Platte River Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Platte River Campground 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	13% 12% 5% 11% 6% 4 4 3 4 6% 32%	130523
	Night	14% 15% 6% 13% 7% 5% 4 3 4 5% 26%	130537
Transparency	Day	52% 5% 11% 20% 10% 1	134010
	Night	60% 5% 10% 16% 8% 1	135112
Seeing	Day	19% 17% 32% 22% 8% 2	17581
	Night	22% 15% 29% 24% 9% 1	27666

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	12% 24% 13% 31% 7% 4 2 1 2 1 3	4691
	11th to 20th	Day	10% 19% 10% 29% 12% 10% 3 1 1 1 2	4710
	21st to end	Day	10% 16% 10% 18% 13% 9% 8% 2 2 2 10%	5156
February	1st to 10th	Day	10% 20% 6% 18% 17% 6% 3 2 3 3 13%	1800
	11th to 20th	Day	12% 16% 7% 18% 12% 8% 4 3 4 3 14%	1998
	21st to end	Day	13% 17% 6% 15% 10% 5% 4 3 4 5% 17%	1650
March	1st to 10th	Day	12% 12% 4 12% 7% 4 4 3 5% 5% 32%	4480
	11th to 20th	Day	11% 11% 6% 13% 5% 4 4 4 6% 8% 29%	4786
	21st to end	Day	22% 11% 7% 14% 5% 4 3 3 3 4 23%	5773
April	1st to 10th	Day	17% 15% 4 9% 5% 4 4 3 5% 6% 29%	2400
	11th to 20th	Day	19% 12% 3 6% 4 4 4 3 4 6% 35%	2442
	21st to end	Day	14% 10% 4 8% 5% 4 5% 4 5% 7% 34%	2600
May	1st to 10th	Day	13% 8% 3 6% 4 4 4 3 5% 7% 44%	5862
	11th to 20th	Day	11% 9% 2 7% 5% 4 4 3 5% 6% 44%	6171
	21st to end	Day	14% 6% 2 7% 5% 4 4 4 5% 6% 44%	6935
June	1st to 10th	Day	12% 5% 2 6% 5% 4 4 3 6% 8% 45%	2800
	11th to 20th	Day	12% 5% 2 6% 4 4 5% 4 6% 8% 44%	2800
	21st to end	Day	13% 6% 2 6% 4 4 4 4 6% 9% 43%	2800
July	1st to 10th	Day	15% 6% 2 5% 3 4 3 4 6% 9% 44%	6360
	11th to 20th	Day	10% 4 2 4 3 3 4 3 5% 8% 53%	6360
	21st to end	Day	9% 5% 2 5% 4 4 4 4 6% 10% 48%	6924
August	1st to 10th	Day	8% 6% 2 6% 5% 4 5% 4 7% 9% 43%	4438
	11th to 20th	Day	14% 5% 2 5% 3 3 3 3 5% 6% 51%	4174
	21st to end	Day	12% 7% 3 6% 4 4 4 4 4 6% 47%	4392
September	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 6% 8% 43%	2400
	11th to 20th	Day	12% 5% 2 4 4 4 4 4 6% 8% 47%	2200
	21st to end	Day	15% 8% 2 7% 4 4 4 4 6% 7% 39%	2200
October	1st to 10th	Day	16% 9% 3 7% 4 4 3 3 6% 7% 37%	2200
	11th to 20th	Day	22% 16% 4 10% 5% 4 4 3 5% 5% 22%	1885
	21st to end	Day	24% 15% 5% 9% 6% 4 4 3 5% 4 21%	1980
November	1st to 10th	Day	19% 17% 4 7% 5% 4 5% 3 4 6% 27%	1852
	11th to 20th	Day	14% 25% 6% 12% 5% 4 4 3 4 5% 16%	1890
	21st to end	Day	20% 24% 9% 14% 4 4 3 2 2 4 14%	1803
December	1st to 10th	Day	13% 33% 14% 17% 6% 3 3 1 2 1 6%	2531
	11th to 20th	Day	12% 27% 12% 21% 9% 4 3 2 2 2 5%	3010
	21st to end	Day	20% 22% 11% 16% 7% 5% 4 2 3 3 8%	4070
January	1st to 10th	Night	13% 24% 9% 29% 7% 3 2 1 2 2 7%	8232
	11th to 20th	Night	9% 22% 10% 25% 15% 9% 2 1 1 1 4	8280
	21st to end	Night	9% 17% 10% 20% 14% 9% 6% 2 2 2 9%	9058
February	1st to 10th	Night	10% 19% 7% 19% 13% 7% 4 3 3 3 12%	2817
	11th to 20th	Night	11% 16% 6% 19% 12% 6% 5% 3 4 4 16%	2399
	21st to end	Night	14% 17% 5% 16% 8% 4 3 3 5% 5% 19%	1980
March	1st to 10th	Night	16% 11% 4 12% 4 4 3 3 5% 6% 33%	5373
	11th to 20th	Night	11% 12% 5% 10% 5% 4 4 4 5% 8% 33%	5174
	21st to end	Night	20% 12% 5% 13% 4 4 3 4 4 5% 27%	5201
April	1st to 10th	Night	18% 13% 4 8% 5% 4 4 3 5% 6% 30%	2000
	11th to 20th	Night	20% 13% 3 7% 4 4 3 3 5% 5% 34%	1907
	21st to end	Night	16% 11% 4 7% 5% 5% 4 3 5% 7% 36%	1800
May	1st to 10th	Night	14% 8% 2 6% 4 4 4 3 6% 8% 41%	4033
	11th to 20th	Night	12% 9% 2 7% 5% 4 5% 4 5% 6% 40%	3735
	21st to end	Night	18% 7% 3 6% 4 3 4 3 5% 6% 42%	3942
June	1st to 10th	Night	14% 7% 2 6% 5% 4 5% 3 5% 7% 43%	1600
	11th to 20th	Night	12% 6% 3 7% 6% 4 3 4 6% 8% 40%	1600
	21st to end	Night	12% 6% 3 6% 5% 4 4 4 7% 7% 44%	1600
July	1st to 10th	Night	13% 7% 2 6% 4 4 5% 3 6% 8% 42%	3618
	11th to 20th	Night	8% 6% 2 6% 4 4 4 3 4 7% 53%	3617
	21st to end	Night	7% 5% 2 6% 4 4 5% 4 5% 7% 49%	3947
August	1st to 10th	Night	11% 6% 3 8% 5% 4 5% 4 5% 8% 42%	2715
	11th to 20th	Night	13% 6% 2 5% 4 3 3 4 4 7% 50%	2875
	21st to end	Night	10% 6% 2 7% 5% 4 4 3 4 7% 48%	3503
September	1st to 10th	Night	12% 6% 2 6% 4 3 3 3 6% 7% 48%	2000
	11th to 20th	Night	13% 6% 2 6% 4 4 4 3 6% 6% 49%	2179
	21st to end	Night	16% 8% 2 7% 4 4 4 4 5% 6% 39%	2200
October	1st to 10th	Night	18% 8% 3 7% 4 3 3 3 4 6% 39%	2200
	11th to 20th	Night	23% 14% 4 10% 5% 4 3 3 4 5% 25%	2511
	21st to end	Night	25% 15% 4 9% 5% 4 3 3 4 5% 23%	2860
November	1st to 10th	Night	17% 17% 5% 8% 5% 5% 4 3 4 6% 27%	2666
	11th to 20th	Night	16% 24% 6% 13% 5% 4 4 2 3 3 19%	2730
	21st to end	Night	17% 24% 9% 13% 4 4 3 3 4 4 14%	2814
December	1st to 10th	Night	12% 28% 15% 18% 6% 3 3 2 2 2 8%	4843
	11th to 20th	Night	13% 26% 10% 21% 10% 3 2 2 3 3 8%	5378
	21st to end	Night	22% 22% 10% 14% 6% 4 3 2 3 3 12%	7150

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	92% 2 4 2	4692
	11th to 20th	Day	94% 3 2 2	4710
	21st to end	Day	83% 3 7% 6% 1	5156
February	1st to 10th	Day	78% 4 8% 9% 1	1800
	11th to 20th	Day	74% 6% 9% 8% 3	2008
	21st to end	Day	68% 6% 9% 12% 4 1	1650
March	1st to 10th	Day	53% 6% 15% 16% 10% 1	4480
	11th to 20th	Day	52% 6% 14% 18% 8% 1	4786
	21st to end	Day	65% 6% 9% 14% 7%	5775
April	1st to 10th	Day	55% 6% 10% 20% 10%	2400
	11th to 20th	Day	50% 6% 9% 20% 14% 2	2442
	21st to end	Day	48% 6% 11% 18% 15% 2	2600
May	1st to 10th	Day	39% 6% 10% 24% 18% 2	5897
	11th to 20th	Day	41% 5% 10% 25% 18% 2	6175
	21st to end	Day	40% 6% 10% 23% 19% 2	6949
June	1st to 10th	Day	36% 7% 13% 27% 15% 2	2800
	11th to 20th	Day	37% 6% 14% 24% 17% 1	2800
	21st to end	Day	37% 6% 17% 25% 14% 1	2800
July	1st to 10th	Day	36% 5% 15% 30% 12% 1	6291
	11th to 20th	Day	28% 5% 15% 37% 14% 1	6285
	21st to end	Day	30% 6% 15% 30% 17% 1	6728
August	1st to 10th	Day	36% 6% 15% 30% 13% 1	4423
	11th to 20th	Day	34% 5% 14% 32% 14% 1	4213
	21st to end	Day	38% 6% 14% 30% 12% 1	4391
September	1st to 10th	Day	39% 6% 15% 26% 13% 1	2400
	11th to 20th	Day	35% 7% 17% 30% 11% 1	2200
	21st to end	Day	43% 6% 15% 26% 10%	2200
October	1st to 10th	Day	32% 4 9% 35% 19% 1	3590
	11th to 20th	Day	55% 5% 11% 19% 9%	3036
	21st to end	Day	60% 6% 14% 16% 4	3180
November	1st to 10th	Day	58% 6% 10% 17% 8%	1852
	11th to 20th	Day	70% 6% 10% 10% 4	1890
	21st to end	Day	76% 5% 10% 7% 2	1803
December	1st to 10th	Day	88% 4 3 5% 1	2531
	11th to 20th	Day	87% 4 5% 2 1	3007
	21st to end	Day	82% 5% 5% 6% 2	4070
January	1st to 10th	Night	86% 4 6% 4	8233
	11th to 20th	Night	91% 2 4 2	8280
	21st to end	Night	83% 4 7% 6% 1	9058
February	1st to 10th	Night	78% 4 7% 9% 2	2817
	11th to 20th	Night	72% 5% 8% 12% 3	2400
	21st to end	Night	66% 4 14% 12% 3	1980
March	1st to 10th	Night	52% 4 18% 19% 7%	5373
	11th to 20th	Night	48% 6% 18% 19% 8% 1	5174
	21st to end	Night	58% 6% 11% 17% 7% 1	5201
April	1st to 10th	Night	55% 5% 9% 20% 10% 1	2000
	11th to 20th	Night	52% 5% 7% 21% 12% 3	1907
	21st to end	Night	48% 5% 11% 20% 14% 3	1800
May	1st to 10th	Night	40% 6% 12% 20% 19% 3	4060
	11th to 20th	Night	42% 6% 9% 25% 17% 1	3736
	21st to end	Night	43% 5% 11% 23% 14% 5%	3950
June	1st to 10th	Night	40% 5% 12% 28% 14% 2	1600
	11th to 20th	Night	40% 6% 12% 23% 17% 2	1600
	21st to end	Night	39% 7% 12% 25% 15% 2	1600
July	1st to 10th	Night	39% 5% 13% 26% 14% 3	3580
	11th to 20th	Night	30% 5% 13% 31% 19% 2	3572
	21st to end	Night	32% 6% 15% 27% 18% 2	3832
August	1st to 10th	Night	39% 7% 14% 25% 13% 1	2706
	11th to 20th	Night	34% 5% 15% 30% 15% 1	2902
	21st to end	Night	37% 6% 14% 23% 20% 1	3503
September	1st to 10th	Night	35% 5% 15% 24% 20% 1	2000
	11th to 20th	Night	36% 5% 15% 31% 13% 1	2179
	21st to end	Night	44% 5% 14% 25% 11% 1	2200
October	1st to 10th	Night	40% 4 8% 34% 12% 1	3590
	11th to 20th	Night	54% 4 9% 22% 11%	4086
	21st to end	Night	54% 4 14% 21% 6%	4610
November	1st to 10th	Night	59% 6% 10% 18% 7% 1	2666
	11th to 20th	Night	71% 4 10% 9% 5% 1	2730
	21st to end	Night	75% 5% 10% 8% 1	2814
December	1st to 10th	Night	84% 4 6% 6% 1	4843
	11th to 20th	Night	83% 4 7% 5% 1	5380
	21st to end	Night	78% 5% 10% 5% 3	7150

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	21% 27% 34% 13% 4 1	330
	11th to 20th	Day	27% 24% 37% 10% 2	330
	21st to end	Day	24% 23% 38% 15% 1	363
February	1st to 10th	Day	23% 31% 30% 13% 3 1	330
	11th to 20th	Day	22% 32% 32% 12% 1	315
	21st to end	Day	26% 34% 33% 7%	249
March	1st to 10th	Day	24% 30% 36% 9% 1	300
	11th to 20th	Day	24% 22% 34% 14% 6%	410
	21st to end	Day	29% 20% 28% 17% 5% 1	550
April	1st to 10th	Day	27% 21% 33% 14% 4 1	500
	11th to 20th	Day	28% 19% 31% 14% 7% 1	492
	21st to end	Day	20% 21% 32% 20% 6% 2	500
May	1st to 10th	Day	20% 19% 37% 17% 6% 1	503
	11th to 20th	Day	16% 13% 38% 25% 7% 2	655
	21st to end	Day	15% 12% 35% 27% 10% 2	789
June	1st to 10th	Day	14% 13% 37% 25% 9% 2	730
	11th to 20th	Day	15% 12% 37% 27% 7% 2	730
	21st to end	Day	18% 10% 33% 29% 9% 2	730
July	1st to 10th	Day	10% 8% 31% 35% 12% 4	721
	11th to 20th	Day	10% 10% 31% 32% 14% 3	718
	21st to end	Day	8% 6% 36% 35% 12% 3	794
August	1st to 10th	Day	9% 7% 27% 34% 18% 5%	653
	11th to 20th	Day	14% 8% 23% 33% 15% 8%	519
	21st to end	Day	16% 9% 28% 28% 16% 3	583
September	1st to 10th	Day	20% 10% 27% 26% 12% 5%	530
	11th to 20th	Day	10% 8% 26% 33% 19% 5%	530
	21st to end	Day	17% 13% 23% 30% 14% 3	530
October	1st to 10th	Day	19% 17% 29% 22% 12% 1	530
	11th to 20th	Day	31% 18% 33% 16% 2	368
	21st to end	Day	34% 21% 30% 11% 4	363
November	1st to 10th	Day	32% 20% 28% 17% 2	330
	11th to 20th	Day	28% 26% 34% 9% 2	330
	21st to end	Day	30% 28% 30% 10% 2	330
December	1st to 10th	Day	32% 29% 25% 11% 3	280
	11th to 20th	Day	28% 31% 31% 6% 3	303
	21st to end	Day	33% 29% 28% 9% 1 1	363
January	1st to 10th	Night	24% 23% 33% 16% 4	1050
	11th to 20th	Night	26% 24% 31% 15% 4	1050
	21st to end	Night	23% 18% 34% 20% 5% 1	1155
February	1st to 10th	Night	21% 22% 32% 19% 5% 1	971
	11th to 20th	Night	21% 23% 30% 22% 4	804
	21st to end	Night	25% 23% 31% 18% 3	660
March	1st to 10th	Night	20% 17% 34% 23% 5% 1	800
	11th to 20th	Night	19% 19% 35% 22% 5% 1	800
	21st to end	Night	23% 14% 32% 24% 6% 1	769
April	1st to 10th	Night	24% 16% 32% 23% 5% 1	600
	11th to 20th	Night	25% 14% 30% 22% 7% 1	593
	21st to end	Night	21% 11% 31% 27% 9% 1	600
May	1st to 10th	Night	19% 9% 31% 32% 8% 1	600
	11th to 20th	Night	18% 9% 34% 29% 9% 1	591
	21st to end	Night	15% 9% 26% 34% 15% 1	650
June	1st to 10th	Night	15% 7% 30% 35% 12% 1	600
	11th to 20th	Night	15% 8% 26% 37% 13% 2	600
	21st to end	Night	14% 5% 29% 37% 16% 1	600
July	1st to 10th	Night	11% 4 21% 41% 21% 2	585
	11th to 20th	Night	10% 4 25% 35% 24% 2	582
	21st to end	Night	9% 4 26% 36% 22% 2	657
August	1st to 10th	Night	10% 3 20% 39% 26% 1	597
	11th to 20th	Night	11% 7% 20% 34% 25% 4	594
	21st to end	Night	15% 5% 23% 38% 18% 2	660
September	1st to 10th	Night	15% 8% 24% 30% 19% 4	600
	11th to 20th	Night	15% 6% 23% 32% 22% 3	779
	21st to end	Night	21% 8% 21% 30% 18% 2	800
October	1st to 10th	Night	23% 12% 24% 27% 12% 1	800
	11th to 20th	Night	33% 14% 26% 21% 6%	800
	21st to end	Night	33% 16% 24% 20% 6% 1	880
November	1st to 10th	Night	31% 14% 32% 20% 3	820
	11th to 20th	Night	29% 23% 28% 17% 3	840
	21st to end	Night	30% 21% 30% 16% 2	924
December	1st to 10th	Night	30% 24% 30% 14% 3	1050
	11th to 20th	Night	28% 24% 28% 15% 3 1	1050
	21st to end	Night	31% 21% 32% 15% 2	1155

Page generated at 2026-02-13 01:42:13. Version ac07

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