Lamoine Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lamoine Observatory 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	19% 7% 3 5% 5% 3 4 4 5% 7% 38%	74586
	Night	20% 8% 3 5% 5% 3 4 4 5% 7% 37%	75171
Transparency	Day	46% 6% 12% 21% 13% 2	74295
	Night	48% 6% 11% 21% 13% 1	74998
Seeing	Day	24% 15% 32% 21% 7% 1	14730
	Night	25% 15% 29% 23% 7% 1	23150

By Month

Percentage Cloud Cover NE (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	15% 10% 4 6% 6% 2 5% 4 4 7% 37%	1513
	11th to 20th	Day	21% 11% 3 6% 5% 3 4 4 3 6% 35%	1464
	21st to end	Day	13% 10% 3 6% 5% 3 4 4 4 8% 40%	1649
February	1st to 10th	Day	18% 12% 3 6% 4 3 5% 4 6% 7% 32%	1620
	11th to 20th	Day	15% 8% 3 6% 5% 3 5% 5% 6% 6% 36%	1653
	21st to end	Day	13% 10% 4 7% 6% 3 6% 5% 5% 7% 35%	1480
March	1st to 10th	Day	16% 10% 3 6% 5% 3 4 5% 5% 7% 36%	1824
	11th to 20th	Day	19% 5% 2 5% 5% 3 5% 5% 5% 6% 40%	1980
	21st to end	Day	19% 9% 3 5% 5% 3 3 3 4 6% 39%	2178
April	1st to 10th	Day	20% 10% 4 5% 5% 3 4 4 4 6% 34%	2111
	11th to 20th	Day	19% 8% 4 6% 4 3 4 4 4 7% 38%	2305
	21st to end	Day	22% 9% 3 5% 4 3 4 4 4 7% 35%	2340
May	1st to 10th	Day	22% 10% 3 5% 5% 3 4 4 5% 6% 33%	2340
	11th to 20th	Day	21% 7% 2 5% 4 2 3 4 5% 6% 40%	2301
	21st to end	Day	20% 7% 3 5% 5% 3 5% 4 6% 8% 35%	2766
June	1st to 10th	Day	23% 8% 3 6% 5% 2 4 5% 5% 8% 30%	2700
	11th to 20th	Day	19% 7% 3 5% 4 3 4 4 4 8% 38%	2700
	21st to end	Day	26% 7% 3 5% 5% 3 4 5% 5% 7% 30%	2700
July	1st to 10th	Day	19% 6% 3 5% 4 3 4 5% 5% 8% 39%	2627
	11th to 20th	Day	16% 6% 3 5% 4 3 4 4 6% 8% 40%	2520
	21st to end	Day	15% 6% 2 5% 5% 3 5% 5% 7% 9% 38%	2672
August	1st to 10th	Day	15% 6% 2 5% 4 3 4 4 6% 9% 42%	2327
	11th to 20th	Day	15% 7% 2 6% 6% 4 5% 4 6% 9% 38%	2304
	21st to end	Day	14% 5% 3 4 5% 2 3 5% 5% 9% 46%	2574
September	1st to 10th	Day	12% 5% 2 4 4 3 5% 4 4 8% 49%	2070
	11th to 20th	Day	14% 5% 2 3 4 3 4 3 4 6% 52%	1980
	21st to end	Day	18% 6% 2 4 4 3 4 5% 4 6% 43%	1980
October	1st to 10th	Day	17% 6% 3 5% 4 3 5% 4 5% 6% 42%	1914
	11th to 20th	Day	19% 6% 3 5% 4 3 4 4 4 6% 41%	1800
	21st to end	Day	23% 8% 3 4 5% 3 4 4 4 5% 38%	1796
November	1st to 10th	Day	19% 6% 3 5% 5% 2 4 4 5% 6% 42%	1671
	11th to 20th	Day	22% 5% 2 4 2 3 4 4 5% 7% 42%	1649
	21st to end	Day	20% 9% 3 6% 4 2 3 4 4 5% 40%	1520
December	1st to 10th	Day	24% 9% 2 5% 4 4 5% 4 5% 5% 34%	1459
	11th to 20th	Day	24% 10% 3 5% 4 3 4 4 4 6% 33%	1668
	21st to end	Day	26% 8% 2 6% 4 3 3 4 4 6% 35%	2431
January	1st to 10th	Night	17% 9% 3 6% 5% 3 4 4 5% 8% 36%	2649
	11th to 20th	Night	18% 12% 4 6% 6% 3 5% 4 4 7% 30%	2574
	21st to end	Night	13% 9% 3 6% 6% 3 4 5% 5% 9% 36%	2704
February	1st to 10th	Night	19% 10% 4 6% 5% 3 5% 5% 5% 7% 33%	2340
	11th to 20th	Night	15% 9% 4 6% 6% 3 4 4 5% 6% 38%	2192
	21st to end	Night	15% 10% 3 6% 6% 3 4 4 5% 6% 39%	1776
March	1st to 10th	Night	16% 10% 4 7% 6% 3 3 3 4 5% 38%	2121
	11th to 20th	Night	18% 9% 4 6% 5% 4 4 4 6% 6% 35%	1979
	21st to end	Night	18% 9% 3 6% 4 3 3 4 4 6% 39%	2178
April	1st to 10th	Night	23% 10% 3 4 5% 3 4 5% 4 6% 33%	1846
	11th to 20th	Night	21% 8% 3 6% 6% 3 3 4 5% 7% 35%	1603
	21st to end	Night	25% 9% 3 6% 5% 2 3 4 4 7% 32%	1620
May	1st to 10th	Night	23% 8% 2 6% 5% 3 5% 5% 5% 7% 30%	1620
	11th to 20th	Night	23% 7% 3 6% 5% 3 4 5% 5% 6% 32%	1593
	21st to end	Night	20% 10% 4 6% 5% 3 5% 3 5% 5% 34%	1519
June	1st to 10th	Night	25% 10% 3 6% 5% 3 4 4 6% 6% 27%	1260
	11th to 20th	Night	21% 9% 3 5% 4 2 4 4 6% 7% 36%	1260
	21st to end	Night	26% 10% 3 5% 4 3 4 3 5% 6% 30%	1260
July	1st to 10th	Night	21% 7% 3 6% 5% 2 5% 5% 6% 8% 32%	1329
	11th to 20th	Night	20% 9% 3 5% 5% 3 4 5% 6% 8% 33%	1440
	21st to end	Night	21% 7% 3 6% 5% 3 4 4 6% 7% 33%	1628
August	1st to 10th	Night	17% 7% 2 6% 4 3 5% 6% 7% 8% 36%	1612
	11th to 20th	Night	18% 7% 3 6% 5% 3 5% 6% 5% 9% 32%	1596
	21st to end	Night	15% 6% 2 4 5% 3 3 4 5% 9% 43%	1782
September	1st to 10th	Night	14% 5% 2 4 4 2 4 4 6% 7% 48%	1887
	11th to 20th	Night	17% 6% 2 4 4 2 3 4 4 7% 48%	1980
	21st to end	Night	18% 6% 2 4 3 2 4 4 4 8% 45%	1980
October	1st to 10th	Night	20% 6% 2 4 5% 3 4 4 5% 7% 40%	2045
	11th to 20th	Night	19% 6% 2 5% 5% 2 4 4 4 6% 41%	2160
	21st to end	Night	24% 8% 3 5% 4 3 3 4 4 6% 36%	2556
November	1st to 10th	Night	18% 6% 2 4 4 3 5% 5% 5% 6% 42%	2407
	11th to 20th	Night	19% 7% 2 4 5% 3 5% 4 5% 6% 41%	2529
	21st to end	Night	18% 8% 3 5% 4 2 4 5% 5% 6% 39%	2660
December	1st to 10th	Night	24% 9% 3 6% 4 3 4 4 5% 6% 32%	2719
	11th to 20th	Night	24% 8% 2 5% 4 2 3 4 4 7% 37%	3531
	21st to end	Night	25% 9% 3 5% 4 2 3 3 4 6% 36%	5236

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	49% 6% 11% 20% 12% 1	1514
	11th to 20th	Day	53% 6% 12% 19% 8% 2	1464
	21st to end	Day	46% 4 12% 23% 14% 1	1649
February	1st to 10th	Day	53% 5% 13% 17% 10% 2	1620
	11th to 20th	Day	49% 6% 13% 19% 12% 1	1661
	21st to end	Day	49% 5% 11% 21% 10% 4	1480
March	1st to 10th	Day	47% 6% 14% 17% 14% 2	1828
	11th to 20th	Day	43% 6% 11% 21% 16% 3	1980
	21st to end	Day	48% 5% 10% 17% 16% 5%	2178
April	1st to 10th	Day	50% 5% 10% 17% 15% 3	2111
	11th to 20th	Day	45% 6% 10% 22% 14% 3	2305
	21st to end	Day	49% 6% 9% 17% 16% 3	2340
May	1st to 10th	Day	51% 6% 9% 19% 13% 2	2340
	11th to 20th	Day	44% 5% 10% 23% 15% 2	2305
	21st to end	Day	49% 7% 11% 21% 11% 1	2766
June	1st to 10th	Day	52% 7% 12% 20% 9%	2700
	11th to 20th	Day	46% 6% 11% 19% 15% 3	2700
	21st to end	Day	54% 7% 11% 16% 10% 2	2700
July	1st to 10th	Day	44% 8% 14% 22% 12%	2556
	11th to 20th	Day	42% 8% 14% 23% 11% 1	2445
	21st to end	Day	41% 9% 15% 24% 9% 1	2523
August	1st to 10th	Day	39% 8% 16% 27% 9%	2314
	11th to 20th	Day	43% 7% 14% 23% 12%	2304
	21st to end	Day	35% 7% 14% 26% 17% 1	2574
September	1st to 10th	Day	34% 7% 13% 27% 18% 2	2070
	11th to 20th	Day	34% 6% 12% 26% 20% 3	1980
	21st to end	Day	42% 6% 9% 26% 16% 1	1980
October	1st to 10th	Day	41% 7% 11% 24% 16% 2	1914
	11th to 20th	Day	43% 5% 14% 28% 10%	1800
	21st to end	Day	48% 5% 12% 21% 13% 1	1796
November	1st to 10th	Day	44% 5% 14% 23% 13% 1	1671
	11th to 20th	Day	42% 7% 9% 21% 18% 3	1649
	21st to end	Day	47% 5% 16% 22% 8% 1	1520
December	1st to 10th	Day	53% 6% 12% 20% 8% 1	1459
	11th to 20th	Day	54% 4 10% 21% 10% 1	1668
	21st to end	Day	52% 6% 12% 18% 8% 3	2431
January	1st to 10th	Night	49% 5% 14% 22% 9% 1	2649
	11th to 20th	Night	55% 7% 11% 18% 8% 1	2574
	21st to end	Night	46% 5% 13% 23% 11% 1	2704
February	1st to 10th	Night	53% 5% 12% 17% 11% 2	2340
	11th to 20th	Night	48% 6% 11% 19% 14% 2	2195
	21st to end	Night	48% 4 10% 21% 14% 3	1776
March	1st to 10th	Night	49% 4 9% 19% 16% 3	2130
	11th to 20th	Night	49% 6% 11% 15% 16% 2	1980
	21st to end	Night	47% 4 8% 20% 18% 3	2178
April	1st to 10th	Night	52% 5% 10% 13% 16% 4	1846
	11th to 20th	Night	49% 5% 8% 20% 16% 2	1603
	21st to end	Night	53% 5% 10% 16% 13% 3	1620
May	1st to 10th	Night	52% 6% 9% 18% 14% 1	1620
	11th to 20th	Night	52% 6% 9% 19% 11% 2	1594
	21st to end	Night	52% 6% 9% 19% 13% 1	1520
June	1st to 10th	Night	56% 7% 9% 18% 7% 1	1260
	11th to 20th	Night	48% 7% 11% 21% 11% 2	1260
	21st to end	Night	56% 6% 9% 19% 9% 2	1260
July	1st to 10th	Night	51% 7% 12% 19% 11%	1291
	11th to 20th	Night	48% 8% 13% 20% 11%	1392
	21st to end	Night	50% 7% 13% 20% 9% 2	1537
August	1st to 10th	Night	45% 9% 13% 25% 9%	1600
	11th to 20th	Night	48% 9% 13% 20% 10%	1596
	21st to end	Night	40% 6% 11% 23% 19% 1	1782
September	1st to 10th	Night	36% 6% 13% 28% 16% 1	1887
	11th to 20th	Night	38% 5% 11% 25% 19% 2	1980
	21st to end	Night	39% 4 10% 28% 17% 1	1980
October	1st to 10th	Night	44% 5% 12% 23% 14% 2	2045
	11th to 20th	Night	43% 5% 12% 26% 13% 1	2160
	21st to end	Night	50% 4 11% 21% 13% 1	2556
November	1st to 10th	Night	44% 5% 12% 24% 14% 1	2407
	11th to 20th	Night	45% 5% 11% 22% 15% 2	2529
	21st to end	Night	45% 6% 14% 20% 13% 2	2660
December	1st to 10th	Night	55% 5% 11% 19% 10%	2719
	11th to 20th	Night	49% 5% 12% 21% 13% 1	3532
	21st to end	Night	51% 6% 13% 17% 11% 2	5236

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	26% 28% 29% 13% 3	180
	11th to 20th	Day	30% 23% 34% 11% 2 1	166
	21st to end	Day	18% 25% 35% 18% 3	241
February	1st to 10th	Day	27% 26% 31% 15% 1	340
	11th to 20th	Day	27% 30% 32% 10% 2	372
	21st to end	Day	22% 25% 35% 16% 2	346
March	1st to 10th	Day	25% 25% 35% 14% 2	420
	11th to 20th	Day	23% 25% 33% 15% 4	420
	21st to end	Day	25% 25% 28% 16% 6% 1	462
April	1st to 10th	Day	29% 23% 31% 13% 3 1	420
	11th to 20th	Day	26% 18% 37% 13% 5% 1	412
	21st to end	Day	27% 16% 34% 17% 5% 1	420
May	1st to 10th	Day	27% 20% 33% 15% 4 1	423
	11th to 20th	Day	18% 19% 37% 21% 4	447
	21st to end	Day	26% 12% 35% 18% 8% 1	593
June	1st to 10th	Day	26% 8% 33% 24% 8% 1	630
	11th to 20th	Day	25% 8% 30% 24% 11% 1	630
	21st to end	Day	30% 6% 28% 26% 9% 1	630
July	1st to 10th	Day	23% 7% 34% 23% 12% 1	551
	11th to 20th	Day	20% 4 33% 30% 11% 1	444
	21st to end	Day	16% 6% 37% 31% 10% 1	488
August	1st to 10th	Day	15% 7% 31% 33% 12% 1	446
	11th to 20th	Day	20% 6% 31% 28% 12% 3	439
	21st to end	Day	18% 8% 28% 32% 12% 2	495
September	1st to 10th	Day	18% 5% 33% 33% 10% 2	450
	11th to 20th	Day	21% 10% 31% 23% 10% 5%	450
	21st to end	Day	19% 10% 35% 23% 10% 4	450
October	1st to 10th	Day	18% 15% 27% 27% 11% 1	417
	11th to 20th	Day	19% 17% 31% 23% 8% 2	360
	21st to end	Day	31% 14% 32% 18% 5% 1	396
November	1st to 10th	Day	23% 21% 27% 21% 7% 1	365
	11th to 20th	Day	25% 24% 30% 17% 4 1	370
	21st to end	Day	28% 25% 27% 17% 3	370
December	1st to 10th	Day	28% 20% 33% 16% 3	309
	11th to 20th	Day	34% 28% 28% 8% 1	180
	21st to end	Day	32% 29% 21% 14% 4	198
January	1st to 10th	Night	23% 25% 31% 18% 2	760
	11th to 20th	Night	28% 24% 32% 14% 3	736
	21st to end	Night	19% 29% 32% 16% 3	792
February	1st to 10th	Night	26% 24% 34% 13% 3	720
	11th to 20th	Night	24% 29% 30% 14% 2 1	703
	21st to end	Night	22% 22% 33% 19% 4	592
March	1st to 10th	Night	23% 21% 36% 18% 2	720
	11th to 20th	Night	23% 19% 32% 20% 6%	720
	21st to end	Night	23% 17% 33% 19% 6% 1	792
April	1st to 10th	Night	31% 15% 33% 18% 3	720
	11th to 20th	Night	26% 10% 34% 25% 4	539
	21st to end	Night	32% 10% 28% 22% 8% 1	540
May	1st to 10th	Night	27% 8% 31% 26% 7% 1	540
	11th to 20th	Night	25% 9% 35% 25% 6%	532
	21st to end	Night	26% 6% 26% 31% 10% 1	469
June	1st to 10th	Night	33% 5% 23% 29% 9% 1	360
	11th to 20th	Night	26% 4 26% 31% 12% 1	360
	21st to end	Night	34% 2 19% 34% 10% 1	360
July	1st to 10th	Night	25% 3 25% 35% 11%	350
	11th to 20th	Night	24% 3 22% 36% 14% 1	348
	21st to end	Night	25% 2 21% 38% 13% 1	448
August	1st to 10th	Night	23% 3 22% 37% 14% 1	538
	11th to 20th	Night	22% 3 21% 39% 14% 1	532
	21st to end	Night	19% 4 23% 36% 18% 2	594
September	1st to 10th	Night	17% 3 28% 34% 15% 2	699
	11th to 20th	Night	21% 7% 26% 28% 15% 4	720
	21st to end	Night	20% 7% 30% 28% 13% 2	720
October	1st to 10th	Night	23% 9% 26% 26% 15% 1	720
	11th to 20th	Night	22% 14% 28% 23% 12% 1	720
	21st to end	Night	29% 17% 29% 20% 5% 1	792
November	1st to 10th	Night	23% 15% 29% 24% 8% 1	740
	11th to 20th	Night	23% 24% 27% 19% 6% 1	789
	21st to end	Night	25% 23% 30% 16% 6%	850
December	1st to 10th	Night	31% 19% 33% 14% 3	850
	11th to 20th	Night	28% 26% 29% 15% 2	850
	21st to end	Night	30% 22% 30% 15% 3	935

Page generated at 2024-01-11 13:32:01. Version ac07

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