Watoga State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Watoga State Park clear sky chart from 2005-11-06 to 2026-03-03.

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% 8% 3 7% 5% 5% 5% 4 6% 7% 36%	130483
	Night	13% 8% 3 8% 5% 5% 5% 4 6% 7% 38%	130661
Transparency	Day	45% 6% 10% 21% 14% 3	134088
	Night	44% 6% 11% 22% 14% 3	135126
Seeing	Day	25% 14% 24% 20% 12% 6%	16674
	Night	22% 11% 20% 29% 16% 2	27134

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	14% 12% 4 8% 5% 4 4 3 4 6% 38%	5258
	11th to 20th	Day	9% 10% 6% 12% 7% 5% 4 3 4 4 37%	5280
	21st to end	Day	14% 8% 3 9% 5% 4 4 3 4 6% 41%	5780
February	1st to 10th	Day	13% 9% 4 8% 5% 4 5% 4 5% 6% 38%	1890
	11th to 20th	Day	17% 8% 3 8% 5% 5% 5% 4 5% 6% 34%	1875
	21st to end	Day	17% 10% 4 6% 5% 4 5% 4 4 6% 36%	1793
March	1st to 10th	Day	17% 7% 4 7% 4 5% 5% 4 5% 6% 35%	4957
	11th to 20th	Day	12% 7% 2 6% 3 4 3 4 5% 8% 46%	4980
	21st to end	Day	13% 10% 3 8% 5% 5% 5% 4 5% 6% 36%	5465
April	1st to 10th	Day	12% 10% 3 7% 5% 4 4 4 5% 6% 40%	2276
	11th to 20th	Day	13% 9% 3 7% 5% 4 5% 4 4 7% 41%	2374
	21st to end	Day	17% 8% 3 7% 4 5% 5% 4 5% 6% 35%	2570
May	1st to 10th	Day	15% 7% 3 9% 6% 6% 7% 5% 8% 8% 26%	5862
	11th to 20th	Day	21% 8% 3 8% 5% 4 5% 4 6% 8% 27%	5861
	21st to end	Day	15% 7% 3 8% 5% 6% 6% 5% 7% 8% 31%	6433
June	1st to 10th	Day	13% 6% 2 6% 5% 5% 6% 5% 7% 8% 36%	2600
	11th to 20th	Day	11% 6% 3 7% 6% 7% 6% 5% 7% 9% 33%	2600
	21st to end	Day	9% 6% 2 6% 5% 5% 6% 5% 7% 9% 38%	2600
July	1st to 10th	Day	7% 5% 2 7% 6% 6% 6% 5% 7% 10% 39%	5900
	11th to 20th	Day	7% 6% 2 7% 8% 7% 8% 5% 9% 11% 29%	5900
	21st to end	Day	11% 8% 3 9% 7% 7% 6% 5% 8% 10% 25%	6424
August	1st to 10th	Day	14% 7% 2 7% 5% 6% 6% 6% 8% 10% 28%	4234
	11th to 20th	Day	10% 5% 3 9% 7% 7% 7% 6% 8% 9% 30%	4174
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 7% 10% 42%	4387
September	1st to 10th	Day	14% 6% 2 6% 4 4 5% 4 5% 8% 42%	2367
	11th to 20th	Day	14% 8% 2 7% 5% 4 4 4 6% 7% 40%	2200
	21st to end	Day	24% 6% 2 7% 4 4 4 4 5% 6% 33%	2200
October	1st to 10th	Day	16% 6% 2 6% 3 4 3 3 5% 6% 45%	2014
	11th to 20th	Day	16% 7% 2 6% 3 4 3 3 4 6% 47%	2000
	21st to end	Day	15% 9% 2 6% 4 4 3 3 4 7% 44%	2200
November	1st to 10th	Day	11% 8% 3 4 4 3 4 3 5% 6% 49%	2057
	11th to 20th	Day	14% 8% 2 6% 4 4 5% 3 5% 6% 43%	1890
	21st to end	Day	13% 8% 3 7% 5% 3 4 4 5% 7% 41%	1738
December	1st to 10th	Day	13% 11% 4 7% 4 4 4 3 4 5% 41%	2680
	11th to 20th	Day	19% 12% 3 6% 4 4 4 3 4 5% 36%	3099
	21st to end	Day	20% 12% 4 7% 5% 5% 5% 4 5% 6% 29%	4565
January	1st to 10th	Night	11% 10% 5% 10% 7% 6% 6% 4 6% 6% 30%	7635
	11th to 20th	Night	10% 9% 3 10% 7% 4 4 3 4 5% 41%	7680
	21st to end	Night	15% 8% 3 8% 5% 4 4 3 5% 5% 40%	8401
February	1st to 10th	Night	12% 8% 4 8% 6% 4 4 4 6% 7% 37%	2730
	11th to 20th	Night	17% 8% 2 8% 6% 5% 5% 4 5% 6% 33%	2626
	21st to end	Night	15% 8% 3 9% 5% 4 5% 4 6% 7% 35%	2012
March	1st to 10th	Night	17% 11% 3 7% 4 4 4 3 5% 6% 37%	4941
	11th to 20th	Night	10% 5% 3 7% 4 3 4 3 5% 7% 48%	4980
	21st to end	Night	14% 7% 3 7% 5% 4 5% 4 6% 8% 38%	5467
April	1st to 10th	Night	14% 9% 4 7% 5% 4 4 4 5% 7% 38%	2122
	11th to 20th	Night	11% 7% 2 6% 5% 5% 6% 3 6% 8% 41%	1975
	21st to end	Night	15% 5% 2 6% 5% 4 5% 4 6% 7% 41%	1845
May	1st to 10th	Night	17% 9% 3 7% 5% 4 5% 4 7% 8% 31%	4033
	11th to 20th	Night	23% 10% 3 7% 5% 4 4 4 6% 7% 28%	4032
	21st to end	Night	17% 7% 3 8% 6% 5% 5% 4 7% 8% 30%	4421
June	1st to 10th	Night	9% 6% 2 6% 3 4 5% 4 7% 11% 42%	1800
	11th to 20th	Night	12% 5% 2 5% 5% 4 5% 4 7% 9% 43%	1800
	21st to end	Night	9% 4 1 5% 4 4 5% 5% 7% 11% 45%	1800
July	1st to 10th	Night	7% 6% 3 7% 5% 5% 6% 5% 7% 9% 41%	4058
	11th to 20th	Night	9% 8% 3 9% 6% 5% 5% 4 6% 9% 34%	4057
	21st to end	Night	9% 9% 4 9% 6% 7% 6% 5% 7% 9% 29%	4427
August	1st to 10th	Night	15% 6% 3 7% 5% 4 5% 4 6% 9% 35%	2915
	11th to 20th	Night	13% 6% 3 8% 5% 6% 6% 4 6% 9% 35%	2875
	21st to end	Night	9% 6% 2 5% 4 4 3 3 5% 8% 51%	3477
September	1st to 10th	Night	12% 5% 2 5% 4 3 5% 4 6% 8% 46%	2029
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 5% 7% 46%	2200
	21st to end	Night	22% 7% 2 5% 4 4 3 4 6% 5% 37%	2200
October	1st to 10th	Night	15% 6% 2 5% 4 3 4 3 5% 6% 47%	2385
	11th to 20th	Night	12% 8% 3 6% 4 5% 3 3 5% 6% 45%	2400
	21st to end	Night	14% 7% 2 6% 3 4 4 3 5% 7% 45%	2640
November	1st to 10th	Night	11% 7% 3 7% 4 4 3 3 4 7% 46%	2461
	11th to 20th	Night	14% 6% 3 5% 4 5% 4 4 6% 8% 41%	2725
	21st to end	Night	13% 7% 3 7% 5% 5% 5% 4 6% 6% 40%	2876
December	1st to 10th	Night	11% 7% 4 8% 5% 5% 5% 4 6% 7% 39%	4720
	11th to 20th	Night	19% 9% 4 9% 5% 5% 4 2 4 6% 32%	5283
	21st to end	Night	18% 7% 5% 7% 5% 5% 5% 5% 6% 7% 30%	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	48% 4 8% 19% 19% 3	5259
	11th to 20th	Day	49% 4 6% 14% 18% 9%	5280
	21st to end	Day	46% 3 7% 27% 13% 4	5780
February	1st to 10th	Day	48% 4 9% 21% 15% 3	1890
	11th to 20th	Day	51% 5% 8% 18% 15% 3	1884
	21st to end	Day	50% 5% 8% 19% 14% 4	1793
March	1st to 10th	Day	48% 5% 8% 20% 13% 6%	4957
	11th to 20th	Day	37% 5% 7% 23% 22% 6%	4980
	21st to end	Day	48% 6% 8% 18% 17% 4	5465
April	1st to 10th	Day	46% 5% 10% 19% 15% 5%	2276
	11th to 20th	Day	43% 5% 10% 23% 17% 3	2374
	21st to end	Day	49% 5% 11% 21% 12% 2	2570
May	1st to 10th	Day	52% 9% 11% 18% 9% 2	5897
	11th to 20th	Day	53% 7% 10% 20% 8% 1	5865
	21st to end	Day	47% 8% 13% 18% 10% 3	6447
June	1st to 10th	Day	42% 9% 13% 21% 15%	2600
	11th to 20th	Day	45% 8% 14% 18% 15% 1	2600
	21st to end	Day	41% 9% 13% 24% 11% 2	2600
July	1st to 10th	Day	39% 9% 15% 22% 10% 4	5835
	11th to 20th	Day	44% 11% 16% 22% 7%	5831
	21st to end	Day	51% 7% 13% 21% 8%	6240
August	1st to 10th	Day	48% 9% 16% 20% 7%	4221
	11th to 20th	Day	47% 8% 11% 22% 11%	4213
	21st to end	Day	36% 7% 16% 28% 12% 1	4387
September	1st to 10th	Day	40% 6% 11% 19% 18% 4	2367
	11th to 20th	Day	43% 5% 8% 23% 19% 2	2200
	21st to end	Day	51% 5% 9% 18% 15% 2	2200
October	1st to 10th	Day	31% 5% 7% 22% 27% 7%	3274
	11th to 20th	Day	32% 3 10% 25% 16% 15%	3240
	21st to end	Day	30% 3 9% 30% 16% 13%	3538
November	1st to 10th	Day	36% 4 10% 23% 23% 4	2057
	11th to 20th	Day	42% 3 8% 20% 22% 4	1890
	21st to end	Day	44% 4 11% 22% 17% 2	1738
December	1st to 10th	Day	46% 4 6% 21% 20% 3	2680
	11th to 20th	Day	51% 4 8% 18% 16% 3	3095
	21st to end	Day	55% 5% 9% 18% 12% 1	4565
January	1st to 10th	Night	51% 7% 8% 17% 15% 3	7636
	11th to 20th	Night	45% 4 6% 20% 19% 7%	7680
	21st to end	Night	46% 3 7% 25% 16% 2	8401
February	1st to 10th	Night	46% 5% 12% 21% 15% 2	2730
	11th to 20th	Night	52% 5% 8% 18% 14% 3	2628
	21st to end	Night	48% 6% 10% 20% 11% 5%	2012
March	1st to 10th	Night	47% 5% 7% 20% 16% 6%	4941
	11th to 20th	Night	35% 5% 8% 26% 22% 4	4980
	21st to end	Night	43% 6% 11% 20% 16% 3	5467
April	1st to 10th	Night	47% 6% 11% 19% 15% 3	2122
	11th to 20th	Night	40% 7% 13% 21% 16% 4	1975
	21st to end	Night	41% 6% 13% 26% 13% 1	1845
May	1st to 10th	Night	50% 9% 14% 17% 9% 1	4060
	11th to 20th	Night	54% 8% 13% 20% 6%	4033
	21st to end	Night	49% 9% 16% 19% 4 3	4429
June	1st to 10th	Night	35% 11% 14% 25% 15%	1800
	11th to 20th	Night	36% 10% 19% 23% 12% 1	1800
	21st to end	Night	32% 10% 19% 27% 12% 1	1800
July	1st to 10th	Night	38% 11% 16% 24% 10% 2	4015
	11th to 20th	Night	45% 10% 17% 22% 6% 1	4006
	21st to end	Night	48% 10% 15% 20% 8%	4297
August	1st to 10th	Night	45% 8% 17% 24% 5%	2904
	11th to 20th	Night	44% 9% 14% 22% 11% 1	2902
	21st to end	Night	32% 7% 16% 32% 13% 1	3477
September	1st to 10th	Night	36% 9% 15% 18% 19% 4	2029
	11th to 20th	Night	38% 6% 10% 25% 20% 2	2200
	21st to end	Night	48% 7% 10% 21% 14% 1	2200
October	1st to 10th	Night	35% 4 7% 26% 24% 4	3905
	11th to 20th	Night	35% 4 9% 19% 21% 12%	3899
	21st to end	Night	27% 3 11% 27% 21% 11%	4252
November	1st to 10th	Night	39% 4 11% 20% 21% 5%	2461
	11th to 20th	Night	41% 5% 9% 22% 20% 4	2725
	21st to end	Night	44% 5% 9% 22% 16% 3	2876
December	1st to 10th	Night	42% 5% 9% 25% 17% 1	4720
	11th to 20th	Night	54% 5% 10% 17% 13% 1	5286
	21st to end	Night	51% 7% 11% 19% 12%	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	43% 22% 20% 10% 4 1	330
	11th to 20th	Day	44% 24% 23% 8% 2	330
	21st to end	Day	42% 23% 23% 9% 4	363
February	1st to 10th	Day	37% 23% 27% 10% 3	330
	11th to 20th	Day	53% 19% 18% 8% 2	330
	21st to end	Day	40% 21% 26% 10% 2	336
March	1st to 10th	Day	34% 22% 22% 16% 6%	508
	11th to 20th	Day	34% 22% 22% 16% 5% 1	500
	21st to end	Day	29% 21% 28% 15% 6% 1	550
April	1st to 10th	Day	32% 22% 22% 15% 8% 1	500
	11th to 20th	Day	23% 19% 28% 17% 10% 3	492
	21st to end	Day	30% 17% 27% 13% 10% 3	500
May	1st to 10th	Day	27% 16% 30% 14% 8% 4	503
	11th to 20th	Day	25% 13% 27% 19% 11% 5%	527
	21st to end	Day	20% 11% 23% 22% 16% 8%	573
June	1st to 10th	Day	16% 11% 28% 22% 15% 8%	530
	11th to 20th	Day	16% 9% 27% 22% 18% 8%	530
	21st to end	Day	11% 9% 29% 28% 14% 9%	530
July	1st to 10th	Day	13% 6% 22% 26% 20% 13%	525
	11th to 20th	Day	6% 5% 24% 30% 22% 13%	524
	21st to end	Day	15% 5% 22% 27% 20% 11%	576
August	1st to 10th	Day	18% 7% 20% 21% 20% 13%	526
	11th to 20th	Day	14% 4 21% 24% 22% 14%	519
	21st to end	Day	12% 4 20% 25% 21% 17%	583
September	1st to 10th	Day	15% 6% 20% 24% 22% 14%	530
	11th to 20th	Day	16% 5% 15% 28% 23% 12%	530
	21st to end	Day	28% 9% 21% 24% 13% 5%	530
October	1st to 10th	Day	20% 9% 19% 27% 19% 6%	530
	11th to 20th	Day	24% 13% 23% 22% 15% 3	530
	21st to end	Day	28% 14% 25% 21% 11% 2	583
November	1st to 10th	Day	22% 15% 29% 21% 10% 3	535
	11th to 20th	Day	36% 15% 28% 15% 5%	330
	21st to end	Day	32% 20% 27% 16% 4 1	250
December	1st to 10th	Day	32% 25% 26% 10% 5% 1	220
	11th to 20th	Day	32% 22% 23% 14% 7% 1	228
	21st to end	Day	36% 21% 24% 15% 4 1	363
January	1st to 10th	Night	31% 20% 25% 21% 4	840
	11th to 20th	Night	32% 15% 27% 23% 4	840
	21st to end	Night	29% 18% 28% 22% 2	924
February	1st to 10th	Night	26% 18% 25% 28% 3	840
	11th to 20th	Night	33% 21% 27% 18% 2	823
	21st to end	Night	28% 18% 29% 22% 2	692
March	1st to 10th	Night	26% 17% 29% 23% 4	809
	11th to 20th	Night	27% 18% 23% 25% 6% 1	800
	21st to end	Night	24% 18% 26% 24% 7% 1	880
April	1st to 10th	Night	24% 19% 25% 26% 6%	800
	11th to 20th	Night	21% 13% 25% 29% 12% 1	791
	21st to end	Night	21% 11% 22% 34% 11% 1	645
May	1st to 10th	Night	21% 9% 24% 31% 14% 1	600
	11th to 20th	Night	24% 8% 19% 32% 16% 1	591
	21st to end	Night	18% 3 17% 28% 30% 4	650
June	1st to 10th	Night	12% 3 17% 37% 30% 3	600
	11th to 20th	Night	14% 2 15% 34% 32% 3	600
	21st to end	Night	11% 3 13% 40% 29% 5%	600
July	1st to 10th	Night	11% 2 11% 33% 36% 7%	585
	11th to 20th	Night	8% 1 8% 32% 44% 6%	582
	21st to end	Night	8% 3 10% 37% 36% 5%	657
August	1st to 10th	Night	16% 2 9% 34% 35% 4	597
	11th to 20th	Night	15% 3 7% 33% 37% 5%	594
	21st to end	Night	13% 2 10% 32% 37% 6%	810
September	1st to 10th	Night	15% 3 12% 34% 30% 7%	800
	11th to 20th	Night	18% 4 11% 30% 33% 5%	800
	21st to end	Night	28% 4 15% 29% 23% 2	800
October	1st to 10th	Night	20% 7% 13% 29% 27% 4	800
	11th to 20th	Night	19% 13% 21% 29% 17% 1	800
	21st to end	Night	21% 11% 18% 34% 14% 1	880
November	1st to 10th	Night	18% 10% 20% 36% 14% 2	820
	11th to 20th	Night	26% 12% 19% 32% 10% 1	840
	21st to end	Night	24% 15% 20% 33% 8% 1	840
December	1st to 10th	Night	28% 17% 25% 25% 5%	840
	11th to 20th	Night	24% 17% 24% 29% 5%	840
	21st to end	Night	29% 12% 23% 31% 5%	924

Page generated at 2026-02-28 01:40:24. Version ac07

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