Red Feather Lakes
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Red Feather Lakes clear sky chart from 2005-11-06 to 2026-08-30.

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	3 5% 2 6% 4 4 5% 4 7% 8% 51%	153064
	Night	2 5% 2 5% 3 3 3 3 5% 8% 60%	146705
Transparency	Day	27% 6% 11% 24% 22% 9%	147981
	Night	22% 5% 12% 28% 25% 8%	142798
Seeing	Day	18% 24% 31% 18% 7% 2	18188
	Night	17% 26% 27% 21% 8% 1	28130

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	1 3 2 8% 4 3 4 3 5% 9% 59%	4720
	11th to 20th	Day	2 1 4 4 4 4 4 5% 11% 61%	4842
	21st to end	Day	3 2 6% 3 3 4 3 5% 7% 62%	5844
February	1st to 10th	Day	4 3 7% 4 3 4 4 7% 8% 55%	1890
	11th to 20th	Day	4 3 6% 5% 3 5% 4 7% 11% 53%	1963
	21st to end	Day	5% 3 6% 3 4 4 3 6% 8% 58%	1730
March	1st to 10th	Day	1 7% 4 8% 4 3 4 3 6% 7% 53%	4600
	11th to 20th	Day	1 9% 3 7% 4 5% 5% 5% 8% 8% 45%	5110
	21st to end	Day	2 7% 2 5% 4 4 5% 5% 8% 11% 50%	5907
April	1st to 10th	Day	3 7% 3 6% 4 4 4 4 7% 8% 51%	2520
	11th to 20th	Day	6% 10% 4 8% 4 4 5% 3 8% 8% 42%	2491
	21st to end	Day	5% 11% 3 8% 6% 5% 5% 5% 7% 8% 37%	2520
May	1st to 10th	Day	8% 11% 3 6% 4 4 4 4 6% 7% 43%	7675
	11th to 20th	Day	6% 8% 3 6% 4 5% 5% 4 7% 8% 44%	8191
	21st to end	Day	5% 6% 2 6% 5% 5% 7% 6% 8% 10% 41%	9026
June	1st to 10th	Day	4 4 2 4 4 5% 6% 7% 8% 9% 45%	2940
	11th to 20th	Day	5% 4 2 5% 3 5% 5% 4 6% 9% 53%	2940
	21st to end	Day	2 4 2 5% 5% 5% 5% 5% 7% 9% 52%	2940
July	1st to 10th	Day	3 3 1 5% 4 5% 7% 6% 8% 9% 49%	8249
	11th to 20th	Day	1 2 1 5% 4 5% 6% 5% 8% 9% 53%	8250
	21st to end	Day	4 4 2 7% 5% 6% 7% 6% 8% 9% 41%	8839
August	1st to 10th	Day	3 5% 2 6% 4 6% 6% 6% 8% 10% 44%	5909
	11th to 20th	Day	3 3 2 6% 4 5% 6% 4 7% 9% 51%	5620
	21st to end	Day	6% 6% 2 8% 5% 5% 6% 5% 6% 8% 43%	6093
September	1st to 10th	Day	5% 5% 2 4 4 4 4 4 5% 7% 57%	2400
	11th to 20th	Day	6% 3 2 5% 3 4 4 4 6% 7% 55%	2400
	21st to end	Day	6% 6% 2 4 2 3 2 2 4 6% 62%	2174
October	1st to 10th	Day	3 4 1 3 2 2 3 2 3 5% 71%	3270
	11th to 20th	Day	4 4 1 5% 4 4 4 3 6% 8% 58%	3250
	21st to end	Day	3 7% 2 4 3 3 4 3 5% 6% 62%	3430
November	1st to 10th	Day	2 4 2 3 3 2 4 3 6% 7% 64%	1853
	11th to 20th	Day	1 4 2 3 2 3 3 3 5% 9% 63%	1890
	21st to end	Day	4 2 5% 5% 4 4 3 6% 8% 58%	1690
December	1st to 10th	Day	3 1 3 2 2 2 3 4 7% 72%	2700
	11th to 20th	Day	1 4 2 4 3 2 3 3 6% 9% 64%	3106
	21st to end	Day	1 5% 3 7% 4 4 4 3 6% 9% 54%	4092
January	1st to 10th	Night	3 2 6% 3 3 4 4 6% 9% 60%	8201
	11th to 20th	Night	2 1 4 4 4 3 3 5% 9% 66%	8190
	21st to end	Night	3 2 6% 4 4 3 3 4 7% 64%	8370
February	1st to 10th	Night	4 2 6% 3 3 4 3 6% 9% 60%	2730
	11th to 20th	Night	4 2 6% 4 3 3 3 6% 8% 60%	2543
	21st to end	Night	6% 3 5% 2 3 3 3 4 7% 63%	2076
March	1st to 10th	Night	6% 4 8% 4 3 3 3 5% 6% 56%	5478
	11th to 20th	Night	1 8% 3 6% 3 3 3 3 5% 7% 58%	5110
	21st to end	Night	2 7% 2 6% 3 3 3 3 6% 9% 55%	5295
April	1st to 10th	Night	2 6% 2 5% 5% 4 4 3 6% 7% 57%	2100
	11th to 20th	Night	5% 7% 2 6% 3 3 3 4 4 8% 53%	2077
	21st to end	Night	8% 9% 2 5% 4 3 3 3 6% 8% 49%	2100
May	1st to 10th	Night	9% 10% 2 5% 3 4 4 3 4 6% 50%	5252
	11th to 20th	Night	6% 7% 2 5% 4 4 4 4 6% 7% 51%	4701
	21st to end	Night	5% 8% 2 5% 3 4 4 3 6% 8% 52%	5181
June	1st to 10th	Night	4 4 1 3 2 3 4 4 7% 9% 59%	1680
	11th to 20th	Night	4 3 1 3 2 3 5% 4 5% 8% 62%	1680
	21st to end	Night	4 3 1 3 2 3 3 4 6% 7% 62%	1680
July	1st to 10th	Night	2 3 1 4 3 4 4 4 6% 9% 60%	4740
	11th to 20th	Night	2 3 1 3 3 3 4 4 6% 9% 63%	4740
	21st to end	Night	2 4 2 5% 4 5% 6% 6% 8% 9% 51%	5266
August	1st to 10th	Night	4 5% 1 4 3 3 5% 4 7% 10% 54%	4123
	11th to 20th	Night	2 3 2 4 3 4 5% 4 7% 9% 58%	4449
	21st to end	Night	5% 5% 2 4 4 4 5% 4 7% 9% 51%	5083
September	1st to 10th	Night	5% 4 1 4 3 3 4 3 4 7% 62%	2000
	11th to 20th	Night	6% 3 1 4 3 3 3 2 5% 7% 63%	2000
	21st to end	Night	6% 4 1 3 3 3 3 2 4 7% 64%	2224
October	1st to 10th	Night	3 4 1 3 2 2 2 2 4 5% 74%	3920
	11th to 20th	Night	3 5% 2 4 3 3 3 3 6% 8% 60%	3898
	21st to end	Night	2 5% 2 4 3 3 2 2 4 7% 65%	4338
November	1st to 10th	Night	2 3 1 3 3 3 3 3 5% 6% 68%	2665
	11th to 20th	Night	1 4 1 3 3 2 2 3 5% 8% 66%	2730
	21st to end	Night	1 4 2 5% 3 3 3 4 5% 7% 62%	2926
December	1st to 10th	Night	2 1 3 1 2 2 2 4 7% 75%	4710
	11th to 20th	Night	1 4 2 4 2 2 2 3 5% 8% 68%	5321
	21st to end	Night	1 5% 2 6% 4 3 4 3 6% 9% 57%	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	23% 3 13% 30% 26% 4	4723
	11th to 20th	Day	16% 5% 16% 27% 26% 9%	4842
	21st to end	Day	20% 5% 11% 28% 26% 10%	5844
February	1st to 10th	Day	25% 6% 17% 26% 19% 5%	1890
	11th to 20th	Day	24% 5% 15% 29% 21% 5%	1972
	21st to end	Day	23% 5% 13% 25% 26% 7%	1730
March	1st to 10th	Day	29% 4 7% 23% 29% 8%	4600
	11th to 20th	Day	31% 7% 11% 26% 21% 4	5110
	21st to end	Day	25% 7% 15% 37% 14% 2	5907
April	1st to 10th	Day	28% 6% 14% 26% 19% 7%	2520
	11th to 20th	Day	37% 4 13% 23% 17% 5%	2494
	21st to end	Day	40% 7% 10% 27% 15% 2	2520
May	1st to 10th	Day	37% 6% 9% 26% 18% 4	7675
	11th to 20th	Day	33% 8% 9% 20% 22% 7%	8195
	21st to end	Day	31% 8% 12% 23% 21% 5%	9027
June	1st to 10th	Day	29% 10% 18% 21% 17% 6%	2940
	11th to 20th	Day	27% 7% 10% 19% 24% 14%	2940
	21st to end	Day	25% 7% 11% 21% 23% 13%	2940
July	1st to 10th	Day	24% 6% 10% 13% 24% 23%	8181
	11th to 20th	Day	21% 7% 10% 24% 19% 19%	8175
	21st to end	Day	32% 9% 13% 17% 15% 13%	8643
August	1st to 10th	Day	33% 10% 14% 17% 16% 10%	4338
	11th to 20th	Day	28% 8% 12% 16% 21% 15%	4102
	21st to end	Day	28% 6% 11% 18% 24% 13%	4420
September	1st to 10th	Day	25% 6% 9% 19% 27% 14%	2400
	11th to 20th	Day	26% 6% 9% 22% 26% 11%	2400
	21st to end	Day	25% 4 8% 21% 34% 9%	2174
October	1st to 10th	Day	18% 3 5% 16% 35% 22%	3270
	11th to 20th	Day	23% 5% 9% 33% 25% 6%	3250
	21st to end	Day	23% 4 7% 29% 31% 6%	3430
November	1st to 10th	Day	19% 4 13% 28% 30% 6%	1853
	11th to 20th	Day	19% 5% 13% 31% 26% 7%	1890
	21st to end	Day	23% 4 12% 31% 21% 9%	1690
December	1st to 10th	Day	13% 4 13% 35% 29% 6%	2700
	11th to 20th	Day	17% 5% 12% 37% 26% 2	3104
	21st to end	Day	26% 6% 10% 29% 21% 9%	4092
January	1st to 10th	Night	21% 4 10% 36% 23% 6%	8202
	11th to 20th	Night	16% 3 16% 27% 28% 10%	8190
	21st to end	Night	21% 4 11% 25% 27% 11%	8370
February	1st to 10th	Night	21% 5% 19% 28% 22% 6%	2730
	11th to 20th	Night	22% 5% 15% 32% 22% 4	2544
	21st to end	Night	22% 3 12% 27% 27% 10%	2076
March	1st to 10th	Night	28% 4 7% 21% 30% 10%	5478
	11th to 20th	Night	25% 4 11% 22% 30% 8%	5110
	21st to end	Night	25% 6% 16% 35% 17% 1	5295
April	1st to 10th	Night	25% 6% 13% 29% 20% 7%	2100
	11th to 20th	Night	29% 5% 13% 28% 19% 5%	2077
	21st to end	Night	32% 6% 10% 30% 20% 1	2100
May	1st to 10th	Night	34% 5% 10% 29% 18% 3	5250
	11th to 20th	Night	30% 7% 12% 27% 18% 5%	4702
	21st to end	Night	29% 5% 13% 28% 22% 2	5182
June	1st to 10th	Night	20% 8% 20% 28% 18% 6%	1680
	11th to 20th	Night	18% 6% 11% 25% 24% 16%	1680
	21st to end	Night	18% 6% 10% 24% 26% 16%	1680
July	1st to 10th	Night	19% 4 9% 20% 31% 17%	4700
	11th to 20th	Night	16% 4 14% 28% 22% 15%	4692
	21st to end	Night	26% 8% 18% 20% 16% 12%	5151
August	1st to 10th	Night	25% 7% 17% 23% 20% 8%	3018
	11th to 20th	Night	23% 7% 19% 21% 20% 10%	3243
	21st to end	Night	21% 6% 14% 24% 28% 8%	3687
September	1st to 10th	Night	22% 5% 10% 22% 27% 15%	2000
	11th to 20th	Night	21% 4 9% 27% 26% 13%	2000
	21st to end	Night	21% 4 8% 27% 30% 10%	2224
October	1st to 10th	Night	15% 3 6% 23% 34% 19%	3920
	11th to 20th	Night	22% 5% 9% 33% 25% 7%	3898
	21st to end	Night	20% 3 8% 30% 30% 8%	4338
November	1st to 10th	Night	17% 5% 14% 28% 29% 8%	2665
	11th to 20th	Night	17% 4 15% 31% 26% 7%	2730
	21st to end	Night	21% 5% 11% 31% 25% 7%	2926
December	1st to 10th	Night	11% 4 13% 37% 30% 6%	4710
	11th to 20th	Night	16% 5% 10% 37% 28% 4	5322
	21st to end	Night	22% 7% 12% 26% 26% 7%	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	30% 32% 23% 8% 5% 2	330
	11th to 20th	Day	33% 38% 18% 10% 1	330
	21st to end	Day	29% 40% 22% 6% 3	363
February	1st to 10th	Day	42% 34% 18% 4 1 1	330
	11th to 20th	Day	37% 33% 24% 5% 2	330
	21st to end	Day	38% 38% 19% 4	273
March	1st to 10th	Day	28% 34% 28% 9% 1	330
	11th to 20th	Day	29% 31% 28% 10% 3	540
	21st to end	Day	24% 36% 31% 7% 2	594
April	1st to 10th	Day	27% 33% 29% 9% 1	540
	11th to 20th	Day	29% 36% 28% 5% 1	532
	21st to end	Day	24% 32% 29% 11% 3 1	540
May	1st to 10th	Day	22% 30% 28% 14% 5% 1	676
	11th to 20th	Day	20% 18% 36% 16% 8% 2	775
	21st to end	Day	14% 20% 31% 25% 8% 1	844
June	1st to 10th	Day	9% 18% 33% 26% 12% 3	780
	11th to 20th	Day	11% 21% 40% 19% 7% 2	780
	21st to end	Day	8% 19% 37% 23% 12% 2	780
July	1st to 10th	Day	7% 8% 33% 33% 16% 3	771
	11th to 20th	Day	3 8% 36% 32% 15% 5%	768
	21st to end	Day	6% 8% 33% 32% 17% 4	807
August	1st to 10th	Day	8% 14% 41% 29% 6% 2	567
	11th to 20th	Day	7% 11% 39% 30% 11% 2	557
	21st to end	Day	7% 14% 38% 32% 8% 2	620
September	1st to 10th	Day	8% 16% 38% 27% 10% 2	530
	11th to 20th	Day	10% 20% 40% 22% 8% 1	530
	21st to end	Day	14% 20% 32% 21% 10% 4	335
October	1st to 10th	Day	12% 22% 32% 22% 10% 3	330
	11th to 20th	Day	25% 31% 26% 12% 4 2	330
	21st to end	Day	19% 36% 29% 12% 3	363
November	1st to 10th	Day	27% 32% 25% 9% 6% 1	330
	11th to 20th	Day	27% 38% 24% 9% 2	330
	21st to end	Day	23% 39% 28% 8% 2	330
December	1st to 10th	Day	37% 32% 24% 6% 2	330
	11th to 20th	Day	35% 41% 19% 4 1	330
	21st to end	Day	38% 32% 20% 8% 1 1	363
January	1st to 10th	Night	26% 37% 19% 13% 3 1	1050
	11th to 20th	Night	30% 41% 17% 8% 3	1029
	21st to end	Night	22% 43% 23% 9% 3	924
February	1st to 10th	Night	28% 40% 21% 9% 2	840
	11th to 20th	Night	22% 36% 28% 13% 1	824
	21st to end	Night	29% 39% 23% 8% 1	692
March	1st to 10th	Night	18% 36% 30% 12% 3	840
	11th to 20th	Night	20% 31% 26% 18% 4	840
	21st to end	Night	15% 34% 32% 15% 3 1	790
April	1st to 10th	Night	15% 31% 35% 17% 1	630
	11th to 20th	Night	17% 30% 34% 14% 6%	623
	21st to end	Night	17% 24% 31% 22% 5%	630
May	1st to 10th	Night	16% 18% 36% 22% 7% 1	630
	11th to 20th	Night	19% 11% 29% 29% 12% 1	621
	21st to end	Night	12% 12% 32% 28% 15% 1	683
June	1st to 10th	Night	7% 9% 32% 35% 15% 2	630
	11th to 20th	Night	7% 13% 38% 31% 10%	630
	21st to end	Night	6% 8% 31% 36% 18% 1	630
July	1st to 10th	Night	5% 4 22% 42% 24% 2	615
	11th to 20th	Night	3 3 26% 41% 24% 3	612
	21st to end	Night	5% 3 17% 47% 26% 3	690
August	1st to 10th	Night	6% 4 23% 47% 19% 2	627
	11th to 20th	Night	4 5% 25% 44% 20% 2	624
	21st to end	Night	5% 5% 22% 43% 21% 4	687
September	1st to 10th	Night	8% 6% 23% 42% 18% 4	600
	11th to 20th	Night	9% 9% 29% 36% 15% 2	600
	21st to end	Night	8% 16% 29% 33% 13% 2	629
October	1st to 10th	Night	12% 19% 32% 26% 10% 2	800
	11th to 20th	Night	19% 28% 26% 20% 6% 1	800
	21st to end	Night	15% 33% 34% 12% 4 1	930
November	1st to 10th	Night	16% 35% 31% 13% 4 1	1025
	11th to 20th	Night	25% 36% 27% 10% 1	1050
	21st to end	Night	18% 38% 30% 11% 3	1050
December	1st to 10th	Night	29% 37% 23% 10% 2	1050
	11th to 20th	Night	24% 44% 19% 10% 3	1050
	21st to end	Night	28% 39% 21% 9% 3	1155

Page generated at 2026-08-27 02:07:13. Version ac07

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