Green River State Wildlife Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Green River State Wildlife Area clear sky chart from 2005-11-06 to 2024-03-18.

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% 9% 4 7% 6% 3 5% 5% 5% 7% 37%	78611
	Night	14% 9% 4 7% 5% 3 4 4 5% 6% 38%	81227
Transparency	Day	47% 4 12% 23% 12% 2	78312
	Night	47% 3 11% 23% 14% 2	81047
Seeing	Day	16% 10% 27% 26% 15% 5%	14836
	Night	17% 9% 31% 30% 12% 1	24907

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	11% 11% 8% 14% 7% 4 6% 4 4 5% 24%	2527
	11th to 20th	Day	13% 11% 4 13% 9% 4 7% 6% 9% 5% 18%	2530
	21st to end	Day	16% 20% 9% 11% 8% 3 4 4 3 5% 18%	3014
February	1st to 10th	Day	14% 14% 4 10% 6% 3 6% 5% 5% 5% 28%	1710
	11th to 20th	Day	13% 10% 4 6% 7% 4 4 4 5% 7% 36%	1810
	21st to end	Day	14% 13% 6% 10% 5% 4 4 4 4 6% 31%	1570
March	1st to 10th	Day	15% 12% 7% 6% 6% 3 3 3 4 6% 35%	1900
	11th to 20th	Day	14% 9% 3 6% 6% 3 5% 5% 6% 7% 36%	1995
	21st to end	Day	20% 11% 6% 8% 6% 4 5% 4 6% 7% 25%	2340
April	1st to 10th	Day	17% 11% 5% 6% 5% 3 4 4 5% 6% 33%	2160
	11th to 20th	Day	19% 9% 3 6% 5% 3 4 4 4 7% 36%	2134
	21st to end	Day	21% 9% 3 6% 5% 3 4 5% 4 6% 34%	2178
May	1st to 10th	Day	17% 8% 4 7% 6% 3 5% 6% 5% 8% 32%	2368
	11th to 20th	Day	19% 7% 3 7% 6% 4 5% 4 4 7% 34%	2479
	21st to end	Day	14% 6% 2 6% 6% 4 6% 5% 6% 9% 35%	2725
June	1st to 10th	Day	10% 4 2 4 5% 3 5% 5% 7% 9% 46%	2520
	11th to 20th	Day	10% 4 2 5% 5% 3 5% 5% 6% 9% 46%	2520
	21st to end	Day	12% 5% 3 5% 6% 3 6% 6% 7% 10% 38%	2520
July	1st to 10th	Day	8% 4 2 5% 5% 3 5% 6% 6% 8% 48%	2520
	11th to 20th	Day	10% 4 2 4 5% 2 5% 5% 6% 10% 48%	2520
	21st to end	Day	7% 4 2 5% 6% 4 5% 5% 7% 10% 45%	2743
August	1st to 10th	Day	6% 4 2 5% 6% 4 5% 6% 8% 11% 43%	2411
	11th to 20th	Day	10% 5% 2 5% 4 3 5% 4 6% 9% 47%	2147
	21st to end	Day	10% 5% 2 4 4 3 4 5% 4 9% 51%	2376
September	1st to 10th	Day	13% 4 2 5% 5% 2 4 4 5% 9% 45%	2160
	11th to 20th	Day	14% 3 1 3 4 2 3 4 4 7% 55%	2102
	21st to end	Day	10% 6% 2 5% 4 3 4 5% 5% 8% 47%	1980
October	1st to 10th	Day	14% 6% 3 5% 4 2 3 5% 5% 6% 47%	1841
	11th to 20th	Day	18% 8% 3 5% 6% 3 4 3 5% 6% 38%	1800
	21st to end	Day	20% 10% 2 5% 5% 2 3 3 4 5% 39%	1845
November	1st to 10th	Day	11% 7% 3 4 4 3 5% 4 5% 8% 46%	1672
	11th to 20th	Day	16% 11% 5% 7% 5% 3 5% 5% 4 6% 33%	1710
	21st to end	Day	17% 11% 5% 7% 5% 3 4 3 3 6% 36%	1563
December	1st to 10th	Day	14% 13% 5% 8% 5% 4 4 3 4 6% 33%	1520
	11th to 20th	Day	13% 14% 5% 9% 7% 5% 4 4 4 5% 30%	1918
	21st to end	Day	21% 18% 10% 11% 8% 3 3 4 3 4 15%	2783
January	1st to 10th	Night	13% 13% 6% 11% 7% 3 4 3 4 5% 30%	4428
	11th to 20th	Night	13% 16% 7% 11% 8% 3 4 5% 7% 4 21%	4440
	21st to end	Night	19% 18% 8% 9% 6% 3 4 4 4 4 22%	4651
February	1st to 10th	Night	15% 12% 6% 8% 6% 3 4 5% 3 6% 33%	2470
	11th to 20th	Night	13% 9% 3 6% 5% 3 4 5% 4 7% 39%	2256
	21st to end	Night	17% 11% 4 8% 5% 2 3 4 3 6% 36%	1884
March	1st to 10th	Night	17% 10% 3 5% 5% 3 5% 5% 4 5% 38%	2280
	11th to 20th	Night	14% 7% 4 6% 5% 3 5% 5% 5% 7% 40%	2144
	21st to end	Night	20% 10% 4 6% 6% 4 5% 4 5% 6% 30%	2016
April	1st to 10th	Night	16% 10% 4 5% 4 4 4 4 4 7% 38%	1800
	11th to 20th	Night	20% 8% 3 6% 4 3 3 4 4 6% 41%	1775
	21st to end	Night	16% 8% 3 7% 6% 3 5% 5% 6% 7% 35%	1781
May	1st to 10th	Night	15% 7% 3 6% 6% 3 5% 5% 5% 7% 36%	1588
	11th to 20th	Night	16% 7% 3 6% 5% 2 5% 4 5% 8% 39%	1416
	21st to end	Night	13% 6% 2 6% 5% 3 4 5% 7% 8% 42%	1551
June	1st to 10th	Night	9% 4 2 5% 5% 3 5% 6% 5% 8% 49%	1440
	11th to 20th	Night	9% 3 2 5% 5% 2 5% 5% 7% 9% 47%	1440
	21st to end	Night	10% 4 3 5% 5% 3 6% 6% 6% 7% 46%	1440
July	1st to 10th	Night	7% 4 2 5% 4 2 4 5% 7% 9% 52%	1440
	11th to 20th	Night	7% 4 1 3 3 3 5% 4 5% 8% 57%	1440
	21st to end	Night	5% 4 1 5% 4 3 4 5% 8% 10% 50%	1575
August	1st to 10th	Night	6% 4 2 4 5% 4 3 5% 6% 9% 52%	1525
	11th to 20th	Night	8% 3 2 4 4 2 4 4 5% 8% 54%	1753
	21st to end	Night	8% 3 2 4 4 3 3 4 4 7% 57%	1980
September	1st to 10th	Night	10% 5% 2 4 4 2 3 3 4 6% 57%	1800
	11th to 20th	Night	11% 4 2 4 4 3 4 4 5% 7% 54%	1839
	21st to end	Night	9% 4 2 6% 4 3 4 6% 6% 8% 49%	1980
October	1st to 10th	Night	12% 5% 2 5% 5% 3 4 4 4 5% 53%	2114
	11th to 20th	Night	18% 7% 3 5% 5% 2 3 3 4 5% 45%	2160
	21st to end	Night	20% 10% 2 5% 4 3 4 4 4 6% 38%	2510
November	1st to 10th	Night	10% 8% 2 4 4 2 3 4 5% 6% 52%	2406
	11th to 20th	Night	15% 8% 4 7% 5% 3 5% 3 5% 7% 38%	2470
	21st to end	Night	17% 9% 4 6% 5% 3 4 3 4 6% 39%	2612
December	1st to 10th	Night	16% 11% 4 8% 6% 3 5% 4 5% 6% 33%	2660
	11th to 20th	Night	15% 13% 5% 8% 5% 3 4 4 4 6% 33%	3279
	21st to end	Night	22% 16% 7% 10% 7% 4 5% 5% 4 5% 17%	4884

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% 2 12% 16% 6%	2528
	11th to 20th	Day	65% 3 10% 13% 9% 1	2530
	21st to end	Day	72% 2 8% 13% 5%	3014
February	1st to 10th	Day	58% 2 12% 18% 9% 1	1710
	11th to 20th	Day	51% 3 11% 25% 10% 1	1820
	21st to end	Day	56% 3 10% 21% 9% 2	1570
March	1st to 10th	Day	52% 3 13% 22% 9% 1	1900
	11th to 20th	Day	48% 3 14% 24% 9% 1	1995
	21st to end	Day	59% 3 11% 21% 5% 1	2340
April	1st to 10th	Day	52% 3 12% 23% 10%	2160
	11th to 20th	Day	49% 2 10% 25% 12% 2	2134
	21st to end	Day	52% 4 10% 19% 12% 2	2178
May	1st to 10th	Day	51% 4 14% 22% 8% 1	2368
	11th to 20th	Day	51% 5% 9% 24% 11%	2483
	21st to end	Day	46% 5% 13% 20% 14% 2	2725
June	1st to 10th	Day	35% 3 14% 30% 16% 2	2520
	11th to 20th	Day	34% 4 11% 25% 22% 3	2520
	21st to end	Day	40% 6% 13% 25% 14% 2	2520
July	1st to 10th	Day	33% 5% 14% 31% 15% 3	2451
	11th to 20th	Day	31% 5% 16% 30% 15% 3	2445
	21st to end	Day	33% 4 17% 28% 17% 2	2591
August	1st to 10th	Day	34% 6% 15% 31% 13% 1	2396
	11th to 20th	Day	34% 5% 14% 27% 18% 2	2147
	21st to end	Day	31% 5% 11% 30% 20% 3	2376
September	1st to 10th	Day	37% 4 11% 26% 18% 4	2160
	11th to 20th	Day	31% 3 11% 31% 22% 3	2102
	21st to end	Day	35% 4 10% 29% 21% 2	1980
October	1st to 10th	Day	38% 4 9% 28% 20% 1	1841
	11th to 20th	Day	48% 2 10% 24% 15% 2	1800
	21st to end	Day	49% 2 12% 24% 11% 2	1845
November	1st to 10th	Day	38% 3 15% 27% 15% 3	1672
	11th to 20th	Day	52% 2 12% 23% 10% 1	1710
	21st to end	Day	52% 3 14% 22% 8%	1563
December	1st to 10th	Day	55% 2 13% 20% 8% 1	1520
	11th to 20th	Day	58% 3 12% 19% 8% 1	1915
	21st to end	Day	76% 3 8% 8% 5%	2783
January	1st to 10th	Night	59% 1 11% 19% 9%	4428
	11th to 20th	Night	64% 2 11% 13% 10%	4440
	21st to end	Night	67% 2 8% 16% 6% 1	4651
February	1st to 10th	Night	54% 3 9% 19% 13% 1	2470
	11th to 20th	Night	46% 4 10% 25% 14% 1	2257
	21st to end	Night	52% 2 9% 21% 13% 3	1884
March	1st to 10th	Night	49% 3 12% 23% 12% 1	2280
	11th to 20th	Night	45% 4 12% 21% 15% 3	2144
	21st to end	Night	56% 3 11% 19% 10% 1	2016
April	1st to 10th	Night	48% 2 11% 23% 14% 2	1800
	11th to 20th	Night	47% 3 6% 24% 17% 4	1775
	21st to end	Night	48% 4 10% 23% 11% 3	1781
May	1st to 10th	Night	47% 4 12% 24% 12% 1	1588
	11th to 20th	Night	44% 4 11% 26% 15% 1	1417
	21st to end	Night	40% 5% 14% 21% 17% 2	1552
June	1st to 10th	Night	33% 4 13% 27% 19% 3	1440
	11th to 20th	Night	33% 4 11% 24% 24% 4	1440
	21st to end	Night	36% 5% 15% 23% 18% 3	1440
July	1st to 10th	Night	31% 3 15% 31% 17% 4	1400
	11th to 20th	Night	27% 4 12% 31% 22% 3	1392
	21st to end	Night	26% 6% 16% 28% 18% 6%	1487
August	1st to 10th	Night	29% 5% 16% 33% 15% 3	1516
	11th to 20th	Night	28% 4 13% 32% 20% 2	1753
	21st to end	Night	28% 4 11% 29% 24% 5%	1980
September	1st to 10th	Night	31% 3 10% 27% 25% 4	1800
	11th to 20th	Night	30% 3 9% 32% 23% 3	1839
	21st to end	Night	33% 4 9% 29% 21% 3	1980
October	1st to 10th	Night	35% 3 9% 27% 23% 3	2114
	11th to 20th	Night	42% 3 8% 25% 20% 2	2160
	21st to end	Night	48% 3 9% 25% 13% 2	2510
November	1st to 10th	Night	34% 4 12% 28% 19% 4	2406
	11th to 20th	Night	47% 3 11% 25% 13% 2	2470
	21st to end	Night	48% 3 10% 26% 12% 1	2612
December	1st to 10th	Night	53% 3 12% 23% 9% 1	2660
	11th to 20th	Night	55% 2 11% 23% 9% 1	3281
	21st to end	Night	73% 2 7% 13% 5%	4884

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% 10% 36% 25% 8% 1	270
	11th to 20th	Day	20% 13% 43% 17% 6% 1	270
	21st to end	Day	23% 13% 34% 23% 5% 2	297
February	1st to 10th	Day	21% 16% 35% 23% 5%	270
	11th to 20th	Day	23% 17% 31% 23% 6%	270
	21st to end	Day	20% 20% 42% 15% 3	225
March	1st to 10th	Day	23% 20% 33% 18% 6%	270
	11th to 20th	Day	23% 16% 34% 19% 7% 2	261
	21st to end	Day	26% 14% 32% 20% 6% 2	426
April	1st to 10th	Day	26% 14% 30% 24% 6% 1	420
	11th to 20th	Day	20% 19% 28% 21% 10% 3	412
	21st to end	Day	25% 13% 31% 19% 10% 2	420
May	1st to 10th	Day	20% 13% 30% 26% 9% 2	451
	11th to 20th	Day	22% 11% 27% 24% 14% 3	625
	21st to end	Day	14% 8% 28% 23% 17% 9%	679
June	1st to 10th	Day	9% 5% 27% 33% 20% 6%	630
	11th to 20th	Day	11% 5% 28% 34% 17% 6%	630
	21st to end	Day	13% 7% 29% 31% 14% 6%	630
July	1st to 10th	Day	11% 3 14% 29% 26% 18%	621
	11th to 20th	Day	11% 2 21% 32% 23% 10%	618
	21st to end	Day	6% 3 18% 36% 29% 7%	684
August	1st to 10th	Day	6% 2 19% 33% 30% 11%	626
	11th to 20th	Day	10% 6% 14% 29% 25% 16%	461
	21st to end	Day	7% 4 19% 32% 27% 11%	495
September	1st to 10th	Day	15% 5% 20% 31% 22% 7%	450
	11th to 20th	Day	12% 2 20% 32% 24% 11%	450
	21st to end	Day	11% 11% 26% 25% 23% 5%	450
October	1st to 10th	Day	17% 6% 25% 30% 16% 4	311
	11th to 20th	Day	19% 20% 36% 14% 10% 1	270
	21st to end	Day	33% 13% 27% 22% 5%	297
November	1st to 10th	Day	14% 14% 37% 23% 9% 3	270
	11th to 20th	Day	20% 19% 32% 19% 8% 2	270
	21st to end	Day	24% 12% 36% 21% 7%	270
December	1st to 10th	Day	18% 15% 37% 22% 6% 2	270
	11th to 20th	Day	17% 10% 39% 25% 7%	270
	21st to end	Day	24% 19% 37% 17% 3	297
January	1st to 10th	Night	19% 12% 39% 23% 6% 1	950
	11th to 20th	Night	19% 14% 36% 24% 6%	950
	21st to end	Night	22% 11% 35% 28% 4	1045
February	1st to 10th	Night	22% 11% 37% 25% 4	950
	11th to 20th	Night	19% 12% 38% 27% 5%	781
	21st to end	Night	21% 14% 39% 21% 4	628
March	1st to 10th	Night	23% 10% 38% 23% 6% 1	760
	11th to 20th	Night	17% 9% 33% 34% 7%	640
	21st to end	Night	24% 10% 36% 22% 7% 1	594
April	1st to 10th	Night	22% 14% 35% 23% 6%	540
	11th to 20th	Night	23% 13% 32% 26% 7%	533
	21st to end	Night	18% 12% 31% 31% 7% 1	540
May	1st to 10th	Night	18% 8% 34% 31% 7% 1	540
	11th to 20th	Night	20% 5% 30% 34% 11%	531
	21st to end	Night	15% 6% 28% 35% 16% 1	584
June	1st to 10th	Night	9% 4 23% 50% 13% 1	540
	11th to 20th	Night	9% 5% 28% 43% 15% 1	540
	21st to end	Night	11% 4 26% 42% 16%	540
July	1st to 10th	Night	9% 1 13% 42% 30% 5%	525
	11th to 20th	Night	7% 2 20% 42% 25% 3	522
	21st to end	Night	6% 1 17% 46% 28% 2	591
August	1st to 10th	Night	7% 2 14% 42% 32% 4	537
	11th to 20th	Night	8% 2 13% 40% 31% 6%	534
	21st to end	Night	10% 1 16% 41% 30% 3	594
September	1st to 10th	Night	12% 3 18% 38% 25% 4	540
	11th to 20th	Night	10% 4 22% 35% 25% 4	579
	21st to end	Night	11% 7% 27% 34% 19% 2	720
October	1st to 10th	Night	13% 7% 29% 31% 18% 2	720
	11th to 20th	Night	21% 11% 31% 26% 11%	720
	21st to end	Night	26% 10% 32% 24% 7%	792
November	1st to 10th	Night	15% 6% 42% 26% 10% 1	740
	11th to 20th	Night	19% 13% 38% 25% 5%	760
	21st to end	Night	22% 11% 34% 26% 6%	902
December	1st to 10th	Night	22% 12% 37% 24% 5%	950
	11th to 20th	Night	23% 10% 34% 26% 6%	950
	21st to end	Night	27% 14% 34% 23% 2	1045

Page generated at 2024-03-15 13:01:40. Version ac07

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