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 2026-02-16.

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	3 6% 4 9% 5% 5% 5% 4 5% 7% 47%	139736
	Night	1 3 2 6% 4 4 4 4 6% 8% 58%	138638
Transparency	Day	36% 5% 8% 20% 22% 9%	134645
	Night	23% 5% 11% 25% 26% 10%	134735
Seeing	Day	16% 22% 26% 22% 11% 3	16980
	Night	6% 13% 29% 32% 18% 3	27234

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	3 3 15% 8% 4 3 3 5% 7% 48%	5076
	11th to 20th	Day	2 3 9% 4 6% 4 2 4 6% 59%	5340
	21st to end	Day	5% 4 10% 5% 5% 3 3 5% 6% 54%	5844
February	1st to 10th	Day	4 4 13% 5% 4 4 3 6% 8% 49%	1890
	11th to 20th	Day	5% 4 10% 7% 6% 4 4 6% 8% 46%	1870
	21st to end	Day	4 4 13% 7% 6% 4 3 5% 7% 47%	1650
March	1st to 10th	Day	6% 8% 14% 5% 4 4 3 4 5% 48%	4882
	11th to 20th	Day	1 8% 8% 17% 6% 5% 5% 4 5% 6% 35%	5000
	21st to end	Day	13% 6% 12% 6% 5% 5% 3 5% 6% 38%	5560
April	1st to 10th	Day	1 9% 4 9% 6% 5% 4 4 6% 7% 46%	2400
	11th to 20th	Day	1 11% 5% 11% 6% 5% 5% 4 5% 6% 42%	2371
	21st to end	Day	1 9% 5% 8% 6% 5% 5% 4 6% 7% 44%	2400
May	1st to 10th	Day	2 11% 4 10% 6% 6% 6% 5% 5% 7% 38%	5677
	11th to 20th	Day	2 8% 3 8% 6% 5% 5% 5% 6% 7% 44%	5992
	21st to end	Day	2 5% 2 5% 4 5% 6% 5% 7% 8% 51%	6925
June	1st to 10th	Day	4 5% 2 6% 5% 5% 5% 5% 6% 7% 49%	2800
	11th to 20th	Day	4 5% 2 7% 4 3 5% 4 5% 6% 55%	2800
	21st to end	Day	5% 6% 3 6% 6% 5% 4 4 5% 7% 49%	2800
July	1st to 10th	Day	6% 5% 2 6% 5% 5% 5% 4 5% 5% 53%	6339
	11th to 20th	Day	6% 5% 3 9% 7% 7% 8% 6% 8% 9% 32%	5934
	21st to end	Day	8% 8% 4 11% 7% 7% 7% 5% 6% 6% 32%	6401
August	1st to 10th	Day	9% 6% 3 9% 7% 7% 6% 5% 7% 8% 33%	5779
	11th to 20th	Day	9% 7% 3 10% 6% 7% 6% 4 6% 6% 36%	5562
	21st to end	Day	9% 8% 4 12% 8% 7% 6% 5% 6% 7% 28%	5984
September	1st to 10th	Day	9% 9% 3 9% 5% 6% 5% 4 5% 5% 40%	2400
	11th to 20th	Day	8% 7% 4 8% 6% 4 4 4 4 5% 47%	2400
	21st to end	Day	7% 6% 3 7% 4 4 4 3 4 5% 53%	2115
October	1st to 10th	Day	6% 7% 2 5% 3 4 3 3 3 5% 59%	3270
	11th to 20th	Day	4 8% 3 7% 5% 5% 6% 4 5% 5% 48%	3250
	21st to end	Day	1 5% 3 5% 3 3 3 2 3 4 68%	3548
November	1st to 10th	Day	1 4 2 5% 3 3 3 2 5% 5% 68%	1998
	11th to 20th	Day	4 2 5% 4 3 3 3 4 6% 67%	1890
	21st to end	Day	5% 2 9% 4 3 3 3 4 5% 62%	1691
December	1st to 10th	Day	3 2 7% 4 3 3 2 4 6% 66%	2700
	11th to 20th	Day	4 2 7% 4 3 3 3 4 6% 64%	3106
	21st to end	Day	3 3 9% 4 4 4 3 6% 9% 55%	4092
January	1st to 10th	Night	1 3 14% 8% 6% 4 4 7% 8% 45%	7901
	11th to 20th	Night	2 2 9% 4 4 2 2 4 6% 65%	7650
	21st to end	Night	2 2 7% 5% 4 4 3 5% 7% 60%	8370
February	1st to 10th	Night	2 3 8% 6% 5% 4 3 5% 7% 58%	2730
	11th to 20th	Night	3 2 7% 6% 5% 4 4 8% 8% 54%	2525
	21st to end	Night	3 3 7% 6% 6% 5% 4 5% 8% 54%	1980
March	1st to 10th	Night	3 5% 10% 4 4 3 3 5% 6% 56%	4993
	11th to 20th	Night	4 4 13% 5% 5% 5% 4 5% 7% 47%	5000
	21st to end	Night	7% 3 9% 6% 5% 5% 4 6% 8% 47%	5409
April	1st to 10th	Night	5% 2 7% 6% 4 4 3 7% 7% 56%	2000
	11th to 20th	Night	1 6% 3 8% 4 6% 4 3 5% 8% 50%	1977
	21st to end	Night	1 6% 4 7% 4 4 3 3 6% 8% 55%	2000
May	1st to 10th	Night	1 7% 4 6% 4 4 5% 5% 6% 8% 50%	4286
	11th to 20th	Night	1 4 1 4 3 4 3 3 6% 9% 61%	3919
	21st to end	Night	1 2 1 3 2 2 2 3 4 7% 73%	3972
June	1st to 10th	Night	1 2 1 3 2 3 3 3 5% 8% 67%	1600
	11th to 20th	Night	2 3 1 2 2 3 4 2 5% 6% 70%	1600
	21st to end	Night	2 3 1 3 3 4 5% 3 6% 8% 63%	1600
July	1st to 10th	Night	2 2 1 3 3 3 4 4 6% 7% 65%	3640
	11th to 20th	Night	1 2 1 4 4 4 4 5% 8% 13% 54%	4042
	21st to end	Night	2 3 1 5% 4 5% 6% 5% 8% 11% 49%	4472
August	1st to 10th	Night	3 3 1 4 4 4 5% 6% 7% 11% 53%	4033
	11th to 20th	Night	3 2 1 3 3 3 4 4 8% 13% 57%	4286
	21st to end	Night	3 4 2 8% 6% 6% 6% 5% 9% 10% 40%	4993
September	1st to 10th	Night	4 4 2 6% 4 4 4 4 7% 8% 53%	2000
	11th to 20th	Night	3 3 2 5% 3 4 5% 3 6% 8% 59%	2000
	21st to end	Night	2 4 1 4 3 3 3 3 4 7% 66%	2280
October	1st to 10th	Night	2 3 1 3 2 2 2 2 3 5% 75%	3920
	11th to 20th	Night	1 4 2 5% 3 4 5% 3 5% 7% 61%	3898
	21st to end	Night	1 4 2 4 3 2 3 2 3 5% 71%	4252
November	1st to 10th	Night	4 2 4 2 3 4 4 5% 7% 65%	2497
	11th to 20th	Night	2 1 4 3 3 3 3 4 7% 68%	2730
	21st to end	Night	1 5% 3 6% 4 4 3 4 5% 6% 60%	2924
December	1st to 10th	Night	1 1 4 3 2 3 2 4 6% 73%	4710
	11th to 20th	Night	2 2 4 3 3 3 3 5% 8% 66%	5321
	21st to end	Night	3 3 9% 5% 4 4 4 6% 7% 55%	7128

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	32% 6% 8% 25% 22% 6%	5079
	11th to 20th	Day	23% 3 10% 22% 26% 15%	5340
	21st to end	Day	30% 4 6% 23% 26% 13%	5844
February	1st to 10th	Day	32% 4 14% 22% 18% 10%	1890
	11th to 20th	Day	34% 4 10% 20% 23% 9%	1879
	21st to end	Day	35% 4 6% 19% 23% 13%	1650
March	1st to 10th	Day	39% 2 4 16% 24% 14%	4882
	11th to 20th	Day	50% 2 6% 22% 17% 3	5000
	21st to end	Day	44% 6% 9% 26% 12% 3	5560
April	1st to 10th	Day	35% 6% 10% 22% 21% 7%	2400
	11th to 20th	Day	40% 4 9% 22% 20% 5%	2374
	21st to end	Day	37% 5% 9% 30% 17% 3	2400
May	1st to 10th	Day	42% 6% 8% 21% 18% 6%	5677
	11th to 20th	Day	36% 4 6% 24% 23% 6%	5995
	21st to end	Day	29% 6% 7% 23% 31% 5%	6926
June	1st to 10th	Day	32% 5% 9% 25% 21% 8%	2800
	11th to 20th	Day	29% 4 6% 17% 26% 18%	2800
	21st to end	Day	35% 4 5% 16% 23% 17%	2800
July	1st to 10th	Day	32% 5% 5% 8% 17% 33%	6271
	11th to 20th	Day	43% 7% 14% 17% 13% 6%	5863
	21st to end	Day	48% 7% 11% 12% 15% 8%	6217
August	1st to 10th	Day	54% 8% 14% 10% 10% 4	4208
	11th to 20th	Day	48% 8% 10% 12% 18% 5%	4021
	21st to end	Day	51% 6% 9% 14% 15% 5%	4311
September	1st to 10th	Day	45% 4 8% 14% 21% 8%	2400
	11th to 20th	Day	40% 4 7% 16% 24% 9%	2400
	21st to end	Day	34% 4 5% 22% 28% 8%	2115
October	1st to 10th	Day	30% 3 4 18% 33% 12%	3270
	11th to 20th	Day	35% 4 8% 21% 26% 7%	3250
	21st to end	Day	20% 2 5% 20% 41% 11%	3548
November	1st to 10th	Day	19% 3 9% 26% 32% 10%	1998
	11th to 20th	Day	18% 3 10% 31% 29% 10%	1890
	21st to end	Day	24% 3 9% 26% 25% 13%	1691
December	1st to 10th	Day	19% 4 10% 30% 28% 9%	2700
	11th to 20th	Day	22% 4 12% 28% 29% 6%	3104
	21st to end	Day	25% 5% 9% 24% 25% 12%	4092
January	1st to 10th	Night	32% 6% 7% 28% 22% 6%	7902
	11th to 20th	Night	20% 3 11% 25% 25% 16%	7650
	21st to end	Night	23% 4 7% 23% 28% 15%	8370
February	1st to 10th	Night	25% 4 15% 24% 23% 10%	2730
	11th to 20th	Night	25% 5% 11% 25% 25% 9%	2526
	21st to end	Night	25% 4 8% 24% 28% 11%	1980
March	1st to 10th	Night	28% 4 6% 18% 36% 10%	4993
	11th to 20th	Night	36% 3 8% 22% 25% 6%	5000
	21st to end	Night	33% 5% 13% 34% 13% 2	5409
April	1st to 10th	Night	24% 5% 15% 27% 22% 6%	2000
	11th to 20th	Night	29% 6% 11% 27% 24% 4	1977
	21st to end	Night	26% 4 13% 33% 22% 2	2000
May	1st to 10th	Night	28% 7% 10% 27% 26% 2	4283
	11th to 20th	Night	20% 4 9% 38% 28% 2	3920
	21st to end	Night	13% 3 8% 29% 39% 8%	3972
June	1st to 10th	Night	15% 4 13% 30% 30% 8%	1600
	11th to 20th	Night	16% 3 9% 21% 33% 20%	1600
	21st to end	Night	18% 4 9% 23% 28% 18%	1600
July	1st to 10th	Night	18% 5% 10% 12% 17% 37%	3600
	11th to 20th	Night	19% 8% 19% 31% 15% 8%	3990
	21st to end	Night	26% 8% 22% 20% 15% 8%	4344
August	1st to 10th	Night	32% 13% 23% 14% 13% 5%	2928
	11th to 20th	Night	22% 11% 25% 14% 22% 7%	3103
	21st to end	Night	35% 8% 15% 20% 18% 5%	3597
September	1st to 10th	Night	27% 7% 13% 21% 25% 8%	2000
	11th to 20th	Night	22% 6% 13% 21% 29% 9%	2000
	21st to end	Night	20% 4 6% 32% 32% 7%	2280
October	1st to 10th	Night	15% 2 6% 23% 41% 13%	3920
	11th to 20th	Night	21% 4 9% 33% 26% 7%	3898
	21st to end	Night	16% 3 6% 23% 41% 11%	4252
November	1st to 10th	Night	18% 4 11% 27% 31% 10%	2497
	11th to 20th	Night	14% 3 10% 31% 32% 10%	2730
	21st to end	Night	23% 5% 8% 26% 26% 12%	2924
December	1st to 10th	Night	15% 3 11% 33% 31% 8%	4710
	11th to 20th	Night	17% 4 9% 29% 33% 8%	5322
	21st to end	Night	27% 6% 9% 22% 25% 11%	7128

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	19% 21% 32% 20% 7% 1	330
	11th to 20th	Day	17% 30% 23% 24% 6%	330
	21st to end	Day	11% 26% 33% 23% 7% 1	363
February	1st to 10th	Day	21% 31% 32% 15% 2 1	330
	11th to 20th	Day	19% 36% 26% 13% 5%	315
	21st to end	Day	26% 33% 20% 18% 3	249
March	1st to 10th	Day	22% 34% 23% 17% 4	465
	11th to 20th	Day	21% 27% 27% 18% 5% 1	500
	21st to end	Day	25% 33% 27% 12% 2	550
April	1st to 10th	Day	21% 30% 30% 15% 4 1	500
	11th to 20th	Day	28% 34% 25% 9% 3 1	492
	21st to end	Day	19% 34% 28% 14% 4 1	500
May	1st to 10th	Day	20% 34% 31% 10% 5%	503
	11th to 20th	Day	14% 29% 31% 16% 7% 2	588
	21st to end	Day	16% 25% 25% 20% 11% 3	789
June	1st to 10th	Day	10% 15% 28% 26% 17% 4	730
	11th to 20th	Day	9% 20% 29% 25% 13% 4	730
	21st to end	Day	7% 18% 27% 25% 18% 5%	730
July	1st to 10th	Day	9% 9% 20% 33% 21% 7%	721
	11th to 20th	Day	14% 7% 18% 32% 21% 7%	550
	21st to end	Day	15% 10% 18% 30% 20% 7%	575
August	1st to 10th	Day	19% 11% 21% 27% 16% 6%	527
	11th to 20th	Day	12% 11% 23% 32% 16% 6%	517
	21st to end	Day	16% 10% 26% 29% 16% 4	583
September	1st to 10th	Day	15% 11% 24% 27% 16% 6%	530
	11th to 20th	Day	16% 17% 32% 22% 10% 3	530
	21st to end	Day	14% 20% 26% 21% 13% 6%	417
October	1st to 10th	Day	19% 19% 19% 21% 17% 5%	330
	11th to 20th	Day	19% 23% 24% 20% 12% 2	330
	21st to end	Day	16% 23% 26% 23% 11% 1	363
November	1st to 10th	Day	16% 26% 26% 21% 9% 2	330
	11th to 20th	Day	13% 25% 28% 22% 10% 1	330
	21st to end	Day	12% 26% 30% 20% 11% 2	330
December	1st to 10th	Day	16% 22% 30% 21% 9% 2	330
	11th to 20th	Day	17% 24% 29% 21% 8% 1	330
	21st to end	Day	21% 28% 25% 19% 6% 1	363
January	1st to 10th	Night	6% 14% 35% 30% 13% 2	945
	11th to 20th	Night	6% 14% 36% 30% 12% 1	840
	21st to end	Night	2 15% 37% 34% 9% 4	924
February	1st to 10th	Night	6% 17% 39% 30% 7%	840
	11th to 20th	Night	5% 18% 41% 28% 8%	804
	21st to end	Night	8% 15% 43% 28% 4	660
March	1st to 10th	Night	8% 20% 34% 29% 9% 2	800
	11th to 20th	Night	6% 14% 35% 31% 14% 1	800
	21st to end	Night	7% 18% 39% 29% 7% 1	851
April	1st to 10th	Night	6% 24% 36% 28% 6%	600
	11th to 20th	Night	9% 21% 34% 26% 9%	593
	21st to end	Night	6% 19% 35% 28% 11% 2	600
May	1st to 10th	Night	7% 14% 34% 34% 11% 1	600
	11th to 20th	Night	8% 11% 26% 34% 18% 3	591
	21st to end	Night	8% 15% 28% 28% 20% 2	650
June	1st to 10th	Night	3 9% 23% 39% 26% 1	600
	11th to 20th	Night	6% 12% 23% 38% 20% 3	600
	21st to end	Night	2 7% 19% 41% 29% 3	600
July	1st to 10th	Night	5% 3 12% 39% 39% 3	585
	11th to 20th	Night	3 3 8% 31% 47% 9%	582
	21st to end	Night	6% 2 7% 30% 47% 8%	657
August	1st to 10th	Night	5% 4 9% 32% 45% 6%	597
	11th to 20th	Night	8% 2 8% 37% 40% 5%	594
	21st to end	Night	6% 5% 8% 35% 40% 5%	660
September	1st to 10th	Night	5% 4 13% 39% 36% 4	600
	11th to 20th	Night	5% 8% 20% 34% 30% 4	600
	21st to end	Night	5% 10% 19% 32% 27% 7%	769
October	1st to 10th	Night	6% 14% 26% 34% 18% 3	800
	11th to 20th	Night	5% 14% 28% 33% 16% 4	800
	21st to end	Night	5% 14% 26% 34% 17% 4	880
November	1st to 10th	Night	5% 16% 28% 32% 17% 2	857
	11th to 20th	Night	6% 14% 34% 33% 11% 2	1050
	21st to end	Night	7% 17% 29% 32% 13% 3	1050
December	1st to 10th	Night	4 15% 38% 33% 9% 1	1050
	11th to 20th	Night	6% 19% 36% 28% 9% 1	1050
	21st to end	Night	9% 15% 40% 29% 6% 1	1155

Page generated at 2026-02-12 23:42:15. Version ac07

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