Lake City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake City clear sky chart from 2005-11-06 to 2024-05-14.

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	10% 6% 2 6% 5% 5% 5% 5% 6% 8% 40%	84000
	Night	10% 6% 2 6% 4 4 5% 4 6% 8% 43%	85514
Transparency	Day	40% 5% 14% 19% 15% 7%	83723
	Night	38% 5% 14% 19% 16% 8%	85310
Seeing	Day	11% 5% 17% 25% 24% 18%	14598
	Night	12% 3 18% 35% 26% 6%	24724

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% 4 3 4 3 4 7% 46%	2836
	11th to 20th	Day	16% 8% 3 6% 5% 5% 4 2 4 7% 39%	2840
	21st to end	Day	11% 6% 3 6% 4 4 5% 3 6% 7% 45%	3266
February	1st to 10th	Day	15% 8% 3 5% 4 3 3 3 5% 7% 44%	1900
	11th to 20th	Day	13% 6% 2 6% 3 4 4 4 5% 6% 47%	1848
	21st to end	Day	13% 7% 2 6% 4 3 3 3 5% 6% 48%	1572
March	1st to 10th	Day	14% 7% 3 6% 4 4 5% 5% 6% 9% 36%	3435
	11th to 20th	Day	8% 4 2 5% 4 5% 5% 4 6% 8% 50%	3480
	21st to end	Day	14% 4 2 4 4 3 4 4 5% 8% 47%	3815
April	1st to 10th	Day	8% 5% 2 6% 4 4 4 5% 6% 8% 47%	2090
	11th to 20th	Day	9% 5% 2 7% 5% 4 4 4 6% 7% 45%	2066
	21st to end	Day	5% 4 1 4 4 4 5% 4 7% 7% 54%	2422
May	1st to 10th	Day	5% 4 1 4 4 4 4 4 5% 9% 56%	2470
	11th to 20th	Day	7% 5% 2 7% 6% 5% 6% 6% 8% 10% 40%	2340
	21st to end	Day	8% 6% 2 6% 6% 6% 6% 5% 7% 8% 40%	2531
June	1st to 10th	Day	11% 6% 3 9% 7% 6% 7% 6% 8% 10% 29%	2340
	11th to 20th	Day	5% 6% 2 7% 8% 7% 9% 7% 9% 11% 30%	2340
	21st to end	Day	9% 6% 2 7% 7% 7% 7% 6% 8% 10% 30%	2340
July	1st to 10th	Day	7% 5% 3 8% 7% 6% 8% 6% 10% 11% 28%	2340
	11th to 20th	Day	8% 6% 3 9% 8% 8% 8% 7% 9% 10% 24%	2340
	21st to end	Day	7% 7% 3 8% 8% 7% 8% 6% 8% 11% 27%	2547
August	1st to 10th	Day	10% 6% 2 8% 7% 7% 7% 6% 8% 12% 26%	2327
	11th to 20th	Day	11% 8% 3 8% 8% 7% 9% 6% 9% 11% 20%	2180
	21st to end	Day	12% 7% 3 10% 7% 8% 6% 6% 9% 9% 24%	2234
September	1st to 10th	Day	9% 7% 4 9% 8% 8% 7% 6% 7% 11% 24%	1980
	11th to 20th	Day	10% 7% 3 9% 7% 7% 8% 5% 8% 9% 26%	1980
	21st to end	Day	9% 8% 3 7% 6% 6% 5% 5% 6% 7% 38%	1980
October	1st to 10th	Day	11% 7% 3 7% 4 5% 5% 4 6% 7% 41%	1980
	11th to 20th	Day	7% 4 2 5% 4 4 4 3 6% 7% 54%	1832
	21st to end	Day	8% 5% 2 5% 4 4 4 5% 5% 7% 51%	1980
November	1st to 10th	Day	9% 4 2 4 4 3 4 4 6% 7% 52%	1857
	11th to 20th	Day	9% 6% 3 5% 4 3 4 3 5% 6% 51%	1815
	21st to end	Day	11% 6% 2 4 4 4 5% 4 6% 6% 48%	1710
December	1st to 10th	Day	9% 6% 3 7% 5% 4 4 4 5% 8% 46%	1710
	11th to 20th	Day	15% 7% 2 7% 4 3 4 3 5% 6% 45%	2153
	21st to end	Day	17% 8% 3 7% 4 4 3 3 4 5% 41%	3124
January	1st to 10th	Night	14% 9% 3 5% 3 3 4 3 5% 7% 44%	4109
	11th to 20th	Night	11% 8% 3 8% 5% 4 5% 4 6% 7% 40%	4120
	21st to end	Night	14% 8% 2 7% 4 4 4 3 6% 7% 41%	4372
February	1st to 10th	Night	14% 6% 2 6% 4 3 4 3 4 6% 47%	2280
	11th to 20th	Night	13% 7% 2 5% 4 4 4 2 4 7% 48%	2218
	21st to end	Night	12% 8% 2 6% 4 3 4 2 4 6% 48%	1879
March	1st to 10th	Night	16% 9% 3 8% 5% 4 4 4 5% 7% 35%	3418
	11th to 20th	Night	9% 5% 2 5% 4 3 4 3 7% 10% 47%	3480
	21st to end	Night	13% 6% 2 5% 4 4 4 3 5% 7% 48%	3817
April	1st to 10th	Night	10% 5% 2 4 4 4 4 4 5% 8% 49%	2090
	11th to 20th	Night	8% 6% 2 6% 4 4 4 3 6% 7% 51%	2063
	21st to end	Night	5% 5% 1 5% 3 3 4 3 7% 6% 57%	1772
May	1st to 10th	Night	5% 4 1 4 3 3 4 4 5% 8% 60%	1710
	11th to 20th	Night	5% 5% 2 5% 4 5% 5% 5% 7% 11% 47%	1625
	21st to end	Night	6% 4 2 5% 4 4 5% 5% 6% 9% 49%	1744
June	1st to 10th	Night	10% 6% 2 7% 6% 5% 6% 5% 8% 11% 34%	1620
	11th to 20th	Night	5% 4 2 6% 5% 6% 7% 5% 10% 13% 37%	1620
	21st to end	Night	8% 4 2 7% 5% 6% 7% 5% 8% 14% 35%	1620
July	1st to 10th	Night	6% 5% 2 6% 6% 6% 7% 6% 9% 13% 33%	1620
	11th to 20th	Night	4 6% 2 7% 6% 7% 6% 7% 10% 12% 32%	1620
	21st to end	Night	5% 5% 2 7% 5% 5% 6% 6% 10% 12% 37%	1771
August	1st to 10th	Night	7% 4 2 7% 5% 5% 6% 5% 9% 14% 35%	1611
	11th to 20th	Night	6% 4 2 6% 5% 5% 7% 7% 10% 16% 32%	1715
	21st to end	Night	10% 7% 4 7% 6% 6% 7% 6% 7% 9% 32%	2101
September	1st to 10th	Night	8% 7% 3 9% 6% 6% 7% 5% 9% 10% 29%	1980
	11th to 20th	Night	10% 6% 3 7% 6% 6% 6% 6% 8% 11% 30%	1980
	21st to end	Night	8% 5% 3 8% 5% 5% 5% 5% 7% 9% 41%	1980
October	1st to 10th	Night	8% 6% 3 7% 5% 5% 4 3 6% 8% 46%	1980
	11th to 20th	Night	7% 3 1 5% 4 4 4 3 6% 6% 57%	2128
	21st to end	Night	7% 5% 2 6% 5% 4 4 3 6% 6% 51%	2376
November	1st to 10th	Night	8% 4 2 5% 4 4 3 4 7% 7% 52%	2221
	11th to 20th	Night	10% 5% 2 6% 4 3 4 3 5% 6% 52%	2360
	21st to end	Night	11% 6% 2 6% 5% 4 3 4 6% 7% 47%	2470
December	1st to 10th	Night	11% 6% 3 6% 4 3 3 3 6% 8% 46%	2470
	11th to 20th	Night	14% 6% 2 5% 3 3 4 3 5% 6% 48%	3042
	21st to end	Night	16% 8% 3 6% 4 4 4 3 6% 6% 40%	4532

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	39% 2 6% 18% 21% 14%	2837
	11th to 20th	Day	47% 2 5% 15% 16% 14%	2840
	21st to end	Day	39% 2 10% 18% 18% 13%	3266
February	1st to 10th	Day	41% 2 10% 15% 20% 11%	1900
	11th to 20th	Day	39% 3 7% 16% 23% 13%	1858
	21st to end	Day	38% 3 8% 16% 21% 14%	1572
March	1st to 10th	Day	44% 3 10% 21% 15% 7%	3435
	11th to 20th	Day	32% 3 15% 17% 20% 13%	3480
	21st to end	Day	35% 2 9% 28% 16% 9%	3815
April	1st to 10th	Day	33% 4 12% 18% 19% 13%	2090
	11th to 20th	Day	37% 3 8% 22% 20% 9%	2066
	21st to end	Day	27% 4 10% 24% 25% 9%	2422
May	1st to 10th	Day	26% 4 11% 25% 25% 10%	2470
	11th to 20th	Day	36% 5% 17% 22% 17% 3	2344
	21st to end	Day	38% 5% 12% 24% 18% 3	2531
June	1st to 10th	Day	48% 6% 18% 17% 10% 1	2340
	11th to 20th	Day	44% 7% 22% 21% 6%	2340
	21st to end	Day	46% 8% 24% 15% 6% 1	2340
July	1st to 10th	Day	44% 11% 28% 16% 1	2275
	11th to 20th	Day	49% 11% 27% 10% 3	2271
	21st to end	Day	46% 8% 26% 17% 3	2405
August	1st to 10th	Day	47% 9% 27% 15% 2	2314
	11th to 20th	Day	53% 9% 26% 10% 1	2180
	21st to end	Day	52% 9% 22% 13% 3	2234
September	1st to 10th	Day	51% 8% 19% 13% 6% 2	1980
	11th to 20th	Day	50% 8% 17% 15% 7% 1	1980
	21st to end	Day	43% 6% 12% 19% 17% 4	1980
October	1st to 10th	Day	41% 4 9% 18% 17% 11%	1980
	11th to 20th	Day	29% 3 8% 22% 30% 9%	1832
	21st to end	Day	32% 4 9% 16% 25% 15%	1980
November	1st to 10th	Day	31% 3 10% 21% 19% 15%	1857
	11th to 20th	Day	34% 3 8% 19% 24% 11%	1815
	21st to end	Day	36% 3 9% 21% 24% 8%	1710
December	1st to 10th	Day	36% 3 13% 24% 18% 7%	1710
	11th to 20th	Day	41% 3 7% 20% 20% 9%	2150
	21st to end	Day	47% 3 5% 19% 19% 8%	3124
January	1st to 10th	Night	41% 2 7% 14% 20% 15%	4109
	11th to 20th	Night	44% 2 7% 16% 21% 11%	4120
	21st to end	Night	43% 3 11% 14% 18% 10%	4372
February	1st to 10th	Night	39% 3 8% 16% 19% 14%	2280
	11th to 20th	Night	38% 3 7% 19% 19% 14%	2219
	21st to end	Night	39% 3 8% 19% 19% 13%	1879
March	1st to 10th	Night	49% 3 11% 16% 12% 7%	3418
	11th to 20th	Night	32% 3 16% 20% 18% 11%	3480
	21st to end	Night	37% 2 10% 21% 20% 10%	3817
April	1st to 10th	Night	33% 4 13% 19% 19% 11%	2090
	11th to 20th	Night	34% 4 9% 23% 21% 10%	2063
	21st to end	Night	26% 3 13% 28% 21% 8%	1772
May	1st to 10th	Night	23% 5% 13% 28% 22% 9%	1710
	11th to 20th	Night	30% 6% 22% 23% 14% 4	1626
	21st to end	Night	29% 7% 17% 24% 21% 3	1745
June	1st to 10th	Night	42% 7% 21% 22% 8% 1	1620
	11th to 20th	Night	33% 11% 26% 24% 6%	1620
	21st to end	Night	37% 11% 26% 19% 6% 1	1620
July	1st to 10th	Night	40% 12% 28% 17% 3	1575
	11th to 20th	Night	40% 12% 31% 14% 4	1566
	21st to end	Night	33% 13% 32% 18% 4	1672
August	1st to 10th	Night	35% 12% 34% 16% 3	1600
	11th to 20th	Night	35% 13% 36% 13% 2	1715
	21st to end	Night	46% 10% 23% 17% 4	2101
September	1st to 10th	Night	46% 10% 22% 15% 6% 1	1980
	11th to 20th	Night	46% 10% 19% 17% 7% 1	1980
	21st to end	Night	38% 6% 19% 18% 15% 4	1980
October	1st to 10th	Night	36% 5% 13% 20% 15% 12%	1980
	11th to 20th	Night	27% 4 7% 26% 28% 7%	2128
	21st to end	Night	31% 5% 9% 17% 23% 14%	2376
November	1st to 10th	Night	30% 4 9% 24% 19% 14%	2221
	11th to 20th	Night	34% 3 8% 19% 23% 13%	2360
	21st to end	Night	37% 4 9% 21% 20% 10%	2470
December	1st to 10th	Night	37% 2 13% 24% 16% 7%	2470
	11th to 20th	Night	38% 3 10% 17% 22% 9%	3044
	21st to end	Night	45% 3 9% 19% 19% 5%	4532

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	11% 12% 44% 22% 10% 1	270
	11th to 20th	Day	13% 9% 34% 28% 13% 3	270
	21st to end	Day	16% 13% 46% 20% 5%	297
February	1st to 10th	Day	17% 13% 34% 23% 10% 2	270
	11th to 20th	Day	19% 7% 38% 25% 10% 1	270
	21st to end	Day	10% 11% 38% 29% 11% 1	227
March	1st to 10th	Day	13% 8% 32% 30% 16% 1	460
	11th to 20th	Day	15% 5% 30% 32% 15% 3	460
	21st to end	Day	13% 7% 31% 27% 20% 2	506
April	1st to 10th	Day	10% 9% 29% 29% 19% 4	460
	11th to 20th	Day	11% 6% 29% 30% 18% 6%	452
	21st to end	Day	7% 4 21% 36% 22% 11%	460
May	1st to 10th	Day	7% 5% 17% 32% 25% 15%	463
	11th to 20th	Day	7% 2 12% 27% 31% 21%	459
	21st to end	Day	11% 1 7% 17% 33% 30%	485
June	1st to 10th	Day	14% 2 7% 21% 28% 29%	450
	11th to 20th	Day	8% 1 7% 18% 29% 37%	450
	21st to end	Day	8% 2 2 18% 30% 41%	450
July	1st to 10th	Day	7% 2 2 11% 29% 49%	445
	11th to 20th	Day	7% 1 1 11% 33% 46%	444
	21st to end	Day	9% 2 3 12% 34% 39%	488
August	1st to 10th	Day	12% 2 2 14% 29% 41%	446
	11th to 20th	Day	8% 1 2 11% 29% 49%	439
	21st to end	Day	12% 2 1 16% 33% 36%	495
September	1st to 10th	Day	11% 3 4 17% 32% 34%	450
	11th to 20th	Day	14% 2 4 27% 33% 20%	450
	21st to end	Day	11% 2 5% 22% 38% 22%	450
October	1st to 10th	Day	14% 4 16% 33% 21% 12%	450
	11th to 20th	Day	7% 3 14% 31% 33% 12%	450
	21st to end	Day	10% 3 17% 38% 26% 6%	495
November	1st to 10th	Day	13% 4 19% 34% 23% 7%	455
	11th to 20th	Day	16% 4 26% 35% 15% 4	375
	21st to end	Day	11% 6% 31% 34% 16% 2	270
December	1st to 10th	Day	11% 8% 31% 26% 20% 5%	270
	11th to 20th	Day	18% 6% 31% 31% 13% 1	270
	21st to end	Day	16% 7% 28% 33% 12% 3	297
January	1st to 10th	Night	17% 6% 31% 36% 9% 1	760
	11th to 20th	Night	13% 8% 26% 38% 16% 1	760
	21st to end	Night	19% 7% 32% 34% 8%	836
February	1st to 10th	Night	17% 5% 29% 37% 11% 1	760
	11th to 20th	Night	16% 6% 31% 38% 8%	743
	21st to end	Night	15% 6% 29% 44% 6%	628
March	1st to 10th	Night	11% 6% 31% 40% 12%	760
	11th to 20th	Night	12% 6% 28% 38% 15% 1	760
	21st to end	Night	12% 5% 30% 39% 14% 1	836
April	1st to 10th	Night	12% 5% 29% 39% 15% 1	760
	11th to 20th	Night	11% 5% 28% 39% 17% 1	751
	21st to end	Night	7% 3 21% 43% 25% 1	622
May	1st to 10th	Night	6% 3 15% 48% 24% 2	570
	11th to 20th	Night	7% 1 14% 43% 30% 5%	542
	21st to end	Night	8% 2 7% 36% 41% 6%	584
June	1st to 10th	Night	11% 1 6% 34% 41% 7%	540
	11th to 20th	Night	5% 2 4 29% 43% 17%	540
	21st to end	Night	9% 1 4 21% 47% 18%	540
July	1st to 10th	Night	7% 1 2 19% 51% 20%	525
	11th to 20th	Night	7% 1 1 12% 52% 27%	522
	21st to end	Night	6% 2 1 18% 55% 19%	591
August	1st to 10th	Night	8% 1 1 14% 57% 19%	537
	11th to 20th	Night	6% 2 1 12% 54% 24%	534
	21st to end	Night	12% 2 3 22% 43% 17%	715
September	1st to 10th	Night	12% 2 3 22% 47% 14%	720
	11th to 20th	Night	13% 2 5% 31% 40% 8%	720
	21st to end	Night	11% 1 8% 34% 39% 7%	720
October	1st to 10th	Night	12% 1 15% 39% 29% 3	720
	11th to 20th	Night	9% 2 15% 41% 31% 2	720
	21st to end	Night	8% 2 19% 42% 26% 2	792
November	1st to 10th	Night	10% 2 24% 41% 21% 1	740
	11th to 20th	Night	13% 3 22% 44% 17% 1	760
	21st to end	Night	14% 3 25% 43% 15% 1	760
December	1st to 10th	Night	15% 3 24% 37% 20% 2	760
	11th to 20th	Night	14% 4 26% 38% 17% 1	760
	21st to end	Night	16% 5% 25% 39% 15%	836

Page generated at 2024-05-11 05:13:34. Version ac07

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