Douthat State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Douthat State Park clear sky chart from 2005-11-06 to 2025-12-18.

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% 6% 2 7% 5% 5% 5% 4 6% 8% 38%	126404
	Night	14% 7% 2 6% 4 4 4 4 6% 7% 42%	124580
Transparency	Day	41% 8% 12% 21% 15% 4	130009
	Night	39% 7% 12% 22% 16% 4	129044
Seeing	Day	23% 13% 24% 22% 13% 5%	16474
	Night	19% 10% 20% 32% 16% 2	26685

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	13% 8% 2 6% 5% 5% 4 3 4 5% 44%	4056
	11th to 20th	Day	12% 7% 4 8% 6% 5% 4 3 4 5% 43%	4060
	21st to end	Day	16% 7% 3 6% 4 4 3 3 4 6% 45%	4466
February	1st to 10th	Day	14% 9% 3 7% 5% 5% 5% 4 5% 7% 38%	1800
	11th to 20th	Day	17% 7% 3 7% 5% 5% 4 4 5% 7% 36%	1764
	21st to end	Day	17% 9% 3 6% 4 5% 4 4 5% 5% 39%	1732
March	1st to 10th	Day	17% 7% 2 5% 4 5% 5% 4 6% 7% 37%	4935
	11th to 20th	Day	12% 6% 1 5% 4 3 4 3 5% 8% 49%	4980
	21st to end	Day	14% 8% 3 8% 5% 5% 4 3 5% 6% 39%	5465
April	1st to 10th	Day	13% 7% 2 7% 5% 5% 4 3 5% 7% 43%	2291
	11th to 20th	Day	13% 5% 2 6% 5% 4 5% 4 5% 6% 44%	2374
	21st to end	Day	16% 7% 2 6% 5% 4 4 3 6% 5% 40%	2535
May	1st to 10th	Day	14% 6% 3 8% 6% 6% 7% 5% 7% 9% 30%	5862
	11th to 20th	Day	22% 7% 3 7% 5% 5% 4 4 6% 8% 28%	5861
	21st to end	Day	15% 5% 2 6% 4 6% 6% 5% 7% 9% 35%	6433
June	1st to 10th	Day	11% 4 2 6% 6% 5% 6% 5% 7% 9% 39%	2628
	11th to 20th	Day	9% 6% 3 7% 6% 5% 6% 5% 8% 10% 35%	2735
	21st to end	Day	9% 5% 2 6% 5% 6% 6% 5% 8% 11% 38%	2600
July	1st to 10th	Day	7% 5% 2 7% 5% 6% 6% 5% 8% 10% 40%	5900
	11th to 20th	Day	8% 5% 2 7% 6% 7% 7% 6% 9% 12% 30%	5900
	21st to end	Day	11% 7% 3 8% 7% 6% 6% 5% 8% 10% 29%	6424
August	1st to 10th	Day	14% 6% 2 7% 6% 6% 6% 5% 8% 10% 30%	4234
	11th to 20th	Day	9% 5% 2 7% 6% 6% 6% 5% 9% 10% 35%	4174
	21st to end	Day	9% 4 2 5% 4 5% 5% 4 7% 10% 46%	4350
September	1st to 10th	Day	13% 6% 2 6% 3 5% 4 4 5% 6% 46%	2395
	11th to 20th	Day	15% 6% 2 6% 4 4 4 3 5% 8% 41%	2200
	21st to end	Day	24% 7% 3 7% 4 4 4 3 5% 6% 33%	2197
October	1st to 10th	Day	15% 6% 3 5% 4 4 3 3 5% 7% 47%	2000
	11th to 20th	Day	15% 5% 2 5% 3 4 3 2 5% 6% 49%	2000
	21st to end	Day	15% 6% 2 6% 4 4 3 2 4 5% 48%	2200
November	1st to 10th	Day	10% 6% 2 5% 4 3 3 3 5% 6% 52%	2057
	11th to 20th	Day	14% 5% 2 5% 4 3 4 3 6% 7% 47%	1925
	21st to end	Day	14% 6% 2 6% 4 3 3 4 4 6% 47%	1706
December	1st to 10th	Day	11% 9% 3 6% 4 4 4 3 5% 6% 45%	2680
	11th to 20th	Day	19% 8% 2 5% 4 4 4 4 4 7% 40%	3046
	21st to end	Day	20% 8% 3 8% 6% 5% 4 4 5% 6% 30%	4439
January	1st to 10th	Night	11% 8% 2 6% 4 5% 6% 3 5% 6% 44%	5889
	11th to 20th	Night	12% 7% 3 7% 5% 4 3 3 4 5% 47%	5900
	21st to end	Night	16% 8% 2 5% 3 3 3 3 4 5% 48%	6490
February	1st to 10th	Night	13% 8% 3 7% 5% 4 4 3 7% 7% 40%	2600
	11th to 20th	Night	18% 9% 2 7% 4 4 4 4 5% 6% 38%	2518
	21st to end	Night	15% 7% 3 6% 5% 4 5% 4 6% 6% 39%	1896
March	1st to 10th	Night	18% 7% 2 5% 4 3 4 3 5% 5% 43%	4918
	11th to 20th	Night	11% 5% 2 6% 4 4 3 3 6% 7% 50%	4980
	21st to end	Night	14% 6% 2 6% 4 5% 4 4 5% 7% 43%	5467
April	1st to 10th	Night	14% 7% 2 7% 4 4 4 4 5% 7% 41%	2107
	11th to 20th	Night	12% 6% 2 4 4 5% 4 5% 6% 8% 45%	1975
	21st to end	Night	15% 4 2 5% 5% 4 4 4 6% 8% 43%	1880
May	1st to 10th	Night	16% 8% 3 7% 4 4 4 4 6% 9% 36%	4033
	11th to 20th	Night	23% 9% 3 7% 5% 5% 4 3 5% 7% 29%	4032
	21st to end	Night	16% 6% 3 7% 5% 5% 5% 5% 7% 8% 35%	4421
June	1st to 10th	Night	10% 5% 3 6% 3 3 5% 5% 6% 11% 43%	1751
	11th to 20th	Night	11% 5% 2 6% 4 5% 4 4 7% 9% 44%	1641
	21st to end	Night	8% 5% 1 5% 4 5% 5% 4 7% 10% 46%	1800
July	1st to 10th	Night	8% 5% 2 7% 5% 5% 5% 5% 8% 11% 41%	4058
	11th to 20th	Night	10% 7% 3 8% 5% 5% 6% 5% 8% 11% 32%	4057
	21st to end	Night	10% 9% 3 10% 6% 5% 6% 5% 8% 10% 29%	4427
August	1st to 10th	Night	16% 7% 2 6% 5% 5% 5% 5% 7% 9% 33%	2915
	11th to 20th	Night	11% 6% 3 7% 6% 6% 5% 5% 7% 8% 37%	2875
	21st to end	Night	9% 5% 2 5% 4 4 5% 4 6% 9% 46%	3514
September	1st to 10th	Night	11% 5% 2 7% 4 4 4 4 5% 6% 48%	2001
	11th to 20th	Night	15% 7% 3 5% 4 4 4 3 4 7% 44%	2200
	21st to end	Night	22% 7% 2 6% 4 4 4 3 5% 6% 36%	2201
October	1st to 10th	Night	15% 6% 2 4 4 4 3 3 5% 6% 47%	2400
	11th to 20th	Night	13% 6% 2 6% 4 3 4 3 5% 5% 48%	2400
	21st to end	Night	14% 4 2 5% 4 3 3 3 5% 6% 51%	2640
November	1st to 10th	Night	11% 7% 2 6% 3 3 3 2 4 6% 51%	2461
	11th to 20th	Night	13% 5% 1 5% 4 3 4 4 5% 7% 49%	2692
	21st to end	Night	12% 6% 2 6% 4 3 4 3 5% 6% 47%	2909
December	1st to 10th	Night	11% 7% 2 6% 4 4 4 3 5% 6% 48%	4720
	11th to 20th	Night	17% 10% 3 6% 4 4 5% 4 5% 6% 36%	5304
	21st to end	Night	18% 6% 2 7% 5% 5% 6% 4 6% 8% 35%	6508

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	41% 5% 6% 20% 22% 6%	4057
	11th to 20th	Day	41% 6% 8% 15% 19% 10%	4060
	21st to end	Day	42% 4 7% 25% 19% 4	4466
February	1st to 10th	Day	45% 7% 10% 20% 15% 3	1800
	11th to 20th	Day	47% 5% 10% 20% 15% 3	1773
	21st to end	Day	46% 6% 9% 18% 16% 5%	1732
March	1st to 10th	Day	45% 5% 9% 18% 15% 8%	4935
	11th to 20th	Day	33% 6% 8% 24% 22% 8%	4980
	21st to end	Day	45% 6% 9% 18% 17% 5%	5465
April	1st to 10th	Day	40% 6% 11% 20% 16% 6%	2291
	11th to 20th	Day	38% 6% 12% 21% 18% 4	2374
	21st to end	Day	44% 7% 10% 23% 12% 4	2535
May	1st to 10th	Day	45% 10% 13% 20% 9% 2	5897
	11th to 20th	Day	52% 8% 10% 19% 10% 1	5865
	21st to end	Day	41% 10% 14% 18% 13% 3	6447
June	1st to 10th	Day	38% 10% 14% 23% 14% 1	2628
	11th to 20th	Day	40% 11% 15% 19% 15% 1	2735
	21st to end	Day	37% 10% 14% 25% 13% 2	2600
July	1st to 10th	Day	36% 11% 18% 21% 10% 4	5835
	11th to 20th	Day	41% 14% 18% 20% 7% 1	5831
	21st to end	Day	45% 10% 15% 21% 9%	6240
August	1st to 10th	Day	44% 10% 17% 21% 7%	4221
	11th to 20th	Day	38% 10% 13% 27% 11% 1	4213
	21st to end	Day	32% 8% 19% 25% 14% 1	4350
September	1st to 10th	Day	37% 8% 12% 18% 20% 5%	2395
	11th to 20th	Day	41% 7% 9% 24% 18% 3	2200
	21st to end	Day	51% 6% 10% 17% 15% 2	2197
October	1st to 10th	Day	32% 5% 8% 21% 26% 8%	3260
	11th to 20th	Day	26% 4 10% 25% 21% 14%	3240
	21st to end	Day	26% 4 9% 29% 19% 12%	3538
November	1st to 10th	Day	33% 5% 9% 22% 26% 4	2057
	11th to 20th	Day	36% 5% 9% 21% 23% 6%	1925
	21st to end	Day	38% 5% 11% 24% 19% 2	1706
December	1st to 10th	Day	40% 6% 9% 20% 20% 5%	2680
	11th to 20th	Day	44% 4 12% 19% 17% 4	3042
	21st to end	Day	50% 8% 11% 17% 13% 1	4439
January	1st to 10th	Night	36% 7% 9% 20% 21% 7%	5889
	11th to 20th	Night	37% 7% 7% 23% 18% 8%	5900
	21st to end	Night	40% 4 7% 27% 19% 4	6490
February	1st to 10th	Night	41% 6% 12% 23% 16% 2	2600
	11th to 20th	Night	47% 5% 9% 18% 16% 5%	2520
	21st to end	Night	43% 6% 11% 22% 13% 5%	1896
March	1st to 10th	Night	42% 5% 9% 20% 18% 7%	4918
	11th to 20th	Night	31% 5% 9% 24% 25% 5%	4980
	21st to end	Night	41% 6% 11% 20% 18% 4	5467
April	1st to 10th	Night	40% 7% 14% 18% 16% 4	2107
	11th to 20th	Night	36% 6% 14% 20% 19% 5%	1975
	21st to end	Night	38% 6% 13% 26% 15% 2	1880
May	1st to 10th	Night	45% 10% 14% 20% 10% 1	4060
	11th to 20th	Night	54% 8% 11% 18% 9% 1	4033
	21st to end	Night	43% 10% 16% 22% 6% 3	4429
June	1st to 10th	Night	34% 11% 15% 24% 15% 1	1751
	11th to 20th	Night	34% 10% 18% 23% 13% 2	1641
	21st to end	Night	32% 11% 16% 23% 15% 2	1800
July	1st to 10th	Night	36% 13% 17% 21% 12% 2	4015
	11th to 20th	Night	45% 12% 17% 19% 6% 1	4006
	21st to end	Night	48% 11% 14% 18% 9%	4297
August	1st to 10th	Night	45% 10% 18% 22% 5%	2904
	11th to 20th	Night	41% 8% 15% 22% 12%	2902
	21st to end	Night	33% 8% 16% 30% 11% 2	3514
September	1st to 10th	Night	35% 8% 15% 18% 19% 5%	2001
	11th to 20th	Night	40% 7% 11% 23% 18% 2	2200
	21st to end	Night	48% 7% 10% 18% 14% 2	2201
October	1st to 10th	Night	36% 7% 10% 20% 22% 5%	3920
	11th to 20th	Night	27% 6% 9% 21% 27% 9%	3899
	21st to end	Night	22% 4 11% 28% 26% 10%	4252
November	1st to 10th	Night	35% 4 9% 22% 24% 6%	2461
	11th to 20th	Night	34% 5% 10% 23% 21% 5%	2692
	21st to end	Night	38% 5% 10% 25% 19% 4	2909
December	1st to 10th	Night	37% 5% 9% 27% 20% 2	4720
	11th to 20th	Night	48% 5% 12% 18% 14% 3	5307
	21st to end	Night	44% 7% 15% 20% 13% 1	6508

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	42% 17% 26% 11% 3 1	300
	11th to 20th	Day	43% 21% 23% 12% 2	300
	21st to end	Day	38% 23% 24% 11% 4	330
February	1st to 10th	Day	33% 23% 30% 10% 3 1	300
	11th to 20th	Day	47% 20% 24% 8% 1	300
	21st to end	Day	36% 20% 30% 11% 2	331
March	1st to 10th	Day	32% 22% 23% 19% 5%	500
	11th to 20th	Day	31% 22% 23% 20% 3 1	500
	21st to end	Day	29% 22% 25% 18% 6% 1	550
April	1st to 10th	Day	29% 23% 23% 18% 7% 1	500
	11th to 20th	Day	23% 17% 29% 19% 10% 3	492
	21st to end	Day	27% 16% 27% 17% 9% 4	500
May	1st to 10th	Day	25% 18% 27% 18% 9% 3	503
	11th to 20th	Day	26% 13% 24% 20% 13% 4	527
	21st to end	Day	21% 10% 23% 22% 16% 8%	573
June	1st to 10th	Day	16% 9% 30% 24% 15% 7%	530
	11th to 20th	Day	15% 7% 27% 25% 19% 8%	530
	21st to end	Day	11% 8% 28% 27% 18% 8%	530
July	1st to 10th	Day	11% 4 21% 28% 23% 12%	525
	11th to 20th	Day	8% 3 21% 31% 25% 11%	524
	21st to end	Day	13% 5% 23% 27% 22% 11%	576
August	1st to 10th	Day	18% 6% 23% 21% 21% 12%	526
	11th to 20th	Day	14% 4 20% 28% 23% 11%	519
	21st to end	Day	14% 3 18% 28% 24% 14%	583
September	1st to 10th	Day	15% 5% 20% 26% 23% 12%	530
	11th to 20th	Day	17% 4 17% 29% 24% 8%	530
	21st to end	Day	31% 7% 21% 24% 14% 3	530
October	1st to 10th	Day	20% 8% 19% 29% 20% 4	530
	11th to 20th	Day	21% 13% 22% 27% 15% 2	530
	21st to end	Day	24% 13% 26% 25% 10% 2	583
November	1st to 10th	Day	19% 13% 29% 26% 10% 2	535
	11th to 20th	Day	30% 17% 27% 19% 7% 1	365
	21st to end	Day	31% 19% 24% 18% 6% 2	234
December	1st to 10th	Day	28% 23% 31% 14% 4	220
	11th to 20th	Day	34% 16% 26% 17% 6% 1	214
	21st to end	Day	30% 18% 29% 17% 6%	324
January	1st to 10th	Night	27% 19% 28% 22% 3	800
	11th to 20th	Night	27% 16% 24% 29% 3	800
	21st to end	Night	23% 19% 32% 24% 2	880
February	1st to 10th	Night	21% 18% 27% 31% 3	800
	11th to 20th	Night	30% 21% 26% 21% 1	783
	21st to end	Night	24% 17% 33% 24% 2	660
March	1st to 10th	Night	22% 16% 30% 27% 5%	800
	11th to 20th	Night	27% 16% 26% 24% 7% 1	800
	21st to end	Night	21% 15% 28% 28% 7% 1	880
April	1st to 10th	Night	22% 18% 25% 30% 6%	800
	11th to 20th	Night	19% 14% 26% 29% 12% 1	791
	21st to end	Night	18% 11% 23% 36% 11% 1	680
May	1st to 10th	Night	19% 7% 23% 36% 13% 2	600
	11th to 20th	Night	22% 8% 17% 36% 16% 1	591
	21st to end	Night	16% 2 15% 35% 28% 4	650
June	1st to 10th	Night	12% 3 13% 42% 28% 2	551
	11th to 20th	Night	11% 2 10% 41% 33% 2	441
	21st to end	Night	10% 3 11% 43% 29% 4	600
July	1st to 10th	Night	12% 2 9% 38% 34% 5%	585
	11th to 20th	Night	7% 1 7% 32% 47% 5%	582
	21st to end	Night	10% 3 9% 37% 38% 4	657
August	1st to 10th	Night	16% 3 8% 36% 34% 4	597
	11th to 20th	Night	16% 2 7% 34% 37% 5%	594
	21st to end	Night	12% 2 8% 35% 36% 6%	834
September	1st to 10th	Night	13% 4 10% 34% 34% 6%	800
	11th to 20th	Night	18% 4 10% 31% 33% 5%	800
	21st to end	Night	26% 5% 14% 31% 22% 2	800
October	1st to 10th	Night	18% 7% 16% 30% 26% 3	800
	11th to 20th	Night	19% 10% 21% 33% 16% 1	800
	21st to end	Night	18% 10% 20% 37% 13% 2	880
November	1st to 10th	Night	17% 9% 23% 35% 14% 1	820
	11th to 20th	Night	22% 12% 22% 33% 10% 1	840
	21st to end	Night	20% 13% 24% 33% 9% 1	840
December	1st to 10th	Night	25% 15% 28% 27% 5%	840
	11th to 20th	Night	21% 14% 25% 36% 5%	829
	21st to end	Night	23% 14% 24% 36% 4	880

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