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 2024-11-30.

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	4 7% 4 9% 6% 5% 5% 4 5% 6% 45%	105313
	Night	1 4 2 7% 4 4 4 4 6% 8% 56%	103033
Transparency	Day	37% 5% 9% 19% 21% 9%	105071
	Night	25% 5% 11% 25% 25% 8%	102864
Seeing	Day	15% 22% 26% 22% 11% 3	15392
	Night	6% 13% 28% 32% 19% 3	25548

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 12% 10% 5% 4 4 7% 8% 45%	2726
	11th to 20th	Day	3 5% 12% 6% 6% 5% 3 6% 8% 45%	2860
	21st to end	Day	8% 4 13% 6% 4 3 3 5% 6% 47%	3146
February	1st to 10th	Day	4 4 14% 5% 4 4 4 6% 7% 46%	1710
	11th to 20th	Day	5% 4 9% 7% 6% 4 4 6% 8% 46%	1731
	21st to end	Day	4 4 13% 7% 6% 4 3 5% 7% 46%	1570
March	1st to 10th	Day	6% 7% 13% 6% 4 4 3 4 6% 48%	3400
	11th to 20th	Day	1 10% 9% 15% 6% 5% 5% 3 5% 5% 36%	3490
	21st to end	Day	17% 8% 14% 6% 5% 4 3 4 6% 33%	3873
April	1st to 10th	Day	1 9% 4 9% 6% 5% 4 4 6% 7% 46%	2280
	11th to 20th	Day	1 11% 5% 11% 6% 5% 5% 4 5% 6% 42%	2251
	21st to end	Day	1 9% 5% 8% 6% 5% 5% 4 6% 7% 44%	2280
May	1st to 10th	Day	2 11% 4 9% 5% 5% 5% 4 5% 7% 42%	3972
	11th to 20th	Day	2 9% 3 7% 6% 4 5% 5% 7% 8% 42%	4180
	21st to end	Day	3 6% 3 6% 4 5% 6% 4 6% 8% 49%	4825
June	1st to 10th	Day	3 5% 2 6% 5% 5% 5% 4 6% 7% 51%	2660
	11th to 20th	Day	4 5% 3 7% 4 4 5% 3 5% 6% 55%	2660
	21st to end	Day	5% 6% 3 6% 6% 5% 4 5% 6% 7% 49%	2660
July	1st to 10th	Day	6% 5% 2 6% 5% 4 4 3 5% 5% 56%	4430
	11th to 20th	Day	6% 5% 3 9% 7% 7% 9% 6% 9% 9% 30%	4150
	21st to end	Day	9% 8% 4 10% 7% 6% 6% 4 5% 6% 35%	4454
August	1st to 10th	Day	12% 8% 4 11% 8% 7% 7% 5% 7% 8% 23%	4092
	11th to 20th	Day	8% 7% 4 10% 7% 7% 7% 5% 6% 6% 33%	3857
	21st to end	Day	9% 8% 3 12% 8% 6% 6% 5% 6% 7% 29%	4180
September	1st to 10th	Day	9% 9% 3 9% 5% 6% 4 4 5% 5% 40%	2280
	11th to 20th	Day	9% 7% 4 8% 6% 4 4 3 4 5% 47%	2280
	21st to end	Day	6% 6% 3 8% 4 4 4 3 4 4 54%	2010
October	1st to 10th	Day	6% 7% 2 5% 3 4 2 3 3 5% 59%	3170
	11th to 20th	Day	4 8% 3 7% 5% 5% 6% 4 5% 5% 47%	3150
	21st to end	Day	2 5% 3 5% 3 3 3 2 3 4 68%	3438
November	1st to 10th	Day	1 4 2 6% 3 3 3 2 5% 5% 67%	1901
	11th to 20th	Day	4 2 5% 4 3 3 3 4 5% 68%	1800
	21st to end	Day	5% 2 9% 4 3 3 3 4 5% 62%	1607
December	1st to 10th	Day	4 4 6% 6% 4 4 3 5% 6% 57%	1520
	11th to 20th	Day	7% 3 8% 5% 4 5% 4 5% 8% 51%	1926
	21st to end	Day	4 3 10% 5% 5% 4 3 6% 8% 54%	2794
January	1st to 10th	Night	2 2 13% 9% 7% 4 4 7% 6% 46%	4257
	11th to 20th	Night	3 4 14% 5% 6% 3 3 5% 8% 48%	4110
	21st to end	Night	4 3 10% 6% 6% 5% 4 6% 7% 49%	4521
February	1st to 10th	Night	2 3 9% 6% 5% 4 4 5% 7% 55%	2470
	11th to 20th	Night	3 2 6% 6% 5% 4 4 7% 8% 55%	2334
	21st to end	Night	3 3 7% 6% 6% 5% 4 5% 8% 53%	1884
March	1st to 10th	Night	3 6% 7% 4 3 4 4 6% 7% 56%	3470
	11th to 20th	Night	5% 5% 13% 5% 5% 5% 5% 6% 7% 42%	3490
	21st to end	Night	9% 4 11% 6% 5% 5% 4 6% 8% 40%	3776
April	1st to 10th	Night	5% 2 6% 6% 4 4 3 7% 7% 55%	1900
	11th to 20th	Night	1 6% 3 9% 4 6% 4 4 5% 8% 49%	1877
	21st to end	Night	1 6% 4 7% 4 4 3 3 6% 8% 54%	1900
May	1st to 10th	Night	1 7% 4 6% 4 4 4 4 5% 7% 55%	2994
	11th to 20th	Night	2 5% 1 4 4 4 3 4 7% 9% 57%	2721
	21st to end	Night	2 3 2 4 2 2 3 3 4 6% 69%	2762
June	1st to 10th	Night	1 2 1 3 2 3 4 3 5% 8% 68%	1520
	11th to 20th	Night	2 3 1 2 2 3 4 2 5% 6% 69%	1520
	21st to end	Night	2 3 1 3 3 4 5% 3 6% 8% 62%	1520
July	1st to 10th	Night	2 3 1 3 3 3 3 4 5% 6% 65%	2540
	11th to 20th	Night	1 2 1 3 4 4 5% 5% 7% 13% 55%	2816
	21st to end	Night	3 3 2 5% 4 5% 5% 5% 8% 10% 49%	3109
August	1st to 10th	Night	3 4 2 5% 5% 5% 6% 8% 9% 13% 39%	2847
	11th to 20th	Night	3 3 1 3 3 3 4 5% 8% 13% 53%	2981
	21st to end	Night	3 5% 2 8% 5% 6% 6% 4 7% 9% 43%	3487
September	1st to 10th	Night	4 4 2 6% 5% 4 4 5% 7% 8% 52%	1900
	11th to 20th	Night	3 3 2 5% 3 4 5% 3 6% 8% 60%	1900
	21st to end	Night	2 4 1 4 3 3 3 3 4 6% 67%	2165
October	1st to 10th	Night	2 3 1 3 1 2 2 2 3 5% 75%	3800
	11th to 20th	Night	1 4 2 5% 3 4 5% 3 5% 7% 61%	3778
	21st to end	Night	1 4 2 4 3 2 3 2 3 5% 71%	4120
November	1st to 10th	Night	4 2 4 3 3 4 4 5% 7% 64%	2375
	11th to 20th	Night	2 1 4 3 3 3 3 5% 7% 69%	2600
	21st to end	Night	1 5% 3 6% 4 4 3 4 5% 6% 60%	2785
December	1st to 10th	Night	2 2 5% 4 3 5% 3 5% 8% 62%	2660
	11th to 20th	Night	4 3 6% 5% 5% 4 5% 7% 10% 51%	3271
	21st to end	Night	3 2 9% 5% 5% 5% 4 6% 7% 54%	4873

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	30% 8% 14% 19% 22% 6%	2727
	11th to 20th	Day	32% 4 16% 25% 20% 3	2860
	21st to end	Day	37% 4 7% 27% 19% 6%	3146
February	1st to 10th	Day	34% 4 15% 22% 16% 9%	1710
	11th to 20th	Day	33% 4 10% 20% 23% 9%	1740
	21st to end	Day	37% 4 6% 20% 22% 11%	1570
March	1st to 10th	Day	38% 3 6% 21% 23% 10%	3400
	11th to 20th	Day	51% 2 7% 26% 12% 3	3490
	21st to end	Day	52% 4 6% 20% 15% 3	3873
April	1st to 10th	Day	35% 6% 10% 22% 20% 7%	2280
	11th to 20th	Day	40% 4 9% 23% 20% 5%	2254
	21st to end	Day	37% 5% 10% 30% 16% 3	2280
May	1st to 10th	Day	39% 5% 7% 19% 22% 7%	3972
	11th to 20th	Day	37% 4 7% 27% 20% 5%	4183
	21st to end	Day	32% 5% 6% 20% 32% 5%	4825
June	1st to 10th	Day	31% 4 9% 25% 22% 9%	2660
	11th to 20th	Day	30% 4 6% 18% 26% 17%	2660
	21st to end	Day	35% 4 5% 16% 23% 16%	2660
July	1st to 10th	Day	31% 4 5% 8% 17% 35%	4361
	11th to 20th	Day	45% 7% 13% 17% 13% 5%	4079
	21st to end	Day	47% 5% 11% 12% 15% 10%	4314
August	1st to 10th	Day	55% 8% 14% 10% 10% 3	4078
	11th to 20th	Day	48% 8% 10% 11% 17% 5%	3896
	21st to end	Day	50% 6% 9% 14% 16% 5%	4179
September	1st to 10th	Day	45% 4 8% 13% 22% 8%	2280
	11th to 20th	Day	40% 4 7% 16% 24% 9%	2280
	21st to end	Day	33% 4 5% 22% 29% 8%	2010
October	1st to 10th	Day	30% 3 4 19% 33% 12%	3170
	11th to 20th	Day	35% 4 7% 21% 26% 7%	3150
	21st to end	Day	21% 2 5% 20% 40% 11%	3438
November	1st to 10th	Day	20% 4 9% 25% 32% 10%	1901
	11th to 20th	Day	17% 3 10% 29% 30% 11%	1800
	21st to end	Day	24% 3 9% 25% 25% 14%	1607
December	1st to 10th	Day	27% 4 16% 26% 20% 7%	1520
	11th to 20th	Day	31% 5% 13% 23% 24% 5%	1924
	21st to end	Day	27% 5% 9% 20% 23% 16%	2794
January	1st to 10th	Night	33% 6% 9% 27% 18% 7%	4257
	11th to 20th	Night	32% 4 15% 26% 19% 4	4110
	21st to end	Night	30% 5% 8% 28% 24% 4	4521
February	1st to 10th	Night	27% 4 15% 24% 21% 9%	2470
	11th to 20th	Night	24% 4 11% 26% 26% 9%	2335
	21st to end	Night	26% 5% 8% 24% 27% 10%	1884
March	1st to 10th	Night	26% 4 8% 23% 36% 3	3470
	11th to 20th	Night	40% 3 10% 29% 15% 3	3490
	21st to end	Night	39% 5% 11% 27% 16% 2	3776
April	1st to 10th	Night	25% 5% 16% 26% 21% 7%	1900
	11th to 20th	Night	30% 6% 11% 27% 23% 4	1877
	21st to end	Night	27% 5% 13% 33% 20% 2	1900
May	1st to 10th	Night	26% 6% 7% 23% 34% 3	2994
	11th to 20th	Night	23% 4 10% 37% 24% 2	2722
	21st to end	Night	17% 3 6% 28% 36% 9%	2762
June	1st to 10th	Night	15% 4 12% 29% 31% 9%	1520
	11th to 20th	Night	16% 3 8% 22% 33% 18%	1520
	21st to end	Night	18% 4 9% 24% 28% 17%	1520
July	1st to 10th	Night	21% 5% 9% 10% 20% 35%	2500
	11th to 20th	Night	18% 7% 19% 32% 17% 7%	2764
	21st to end	Night	27% 8% 22% 19% 12% 12%	3011
August	1st to 10th	Night	33% 13% 24% 13% 13% 5%	2838
	11th to 20th	Night	22% 11% 25% 13% 22% 7%	3008
	21st to end	Night	35% 8% 14% 20% 18% 5%	3487
September	1st to 10th	Night	27% 7% 13% 20% 25% 8%	1900
	11th to 20th	Night	22% 5% 13% 21% 29% 10%	1900
	21st to end	Night	19% 3 6% 32% 33% 7%	2165
October	1st to 10th	Night	15% 2 6% 23% 41% 13%	3800
	11th to 20th	Night	21% 4 9% 34% 25% 6%	3778
	21st to end	Night	17% 3 6% 23% 41% 11%	4120
November	1st to 10th	Night	19% 4 11% 26% 29% 10%	2375
	11th to 20th	Night	14% 3 10% 30% 33% 11%	2600
	21st to end	Night	23% 5% 8% 24% 27% 13%	2785
December	1st to 10th	Night	21% 5% 17% 25% 23% 10%	2660
	11th to 20th	Night	26% 6% 12% 23% 25% 8%	3272
	21st to end	Night	28% 5% 10% 20% 22% 15%	4873

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	15% 22% 31% 22% 9% 1	270
	11th to 20th	Day	16% 31% 23% 24% 6%	270
	21st to end	Day	7% 25% 31% 27% 8% 1	297
February	1st to 10th	Day	17% 35% 32% 14% 1 1	270
	11th to 20th	Day	15% 39% 26% 14% 6%	270
	21st to end	Day	27% 35% 19% 16% 3	225
March	1st to 10th	Day	21% 35% 23% 17% 4	427
	11th to 20th	Day	20% 27% 28% 19% 6% 1	460
	21st to end	Day	25% 34% 27% 12% 2	506
April	1st to 10th	Day	21% 31% 28% 14% 5% 1	460
	11th to 20th	Day	27% 35% 25% 9% 4 1	452
	21st to end	Day	19% 35% 27% 14% 4 1	460
May	1st to 10th	Day	20% 35% 30% 10% 5%	463
	11th to 20th	Day	13% 29% 31% 17% 8% 2	545
	21st to end	Day	16% 26% 25% 19% 11% 3	734
June	1st to 10th	Day	9% 15% 28% 26% 17% 4	680
	11th to 20th	Day	9% 20% 29% 25% 13% 4	680
	21st to end	Day	6% 18% 27% 26% 19% 5%	680
July	1st to 10th	Day	9% 9% 20% 33% 22% 7%	671
	11th to 20th	Day	15% 7% 17% 32% 21% 7%	509
	21st to end	Day	16% 9% 17% 30% 21% 7%	531
August	1st to 10th	Day	18% 10% 21% 28% 17% 6%	487
	11th to 20th	Day	12% 12% 23% 32% 15% 6%	477
	21st to end	Day	15% 9% 25% 29% 16% 4	539
September	1st to 10th	Day	15% 11% 23% 27% 17% 7%	490
	11th to 20th	Day	16% 16% 31% 22% 11% 3	490
	21st to end	Day	14% 20% 25% 22% 13% 7%	383
October	1st to 10th	Day	18% 18% 19% 22% 18% 5%	300
	11th to 20th	Day	15% 23% 25% 22% 13% 3	300
	21st to end	Day	16% 23% 26% 23% 11% 1	330
November	1st to 10th	Day	16% 27% 25% 21% 9% 2	300
	11th to 20th	Day	13% 27% 27% 21% 10% 1	300
	21st to end	Day	11% 26% 29% 19% 12% 2	299
December	1st to 10th	Day	16% 24% 31% 19% 9% 2	270
	11th to 20th	Day	16% 26% 27% 21% 9% 1	270
	21st to end	Day	18% 29% 26% 20% 5% 2	297
January	1st to 10th	Night	6% 14% 32% 32% 14% 2	855
	11th to 20th	Night	6% 15% 34% 30% 13% 2	760
	21st to end	Night	2 15% 33% 36% 10% 4	836
February	1st to 10th	Night	5% 16% 39% 31% 8% 1	760
	11th to 20th	Night	5% 17% 41% 29% 8%	744
	21st to end	Night	9% 16% 43% 28% 5%	628
March	1st to 10th	Night	7% 20% 34% 29% 9% 2	760
	11th to 20th	Night	5% 14% 34% 32% 14% 1	760
	21st to end	Night	7% 18% 38% 29% 7% 1	809
April	1st to 10th	Night	5% 24% 35% 28% 6%	570
	11th to 20th	Night	9% 21% 33% 27% 10%	563
	21st to end	Night	5% 19% 35% 28% 11% 2	570
May	1st to 10th	Night	7% 14% 34% 34% 11% 1	570
	11th to 20th	Night	7% 10% 26% 35% 19% 3	561
	21st to end	Night	8% 16% 27% 27% 20% 2	617
June	1st to 10th	Night	2 9% 22% 38% 26% 1	570
	11th to 20th	Night	6% 12% 22% 38% 20% 3	570
	21st to end	Night	2 5% 19% 41% 30% 3	570
July	1st to 10th	Night	5% 3 12% 37% 41% 3	555
	11th to 20th	Night	3 3 7% 30% 48% 9%	552
	21st to end	Night	6% 2 5% 30% 48% 8%	624
August	1st to 10th	Night	5% 4 7% 31% 47% 6%	567
	11th to 20th	Night	8% 2 8% 36% 41% 5%	564
	21st to end	Night	6% 5% 8% 34% 41% 6%	627
September	1st to 10th	Night	5% 4 12% 38% 38% 4	570
	11th to 20th	Night	5% 7% 18% 35% 31% 4	570
	21st to end	Night	5% 10% 18% 31% 28% 7%	730
October	1st to 10th	Night	5% 14% 24% 35% 19% 3	760
	11th to 20th	Night	4 14% 28% 34% 16% 4	760
	21st to end	Night	6% 14% 25% 34% 18% 4	836
November	1st to 10th	Night	5% 16% 27% 33% 18% 2	815
	11th to 20th	Night	6% 14% 34% 33% 11% 3	1000
	21st to end	Night	7% 17% 28% 32% 14% 3	1000
December	1st to 10th	Night	5% 16% 37% 32% 9% 1	950
	11th to 20th	Night	6% 19% 34% 29% 10% 2	950
	21st to end	Night	8% 14% 40% 30% 7% 1	1045

Page generated at 2024-11-27 15:30:54. Version ac07

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