	Day	18% 10% 4 8% 5% 3 4 3 3 5% 36%	3020
	11th to 20th	Day	19% 13% 5% 10% 5% 5% 5% 4 5% 5% 25%	3463
	21st to end	Day	21% 19% 5% 10% 5% 5% 4 3 4 5% 19%	4565
January	1st to 10th	Night	13% 14% 6% 14% 8% 5% 5% 4 5% 5% 21%	7635
	11th to 20th	Night	12% 15% 7% 14% 7% 5% 5% 3 4 5% 23%	7680
	21st to end	Night	18% 12% 5% 9% 5% 5% 4 3 4 5% 31%	8401
February	1st to 10th	Night	20% 13% 4 8% 5% 4 4 3 5% 5% 29%	2641
	11th to 20th	Night	18% 11% 4 8% 4 5% 4 3 5% 6% 30%	2458
	21st to end	Night	19% 14% 5% 8% 4 4 3 3 4 6% 31%	2076
March	1st to 10th	Night	19% 12% 3 7% 4 4 3 2 4 5% 37%	5407
	11th to 20th	Night	12% 7% 2 6% 4 4 5% 4 6% 8% 42%	5090
	21st to end	Night	17% 9% 4 8% 5% 4 4 3 5% 6% 34%	5588
April	1st to 10th	Night	16% 9% 3 6% 4 4 5% 4 6% 6% 38%	2191
	11th to 20th	Night	14% 8% 2 5% 4 4 5% 4 7% 7% 41%	1996
	21st to end	Night	16% 7% 3 6% 4 4 4 3 7% 7% 38%	1890
May	1st to 10th	Night	20% 8% 3 7% 5% 4 5% 4 6% 7% 30%	5237
	11th to 20th	Night	15% 6% 3 7% 4 4 5% 5% 7% 8% 37%	5234
	21st to end	Night	16% 8% 3 7% 5% 5% 5% 4 6% 9% 34%	5761
June	1st to 10th	Night	9% 5% 2 5% 5% 4 4 4 6% 8% 49%	1890
	11th to 20th	Night	9% 4 2 5% 4 3 6% 3 7% 11% 47%	1746
	21st to end	Night	7% 4 2 5% 4 5% 5% 6% 7% 10% 45%	1680
July	1st to 10th	Night	8% 6% 2 7% 4 4 5% 4 6% 8% 46%	4708
	11th to 20th	Night	9% 7% 2 7% 4 4 5% 4 7% 9% 42%	5158
	21st to end	Night	8% 5% 2 8% 5% 5% 6% 5% 7% 10% 40%	5736
August	1st to 10th	Night	10% 8% 3 8% 5% 4 5% 4 6% 8% 39%	4135
	11th to 20th	Night	12% 7% 3 9% 5% 4 4 4 5% 8% 39%	4095
	21st to end	Night	3 2 1 4 3 4 4 4 7% 10% 58%	4926
September	1st to 10th	Night	10% 5% 2 5% 3 3 4 3 5% 7% 53%	2227
	11th to 20th	Night	7% 5% 2 5% 4 3 4 4 6% 7% 53%	2310
	21st to end	Night	14% 7% 2 5% 4 4 3 3 4 6% 48%	2310
October	1st to 10th	Night	8% 4 2 5% 3 4 3 3 5% 6% 55%	2310
	11th to 20th	Night	13% 7% 2 6% 4 4 4 3 5% 7% 46%	2506
	21st to end	Night	18% 7% 2 5% 4 4 4 3 5% 6% 42%	2860
November	1st to 10th	Night	13% 7% 2 6% 4 4 3 3 5% 6% 46%	2666
	11th to 20th	Night	15% 9% 3 7% 4 3 3 3 5% 7% 40%	2730
	21st to end	Night	18% 14% 4 7% 5% 4 4 3 5% 6% 31%	2730
December	1st to 10th	Night	16% 11% 4 8% 4 4 3 3 4 5% 37%	4380
	11th to 20th	Night	19% 14% 6% 9% 5% 5% 4 3 4 6% 26%	4952
	21st to end	Night	21% 18% 7% 11% 6% 5% 4 3 4 5% 17%	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	63% 4 13% 15% 5%	5259
	11th to 20th	Day	60% 5% 9% 13% 12% 2	5280
	21st to end	Day	66% 3 10% 14% 6% 1	5780
February	1st to 10th	Day	58% 4 10% 18% 9% 1	1974
	11th to 20th	Day	57% 5% 10% 17% 10% 1	2058
	21st to end	Day	55% 5% 10% 20% 8% 1	1730
March	1st to 10th	Day	55% 5% 8% 19% 12% 2	4666
	11th to 20th	Day	43% 6% 9% 27% 14% 1	5090
	21st to end	Day	48% 5% 12% 21% 12% 2	5586
April	1st to 10th	Day	46% 7% 12% 23% 12% 1	2446
	11th to 20th	Day	45% 6% 11% 22% 14% 3	2571
	21st to end	Day	47% 7% 11% 22% 11% 2	2730
May	1st to 10th	Day	50% 6% 12% 20% 10% 1	7651
	11th to 20th	Day	46% 5% 12% 24% 12%	7630
	21st to end	Day	49% 8% 11% 18% 11% 2	8405
June	1st to 10th	Day	39% 9% 12% 22% 16% 2	2730
	11th to 20th	Day	36% 9% 14% 23% 16% 1	2865
	21st to end	Day	37% 9% 15% 22% 14% 3	2940
July	1st to 10th	Day	38% 7% 13% 26% 16% 1	8211
	11th to 20th	Day	38% 7% 12% 30% 12%	7729
	21st to end	Day	43% 7% 12% 22% 14% 2	8156
August	1st to 10th	Day	38% 8% 15% 26% 11% 2	6001
	11th to 20th	Day	44% 7% 12% 26% 11%	5990
	21st to end	Day	24% 6% 17% 33% 18% 2	6195
September	1st to 10th	Day	33% 6% 11% 25% 21% 5%	2371
	11th to 20th	Day	31% 6% 13% 24% 23% 3	2310
	21st to end	Day	40% 5% 9% 21% 22% 2	2310
October	1st to 10th	Day	23% 5% 8% 30% 32% 2	3700
	11th to 20th	Day	30% 4 9% 29% 26% 2	3352
	21st to end	Day	35% 3 11% 25% 24% 3	3402
November	1st to 10th	Day	35% 5% 11% 28% 20% 2	1852
	11th to 20th	Day	49% 5% 8% 21% 15% 3	1890
	21st to end	Day	52% 4 10% 21% 12% 1	1890
December	1st to 10th	Day	52% 4 10% 25% 9%	3020
	11th to 20th	Day	62% 5% 8% 18% 7%	3460
	21st to end	Day	67% 5% 10% 12% 5% 1	4565
January	1st to 10th	Night	64% 5% 9% 14% 8%	7636
	11th to 20th	Night	64% 4 8% 13% 10% 3	7680
	21st to end	Night	55% 4 11% 20% 9% 1	8401
February	1st to 10th	Night	56% 5% 11% 19% 8% 1	2641
	11th to 20th	Night	54% 5% 10% 19% 11% 1	2459
	21st to end	Night	55% 4 11% 17% 10% 2	2076
March	1st to 10th	Night	50% 4 6% 26% 11% 2	5407
	11th to 20th	Night	38% 6% 12% 28% 15% 1	5090
	21st to end	Night	51% 5% 8% 24% 11% 2	5588
April	1st to 10th	Night	44% 8% 11% 23% 12% 2	2191
	11th to 20th	Night	40% 7% 12% 19% 17% 5%	1996
	21st to end	Night	44% 7% 10% 22% 14% 3	1890
May	1st to 10th	Night	50% 7% 10% 21% 9% 3	5264
	11th to 20th	Night	43% 8% 14% 22% 13% 1	5235
	21st to end	Night	45% 7% 15% 18% 11% 4	5771
June	1st to 10th	Night	31% 7% 12% 25% 21% 2	1890
	11th to 20th	Night	30% 9% 16% 22% 19% 4	1746
	21st to end	Night	30% 11% 17% 22% 16% 4	1680
July	1st to 10th	Night	36% 7% 13% 24% 18% 3	4670
	11th to 20th	Night	37% 7% 12% 29% 13% 1	5110
	21st to end	Night	38% 6% 13% 24% 16% 3	5606
August	1st to 10th	Night	41% 7% 13% 25% 12% 2	4124
	11th to 20th	Night	43% 7% 14% 23% 13% 1	4122
	21st to end	Night	20% 6% 17% 35% 20% 2	4926
September	1st to 10th	Night	29% 7% 12% 25% 20% 6%	2227
	11th to 20th	Night	28% 7% 12% 23% 27% 3	2310
	21st to end	Night	38% 5% 9% 20% 25% 3	2310
October	1st to 10th	Night	22% 4 8% 25% 38% 3	3700
	11th to 20th	Night	27% 4 9% 25% 31% 3	4005
	21st to end	Night	32% 3 9% 23% 27% 6%	4547
November	1st to 10th	Night	38% 5% 10% 22% 21% 4	2666
	11th to 20th	Night	44% 5% 9% 21% 17% 3	2730
	21st to end	Night	54% 4 10% 20% 10% 2	2730
December	1st to 10th	Night	51% 4 11% 24% 10%	4380
	11th to 20th	Night	59% 5% 11% 18% 7% 1	4954
	21st to end	Night	69% 5% 8% 14% 4	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	23% 23% 35% 14% 5%	330
	11th to 20th	Day	25% 25% 36% 11% 2	330
	21st to end	Day	29% 21% 34% 13% 2	363
February	1st to 10th	Day	27% 21% 34% 15% 4	330
	11th to 20th	Day	29% 24% 35% 11% 2	330
	21st to end	Day	27% 19% 44% 10% 1	273
March	1st to 10th	Day	23% 26% 35% 14% 2	364
	11th to 20th	Day	24% 18% 36% 16% 5%	540
	21st to end	Day	27% 19% 32% 18% 5%	594
April	1st to 10th	Day	20% 19% 31% 21% 8% 1	540
	11th to 20th	Day	20% 20% 27% 21% 10% 2	532
	21st to end	Day	21% 14% 35% 19% 10% 2	540
May	1st to 10th	Day	22% 14% 34% 18% 8% 3	543
	11th to 20th	Day	20% 10% 26% 26% 13% 5%	567
	21st to end	Day	16% 6% 26% 26% 18% 8%	617
June	1st to 10th	Day	12% 6% 23% 29% 22% 8%	570
	11th to 20th	Day	11% 6% 22% 32% 22% 7%	705
	21st to end	Day	11% 4 22% 32% 22% 9%	780
July	1st to 10th	Day	12% 4 16% 24% 25% 19%	771
	11th to 20th	Day	9% 3 19% 29% 27% 13%	604
	21st to end	Day	11% 3 16% 30% 25% 14%	620
August	1st to 10th	Day	11% 3 13% 28% 28% 16%	566
	11th to 20th	Day	11% 4 19% 29% 25% 12%	559
	21st to end	Day	8% 4 14% 29% 30% 15%	627
September	1st to 10th	Day	11% 4 16% 28% 30% 12%	570
	11th to 20th	Day	10% 3 14% 24% 34% 15%	570
	21st to end	Day	19% 8% 19% 24% 21% 8%	570
October	1st to 10th	Day	10% 5% 23% 33% 21% 8%	570
	11th to 20th	Day	16% 12% 30% 23% 14% 5%	570
	21st to end	Day	21% 13% 33% 23% 8% 2	487
November	1st to 10th	Day	17% 11% 35% 25% 10% 3	330
	11th to 20th	Day	21% 22% 28% 21% 6% 2	330
	21st to end	Day	24% 15% 40% 18% 3	330
December	1st to 10th	Day	21% 20% 40% 15% 4 1	330
	11th to 20th	Day	20% 21% 40% 15% 5%	330
	21st to end	Day	30% 20% 33% 14% 2	363
January	1st to 10th	Night	20% 20% 35% 21% 4	840
	11th to 20th	Night	26% 17% 36% 19% 3	840
	21st to end	Night	22% 16% 36% 23% 2	924
February	1st to 10th	Night	27% 12% 35% 25% 2	840
	11th to 20th	Night	24% 16% 37% 21% 2	823
	21st to end	Night	26% 13% 38% 21% 1	692
March	1st to 10th	Night	23% 14% 35% 23% 5%	840
	11th to 20th	Night	22% 15% 35% 22% 6% 1	840
	21st to end	Night	23% 10% 35% 26% 6%	924
April	1st to 10th	Night	20% 13% 34% 26% 7%	721
	11th to 20th	Night	17% 12% 33% 27% 10% 1	623
	21st to end	Night	18% 9% 37% 27% 8% 1	630
May	1st to 10th	Night	21% 7% 32% 28% 10% 1	630
	11th to 20th	Night	17% 5% 26% 34% 17% 2	621
	21st to end	Night	10% 2 23% 37% 22% 5%	683
June	1st to 10th	Night	9% 3 20% 43% 24% 1	630
	11th to 20th	Night	11% 4 15% 42% 26% 2	630
	21st to end	Night	8% 2 19% 42% 27% 3	630
July	1st to 10th	Night	11% 2 12% 33% 34% 9%	615
	11th to 20th	Night	7% 3 14% 36% 37% 4	612
	21st to end	Night	11% 1 11% 40% 33% 4	690
August	1st to 10th	Night	8% 3 11% 41% 34% 4	627
	11th to 20th	Night	10% 2 12% 42% 29% 5%	624
	21st to end	Night	7% 1 14% 35% 36% 7%	693
September	1st to 10th	Night	13% 1 14% 34% 33% 4	757
	11th to 20th	Night	9% 3 15% 35% 33% 6%	840
	21st to end	Night	16% 5% 21% 32% 24% 2	840
October	1st to 10th	Night	11% 4 21% 38% 23% 3	840
	11th to 20th	Night	17% 9% 26% 33% 14% 1	840
	21st to end	Night	21% 8% 32% 27% 12%	913
November	1st to 10th	Night	17% 9% 31% 28% 14% 1	820
	11th to 20th	Night	18% 16% 32% 25% 9% 1	840
	21st to end	Night	25% 13% 26% 28% 7% 1	840
December	1st to 10th	Night	25% 13% 34% 23% 5%	840
	11th to 20th	Night	25% 11% 35% 23% 5% 1	840
	21st to end	Night	29% 14% 32% 22% 3	924

Page generated at 2026-10-26 04:37:53. Version ac07

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