Eastman Lake Recreation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eastman Lake Recreation Area clear sky chart from 2005-11-06 to 2024-01-14.

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	7% 3 1 3 3 2 3 3 4 5% 67%	74771
	Night	8% 3 1 3 3 2 3 3 4 6% 65%	74993
Transparency	Day	20% 4 8% 19% 25% 24%	74485
	Night	22% 3 9% 20% 24% 21%	74801
Seeing	Day	7% 5% 17% 32% 28% 10%	14130
	Night	8% 2 12% 40% 31% 7%	23710

By Month

Percentage Cloud Cover SW (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	16% 7% 2 6% 5% 3 4 4 5% 7% 39%	1519
	11th to 20th	Day	12% 3 2 4 4 3 4 4 5% 7% 52%	1595
	21st to end	Day	16% 5% 2 4 5% 2 4 5% 5% 7% 44%	1782
February	1st to 10th	Day	14% 5% 2 3 4 2 3 4 5% 6% 52%	1675
	11th to 20th	Day	12% 4 2 4 4 2 4 4 5% 7% 53%	1750
	21st to end	Day	16% 5% 2 3 4 2 3 4 5% 6% 50%	1480
March	1st to 10th	Day	14% 6% 2 5% 5% 2 4 6% 6% 8% 41%	1800
	11th to 20th	Day	14% 5% 2 4 4 3 4 5% 6% 7% 46%	1963
	21st to end	Day	12% 4 1 4 3 2 4 4 5% 7% 54%	2312
April	1st to 10th	Day	10% 4 2 4 3 2 3 3 5% 6% 59%	2160
	11th to 20th	Day	8% 4 2 3 3 2 3 4 4 6% 61%	2129
	21st to end	Day	7% 3 2 2 3 2 3 3 4 6% 66%	2160
May	1st to 10th	Day	3 3 1 2 3 2 2 3 3 5% 72%	2191
	11th to 20th	Day	4 1 1 3 3 1 3 3 4 6% 71%	2344
	21st to end	Day	5% 2 1 2 3 2 3 4 5% 6% 70%	2723
June	1st to 10th	Day	3 2 1 2 2 2 2 3 4 5% 75%	2520
	11th to 20th	Day	1 1 1 1 1 1 1 2 4 86%	2520
	21st to end	Day	1 1 1 1 1 1 1 2 2 3 87%	2520
July	1st to 10th	Day	1 1 1 1 2 2 2 4 87%	2520
	11th to 20th	Day	1 1 1 1 1 2 2 3 3 84%	2520
	21st to end	Day	1 1 1 2 2 1 2 2 3 5% 80%	2573
August	1st to 10th	Day	2 1 1 1 1 1 2 2 2 3 84%	2244
	11th to 20th	Day	1 1 1 1 1 1 2 2 3 87%	2122
	21st to end	Day	1 1 1 1 1 1 2 2 3 87%	2376
September	1st to 10th	Day	1 1 1 1 1 1 1 2 2 88%	2160
	11th to 20th	Day	2 1 1 1 2 1 1 1 2 4 84%	2129
	21st to end	Day	2 1 1 1 1 1 2 2 3 4 83%	1980
October	1st to 10th	Day	3 2 1 2 2 2 3 4 4 5% 74%	1844
	11th to 20th	Day	3 1 1 2 2 2 2 2 4 4 77%	1800
	21st to end	Day	5% 2 1 3 2 1 2 2 4 6% 72%	1980
November	1st to 10th	Day	8% 3 1 2 3 3 3 4 4 8% 61%	1680
	11th to 20th	Day	8% 3 2 2 3 2 3 4 4 7% 62%	1710
	21st to end	Day	10% 3 2 3 3 2 3 4 5% 6% 59%	1710
December	1st to 10th	Day	14% 4 2 4 4 3 4 4 4 8% 49%	1558
	11th to 20th	Day	22% 7% 4 5% 5% 3 3 4 4 7% 36%	1928
	21st to end	Day	13% 7% 4 6% 6% 4 5% 6% 5% 9% 35%	2794
January	1st to 10th	Night	16% 6% 2 4 4 2 3 4 4 8% 45%	2646
	11th to 20th	Night	11% 5% 2 4 4 2 4 5% 4 7% 53%	2432
	21st to end	Night	15% 4 2 4 3 2 3 4 4 8% 51%	2574
February	1st to 10th	Night	14% 4 2 3 3 2 3 4 4 7% 54%	2282
	11th to 20th	Night	11% 3 2 4 3 2 3 3 4 7% 58%	2098
	21st to end	Night	16% 5% 2 3 3 2 2 4 4 6% 52%	1776
March	1st to 10th	Night	16% 6% 3 4 4 2 4 4 3 6% 49%	2160
	11th to 20th	Night	14% 4 2 4 3 2 3 4 5% 8% 52%	1994
	21st to end	Night	12% 4 1 3 3 2 3 3 3 6% 58%	2044
April	1st to 10th	Night	11% 3 2 4 2 2 2 3 4 8% 60%	1800
	11th to 20th	Night	7% 3 1 2 3 2 4 4 5% 5% 65%	1779
	21st to end	Night	6% 2 1 2 2 2 3 3 4 6% 70%	1800
May	1st to 10th	Night	3 2 1 2 3 1 2 3 4 6% 72%	1765
	11th to 20th	Night	4 2 1 2 2 1 2 2 4 5% 75%	1545
	21st to end	Night	3 3 1 3 2 1 3 2 3 5% 76%	1552
June	1st to 10th	Night	3 2 1 2 2 2 2 3 4 6% 75%	1440
	11th to 20th	Night	1 1 1 1 2 2 3 88%	1440
	21st to end	Night	1 1 1 1 1 2 2 2 3 87%	1440
July	1st to 10th	Night	1 1 1 1 1 2 2 90%	1440
	11th to 20th	Night	2 2 1 1 2 1 2 2 3 3 83%	1440
	21st to end	Night	2 1 1 2 2 1 2 3 4 5% 77%	1742
August	1st to 10th	Night	2 2 1 1 1 1 2 2 3 85%	1692
	11th to 20th	Night	1 1 1 2 1 2 2 2 3 84%	1780
	21st to end	Night	1 1 1 1 1 2 3 89%	1980
September	1st to 10th	Night	1 1 1 1 1 1 2 2 89%	1800
	11th to 20th	Night	2 1 1 1 1 1 2 2 2 4 84%	1831
	21st to end	Night	2 1 1 2 1 2 2 2 4 83%	1980
October	1st to 10th	Night	3 2 1 3 2 1 2 3 3 4 75%	2113
	11th to 20th	Night	4 1 1 1 2 1 2 2 4 5% 77%	2160
	21st to end	Night	5% 2 2 2 1 1 1 3 5% 79%	2376
November	1st to 10th	Night	8% 3 1 3 2 2 2 2 4 6% 66%	2397
	11th to 20th	Night	6% 3 1 3 2 2 2 3 5% 7% 66%	2470
	21st to end	Night	9% 3 2 3 2 2 4 3 4 7% 61%	2470
December	1st to 10th	Night	14% 4 3 4 4 2 3 3 4 6% 53%	2617
	11th to 20th	Night	19% 6% 3 6% 5% 3 3 3 5% 7% 40%	3276
	21st to end	Night	15% 6% 2 5% 6% 3 5% 5% 6% 7% 38%	4862

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	43% 7% 16% 20% 12% 3	1519
	11th to 20th	Day	31% 6% 14% 21% 17% 10%	1595
	21st to end	Day	41% 5% 13% 20% 18% 4	1782
February	1st to 10th	Day	32% 5% 11% 25% 19% 7%	1675
	11th to 20th	Day	31% 5% 11% 24% 23% 7%	1760
	21st to end	Day	35% 6% 11% 28% 19% 2	1480
March	1st to 10th	Day	38% 7% 12% 22% 17% 4	1800
	11th to 20th	Day	35% 5% 12% 22% 20% 5%	1963
	21st to end	Day	29% 6% 15% 28% 18% 4	2312
April	1st to 10th	Day	28% 4 12% 28% 20% 9%	2160
	11th to 20th	Day	25% 5% 9% 27% 24% 10%	2132
	21st to end	Day	20% 4 11% 28% 29% 8%	2160
May	1st to 10th	Day	16% 3 10% 23% 35% 13%	2191
	11th to 20th	Day	15% 3 7% 26% 33% 17%	2347
	21st to end	Day	16% 3 9% 30% 30% 11%	2724
June	1st to 10th	Day	13% 3 9% 21% 30% 24%	2520
	11th to 20th	Day	6% 2 5% 16% 36% 37%	2520
	21st to end	Day	6% 1 2 7% 31% 52%	2520
July	1st to 10th	Day	5% 2 1 6% 21% 65%	2451
	11th to 20th	Day	7% 2 3 8% 23% 57%	2445
	21st to end	Day	10% 2 3 9% 23% 53%	2430
August	1st to 10th	Day	9% 1 2 8% 25% 55%	2228
	11th to 20th	Day	5% 1 3 7% 30% 54%	2122
	21st to end	Day	6% 1 2 6% 32% 53%	2376
September	1st to 10th	Day	6% 1 2 7% 26% 57%	2160
	11th to 20th	Day	8% 1 3 18% 39% 31%	2129
	21st to end	Day	8% 2 3 17% 38% 32%	1980
October	1st to 10th	Day	13% 3 6% 19% 28% 31%	1844
	11th to 20th	Day	12% 2 6% 23% 28% 28%	1800
	21st to end	Day	16% 2 7% 21% 31% 24%	1980
November	1st to 10th	Day	23% 4 11% 25% 26% 12%	1680
	11th to 20th	Day	24% 4 14% 26% 25% 7%	1710
	21st to end	Day	27% 4 11% 21% 26% 9%	1710
December	1st to 10th	Day	34% 7% 12% 20% 18% 9%	1558
	11th to 20th	Day	50% 5% 10% 18% 13% 4	1928
	21st to end	Day	45% 10% 16% 19% 8% 2	2794
January	1st to 10th	Night	40% 4 14% 23% 16% 3	2646
	11th to 20th	Night	31% 6% 14% 20% 16% 12%	2432
	21st to end	Night	34% 5% 13% 21% 21% 6%	2574
February	1st to 10th	Night	31% 4 10% 24% 22% 9%	2282
	11th to 20th	Night	27% 3 11% 27% 25% 7%	2099
	21st to end	Night	35% 3 11% 29% 18% 4	1776
March	1st to 10th	Night	36% 5% 13% 21% 20% 5%	2160
	11th to 20th	Night	32% 4 13% 23% 22% 6%	1994
	21st to end	Night	28% 4 15% 28% 20% 5%	2044
April	1st to 10th	Night	26% 3 14% 28% 20% 9%	1800
	11th to 20th	Night	22% 3 12% 27% 26% 9%	1779
	21st to end	Night	17% 4 12% 30% 31% 6%	1800
May	1st to 10th	Night	15% 3 10% 26% 34% 13%	1765
	11th to 20th	Night	14% 2 7% 26% 34% 15%	1546
	21st to end	Night	14% 3 9% 30% 32% 12%	1552
June	1st to 10th	Night	13% 3 8% 24% 32% 20%	1440
	11th to 20th	Night	5% 2 5% 17% 35% 36%	1440
	21st to end	Night	5% 1 2 9% 27% 56%	1440
July	1st to 10th	Night	3 1 1 4 23% 66%	1400
	11th to 20th	Night	8% 2 2 6% 22% 60%	1392
	21st to end	Night	11% 2 3 9% 21% 55%	1645
August	1st to 10th	Night	8% 1 2 10% 25% 55%	1683
	11th to 20th	Night	7% 1 3 8% 27% 54%	1780
	21st to end	Night	5% 1 1 6% 31% 56%	1980
September	1st to 10th	Night	5% 1 2 7% 25% 61%	1800
	11th to 20th	Night	8% 1 3 14% 40% 33%	1831
	21st to end	Night	8% 1 3 13% 38% 36%	1980
October	1st to 10th	Night	14% 3 5% 17% 26% 35%	2113
	11th to 20th	Night	12% 3 7% 20% 28% 31%	2160
	21st to end	Night	12% 2 4 23% 33% 26%	2376
November	1st to 10th	Night	22% 3 9% 24% 25% 17%	2397
	11th to 20th	Night	20% 3 11% 29% 25% 13%	2470
	21st to end	Night	24% 3 10% 23% 29% 10%	2470
December	1st to 10th	Night	33% 4 11% 22% 18% 12%	2617
	11th to 20th	Night	44% 6% 13% 17% 16% 4	3276
	21st to end	Night	42% 8% 16% 22% 8% 3	4862

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	25% 6% 22% 27% 17% 4	180
	11th to 20th	Day	15% 4 12% 33% 25% 10%	297
	21st to end	Day	16% 2 15% 33% 24% 11%	374
February	1st to 10th	Day	15% 7% 15% 28% 24% 12%	365
	11th to 20th	Day	14% 5% 23% 31% 19% 8%	415
	21st to end	Day	14% 8% 19% 35% 20% 3	346
March	1st to 10th	Day	17% 6% 24% 30% 20% 4	420
	11th to 20th	Day	15% 10% 24% 24% 20% 7%	420
	21st to end	Day	16% 10% 24% 26% 20% 4	462
April	1st to 10th	Day	13% 11% 25% 27% 18% 6%	420
	11th to 20th	Day	10% 11% 25% 32% 17% 5%	412
	21st to end	Day	5% 11% 25% 30% 21% 9%	420
May	1st to 10th	Day	5% 8% 27% 35% 19% 7%	423
	11th to 20th	Day	4 6% 27% 34% 21% 7%	448
	21st to end	Day	5% 8% 19% 33% 28% 8%	485
June	1st to 10th	Day	2 5% 22% 34% 28% 9%	450
	11th to 20th	Day	2 4 21% 38% 26% 10%	450
	21st to end	Day	1 3 15% 36% 33% 12%	450
July	1st to 10th	Day	1 8% 37% 40% 14%	446
	11th to 20th	Day	1 5% 33% 45% 16%	444
	21st to end	Day	1 1 7% 35% 40% 16%	487
August	1st to 10th	Day	4 1 13% 39% 32% 11%	447
	11th to 20th	Day	1 12% 38% 34% 14%	437
	21st to end	Day	1 8% 33% 40% 17%	495
September	1st to 10th	Day	2 2 10% 36% 36% 15%	450
	11th to 20th	Day	3 2 20% 34% 30% 10%	450
	21st to end	Day	2 3 14% 32% 37% 12%	450
October	1st to 10th	Day	2 5% 20% 31% 31% 12%	450
	11th to 20th	Day	4 4 17% 27% 33% 15%	450
	21st to end	Day	5% 5% 14% 27% 36% 14%	495
November	1st to 10th	Day	10% 3 13% 27% 32% 15%	276
	11th to 20th	Day	6% 3 13% 33% 33% 14%	270
	21st to end	Day	9% 2 14% 34% 32% 9%	270
December	1st to 10th	Day	17% 3 11% 35% 24% 10%	198
	11th to 20th	Day	15% 4 14% 32% 23% 11%	180
	21st to end	Day	22% 3 17% 27% 23% 8%	198
January	1st to 10th	Night	18% 2 12% 34% 25% 9%	760
	11th to 20th	Night	12% 3 12% 37% 28% 9%	734
	21st to end	Night	17% 1 11% 38% 26% 7%	792
February	1st to 10th	Night	15% 2 11% 37% 24% 10%	720
	11th to 20th	Night	12% 3 13% 36% 27% 9%	704
	21st to end	Night	17% 4 12% 43% 20% 4	592
March	1st to 10th	Night	17% 3 16% 37% 23% 4	720
	11th to 20th	Night	14% 4 15% 34% 26% 7%	720
	21st to end	Night	13% 4 18% 39% 24% 3	792
April	1st to 10th	Night	10% 4 18% 38% 25% 3	720
	11th to 20th	Night	6% 6% 23% 39% 21% 5%	711
	21st to end	Night	6% 5% 22% 38% 23% 6%	720
May	1st to 10th	Night	5% 5% 20% 45% 22% 4	685
	11th to 20th	Night	5% 3 21% 43% 27%	483
	21st to end	Night	5% 5% 20% 38% 31% 1	389
June	1st to 10th	Night	4 5% 20% 45% 23% 2	360
	11th to 20th	Night	1 3 17% 52% 27% 1	360
	21st to end	Night	1 14% 53% 32% 1	360
July	1st to 10th	Night	6% 55% 38% 1	350
	11th to 20th	Night	1 5% 49% 42% 2	348
	21st to end	Night	1 1 4 33% 56% 6%	560
August	1st to 10th	Night	3 7% 45% 39% 6%	618
	11th to 20th	Night	6% 45% 42% 6%	712
	21st to end	Night	2 3 39% 50% 6%	792
September	1st to 10th	Night	1 5% 38% 49% 6%	720
	11th to 20th	Night	2 1 9% 42% 38% 8%	720
	21st to end	Night	2 1 9% 35% 42% 11%	720
October	1st to 10th	Night	4 2 9% 41% 36% 8%	720
	11th to 20th	Night	4 1 9% 35% 40% 11%	720
	21st to end	Night	5% 1 9% 36% 32% 17%	792
November	1st to 10th	Night	9% 2 9% 33% 34% 13%	740
	11th to 20th	Night	7% 1 9% 42% 30% 10%	760
	21st to end	Night	10% 1 11% 38% 30% 10%	760
December	1st to 10th	Night	16% 2 10% 38% 27% 7%	760
	11th to 20th	Night	17% 3 9% 41% 26% 4	760
	21st to end	Night	18% 3 12% 42% 21% 5%	836

Page generated at 2024-01-11 01:22:37. Version ac07

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