Richland Creek Recreation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Richland Creek Recreation Area clear sky chart from 2005-11-06 to 2026-05-02.

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	11% 7% 3 6% 4 4 4 4 5% 7% 45%	131212
	Night	11% 7% 3 6% 4 3 4 3 5% 6% 48%	131524
Transparency	Day	38% 5% 10% 24% 19% 5%	134819
	Night	35% 5% 10% 24% 20% 6%	135994
Seeing	Day	18% 15% 28% 23% 13% 3	17359
	Night	16% 16% 28% 26% 13% 2	27277

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% 3 6% 4 3 4 3 4 5% 46%	5289
	11th to 20th	Day	7% 8% 3 6% 4 3 3 3 4 4 56%	5310
	21st to end	Day	17% 7% 3 5% 3 3 3 2 4 4 49%	5812
February	1st to 10th	Day	16% 10% 3 6% 5% 3 3 3 4 4 43%	1890
	11th to 20th	Day	13% 9% 3 8% 5% 4 4 3 5% 6% 41%	1927
	21st to end	Day	14% 11% 3 6% 5% 4 3 3 4 5% 41%	1809
March	1st to 10th	Day	15% 10% 3 7% 4 4 4 3 4 6% 40%	5046
	11th to 20th	Day	9% 6% 2 5% 4 3 4 3 5% 6% 52%	5090
	21st to end	Day	12% 9% 4 7% 4 4 4 3 5% 7% 40%	5583
April	1st to 10th	Day	13% 8% 3 6% 4 4 5% 4 5% 5% 43%	2496
	11th to 20th	Day	14% 9% 3 7% 4 5% 5% 3 5% 7% 40%	2494
	21st to end	Day	17% 8% 3 7% 6% 5% 4 4 5% 5% 37%	2520
May	1st to 10th	Day	16% 9% 3 8% 6% 5% 5% 4 5% 5% 33%	5569
	11th to 20th	Day	12% 8% 3 8% 5% 5% 5% 4 6% 7% 37%	5862
	21st to end	Day	18% 8% 3 7% 5% 5% 5% 4 5% 6% 33%	6434
June	1st to 10th	Day	8% 6% 2 5% 5% 5% 6% 5% 7% 8% 41%	2780
	11th to 20th	Day	5% 5% 2 7% 6% 6% 6% 5% 7% 8% 42%	2800
	21st to end	Day	4 4 2 4 5% 5% 6% 5% 8% 10% 47%	2667
July	1st to 10th	Day	7% 4 3 7% 5% 5% 6% 5% 8% 11% 37%	5900
	11th to 20th	Day	4 4 2 5% 4 4 5% 4 6% 9% 54%	5900
	21st to end	Day	7% 5% 2 7% 6% 6% 6% 5% 8% 9% 38%	6422
August	1st to 10th	Day	5% 3 2 4 4 4 4 3 5% 8% 57%	4234
	11th to 20th	Day	11% 6% 2 6% 4 4 5% 4 6% 9% 43%	3957
	21st to end	Day	5% 3 2 5% 4 5% 6% 4 7% 8% 52%	4312
September	1st to 10th	Day	11% 7% 2 6% 4 4 5% 3 4 7% 47%	2400
	11th to 20th	Day	12% 5% 2 6% 4 5% 5% 5% 5% 9% 43%	2361
	21st to end	Day	9% 6% 2 5% 4 4 4 3 6% 7% 50%	2105
October	1st to 10th	Day	7% 5% 2 6% 3 4 4 2 4 6% 56%	2000
	11th to 20th	Day	11% 6% 3 5% 3 2 3 2 3 5% 58%	2000
	21st to end	Day	19% 7% 3 4 2 3 2 3 3 3 50%	2200
November	1st to 10th	Day	11% 7% 3 4 3 2 3 2 4 5% 55%	2058
	11th to 20th	Day	8% 8% 3 6% 4 3 4 2 5% 6% 51%	2026
	21st to end	Day	13% 8% 3 6% 5% 3 3 3 5% 4 47%	1753
December	1st to 10th	Day	10% 8% 3 6% 3 3 3 3 4 4 53%	2690
	11th to 20th	Day	10% 9% 4 8% 4 3 3 3 3 5% 47%	3088
	21st to end	Day	14% 13% 4 7% 5% 4 5% 3 5% 5% 35%	4428
January	1st to 10th	Night	12% 8% 3 9% 5% 4 4 3 4 5% 44%	7634
	11th to 20th	Night	8% 5% 2 5% 3 3 3 2 3 5% 61%	7680
	21st to end	Night	17% 9% 3 7% 4 4 3 2 4 5% 43%	8402
February	1st to 10th	Night	14% 8% 4 7% 5% 4 3 3 6% 5% 41%	2730
	11th to 20th	Night	14% 8% 3 7% 4 3 4 3 5% 6% 43%	2579
	21st to end	Night	13% 8% 3 7% 4 3 3 3 4 6% 47%	2014
March	1st to 10th	Night	17% 11% 3 6% 4 4 3 3 4 4 41%	5029
	11th to 20th	Night	10% 9% 3 5% 4 3 3 3 5% 6% 50%	5090
	21st to end	Night	11% 8% 2 7% 5% 4 4 3 5% 8% 43%	5588
April	1st to 10th	Night	11% 7% 2 6% 4 4 4 3 5% 6% 48%	2122
	11th to 20th	Night	12% 8% 3 7% 4 3 3 3 5% 6% 46%	2075
	21st to end	Night	14% 8% 3 6% 3 4 4 3 6% 7% 42%	2100
May	1st to 10th	Night	16% 9% 3 7% 4 4 4 3 5% 6% 40%	4351
	11th to 20th	Night	14% 9% 3 8% 5% 4 4 4 6% 7% 36%	4053
	21st to end	Night	18% 10% 3 7% 4 4 4 3 5% 6% 37%	4443
June	1st to 10th	Night	6% 4 2 5% 3 4 4 4 6% 10% 52%	1610
	11th to 20th	Night	5% 4 1 4 3 3 4 4 7% 10% 56%	1600
	21st to end	Night	3 3 2 4 3 3 3 3 6% 9% 60%	1723
July	1st to 10th	Night	6% 4 2 6% 5% 5% 4 5% 7% 11% 44%	4078
	11th to 20th	Night	4 2 1 3 3 3 4 3 5% 9% 63%	4077
	21st to end	Night	5% 6% 2 6% 4 4 5% 4 6% 10% 49%	4449
August	1st to 10th	Night	3 2 1 3 3 3 4 4 6% 9% 61%	2926
	11th to 20th	Night	4 4 2 5% 4 4 4 4 7% 9% 54%	3092
	21st to end	Night	4 3 1 5% 3 3 4 4 5% 9% 60%	3586
September	1st to 10th	Night	7% 5% 2 4 4 4 4 3 5% 7% 55%	2000
	11th to 20th	Night	10% 6% 2 5% 3 3 4 4 5% 6% 49%	2034
	21st to end	Night	8% 6% 1 5% 3 3 3 3 5% 6% 57%	2275
October	1st to 10th	Night	6% 4 1 4 3 3 3 3 5% 7% 61%	2400
	11th to 20th	Night	11% 5% 2 4 3 3 3 3 4 4 59%	2400
	21st to end	Night	17% 7% 3 5% 2 2 3 2 3 4 52%	2640
November	1st to 10th	Night	10% 7% 2 5% 3 3 3 3 4 5% 56%	2460
	11th to 20th	Night	10% 5% 2 5% 3 3 3 3 5% 6% 55%	2589
	21st to end	Night	13% 8% 3 5% 4 4 3 3 3 6% 49%	2862
December	1st to 10th	Night	10% 8% 3 6% 3 3 3 2 4 5% 52%	4720
	11th to 20th	Night	11% 10% 3 8% 4 4 3 2 3 4 47%	5339
	21st to end	Night	17% 12% 5% 7% 4 3 4 2 4 4 37%	6774

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	41% 4 7% 25% 20% 2	5290
	11th to 20th	Day	33% 4 5% 21% 31% 6%	5310
	21st to end	Day	40% 3 5% 19% 24% 9%	5812
February	1st to 10th	Day	45% 4 10% 22% 16% 4	1890
	11th to 20th	Day	45% 4 8% 20% 19% 4	1936
	21st to end	Day	45% 4 6% 17% 19% 8%	1809
March	1st to 10th	Day	46% 3 7% 17% 13% 14%	5046
	11th to 20th	Day	31% 4 8% 20% 24% 12%	5090
	21st to end	Day	43% 4 9% 26% 17% 1	5585
April	1st to 10th	Day	42% 5% 10% 19% 21% 3	2496
	11th to 20th	Day	44% 5% 10% 19% 16% 5%	2494
	21st to end	Day	48% 6% 9% 22% 14% 2	2520
May	1st to 10th	Day	51% 6% 9% 20% 13% 1	5604
	11th to 20th	Day	44% 7% 12% 23% 13% 1	5866
	21st to end	Day	51% 6% 10% 17% 16% 2	6447
June	1st to 10th	Day	37% 9% 14% 26% 14% 1	2780
	11th to 20th	Day	35% 8% 14% 25% 15% 2	2800
	21st to end	Day	28% 8% 15% 28% 16% 4	2667
July	1st to 10th	Day	36% 8% 17% 27% 11% 2	5836
	11th to 20th	Day	26% 6% 16% 34% 16% 1	5831
	21st to end	Day	38% 6% 17% 27% 12%	6240
August	1st to 10th	Day	23% 6% 16% 32% 18% 4	4220
	11th to 20th	Day	38% 6% 16% 28% 11% 1	3995
	21st to end	Day	29% 6% 15% 34% 14% 3	4311
September	1st to 10th	Day	37% 5% 10% 23% 17% 7%	2400
	11th to 20th	Day	37% 6% 12% 21% 20% 4	2361
	21st to end	Day	32% 5% 9% 23% 27% 5%	2105
October	1st to 10th	Day	18% 3 5% 16% 37% 21%	3260
	11th to 20th	Day	20% 3 3 23% 35% 16%	3240
	21st to end	Day	33% 4 7% 30% 22% 5%	3538
November	1st to 10th	Day	33% 3 8% 25% 23% 8%	2058
	11th to 20th	Day	34% 3 7% 23% 23% 10%	2026
	21st to end	Day	41% 4 7% 20% 23% 5%	1753
December	1st to 10th	Day	35% 3 7% 28% 23% 3	2690
	11th to 20th	Day	40% 3 6% 23% 25% 3	3085
	21st to end	Day	48% 5% 9% 20% 14% 3	4428
January	1st to 10th	Night	42% 5% 7% 26% 17% 3	7635
	11th to 20th	Night	27% 4 6% 20% 33% 10%	7680
	21st to end	Night	45% 3 5% 18% 22% 6%	8402
February	1st to 10th	Night	44% 5% 8% 22% 17% 4	2730
	11th to 20th	Night	42% 4 9% 21% 19% 5%	2580
	21st to end	Night	40% 4 7% 19% 21% 9%	2014
March	1st to 10th	Night	47% 4 6% 14% 17% 13%	5029
	11th to 20th	Night	35% 4 6% 24% 19% 11%	5090
	21st to end	Night	39% 5% 10% 27% 16% 2	5588
April	1st to 10th	Night	36% 5% 11% 23% 19% 6%	2122
	11th to 20th	Night	38% 4 8% 24% 19% 7%	2075
	21st to end	Night	41% 6% 11% 25% 15% 2	2100
May	1st to 10th	Night	45% 5% 14% 24% 11% 2	4381
	11th to 20th	Night	44% 7% 14% 22% 10% 2	4054
	21st to end	Night	47% 7% 11% 19% 12% 4	4452
June	1st to 10th	Night	27% 7% 15% 31% 18% 2	1610
	11th to 20th	Night	23% 6% 14% 36% 18% 3	1600
	21st to end	Night	21% 6% 17% 29% 21% 6%	1723
July	1st to 10th	Night	32% 7% 18% 25% 16% 1	4035
	11th to 20th	Night	20% 5% 18% 39% 17% 2	4026
	21st to end	Night	30% 6% 18% 31% 14%	4320
August	1st to 10th	Night	18% 6% 19% 35% 21% 1	2916
	11th to 20th	Night	26% 6% 22% 30% 15% 1	3120
	21st to end	Night	22% 5% 15% 36% 19% 3	3586
September	1st to 10th	Night	27% 6% 10% 31% 18% 8%	2000
	11th to 20th	Night	33% 6% 11% 22% 24% 4	2034
	21st to end	Night	27% 6% 10% 22% 30% 5%	2275
October	1st to 10th	Night	15% 3 7% 15% 33% 27%	3920
	11th to 20th	Night	18% 3 4 17% 37% 20%	3899
	21st to end	Night	30% 4 6% 27% 25% 9%	4252
November	1st to 10th	Night	31% 4 8% 24% 26% 8%	2460
	11th to 20th	Night	29% 4 7% 26% 26% 9%	2589
	21st to end	Night	38% 4 8% 21% 24% 5%	2862
December	1st to 10th	Night	36% 2 8% 32% 18% 3	4720
	11th to 20th	Night	42% 3 5% 21% 22% 7%	5341
	21st to end	Night	49% 5% 7% 23% 12% 4	6774

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	28% 26% 32% 11% 3	330
	11th to 20th	Day	29% 32% 29% 9% 1	330
	21st to end	Day	28% 28% 33% 9% 2	363
February	1st to 10th	Day	32% 28% 29% 9% 2	330
	11th to 20th	Day	34% 31% 26% 8% 1	330
	21st to end	Day	38% 27% 26% 5% 3	273
March	1st to 10th	Day	30% 24% 32% 12% 2	330
	11th to 20th	Day	36% 23% 32% 8% 1	330
	21st to end	Day	27% 32% 31% 8% 2	363
April	1st to 10th	Day	26% 25% 31% 13% 5%	516
	11th to 20th	Day	26% 26% 33% 12% 4 1	532
	21st to end	Day	25% 20% 34% 16% 5% 1	540
May	1st to 10th	Day	23% 19% 37% 16% 6%	568
	11th to 20th	Day	18% 17% 33% 21% 10% 1	725
	21st to end	Day	14% 14% 36% 22% 11% 3	789
June	1st to 10th	Day	10% 8% 28% 31% 18% 5%	730
	11th to 20th	Day	7% 5% 31% 35% 19% 3	730
	21st to end	Day	4 6% 33% 35% 18% 4	730
July	1st to 10th	Day	9% 4 21% 32% 26% 7%	721
	11th to 20th	Day	5% 3 24% 35% 25% 9%	718
	21st to end	Day	8% 3 14% 36% 28% 10%	794
August	1st to 10th	Day	10% 2 18% 39% 25% 5%	726
	11th to 20th	Day	14% 2 15% 35% 26% 7%	591
	21st to end	Day	10% 2 13% 34% 30% 11%	583
September	1st to 10th	Day	13% 5% 16% 31% 28% 6%	530
	11th to 20th	Day	11% 4 18% 34% 23% 9%	491
	21st to end	Day	13% 9% 28% 29% 18% 2	330
October	1st to 10th	Day	7% 12% 32% 35% 12% 2	330
	11th to 20th	Day	14% 15% 43% 21% 6% 1	330
	21st to end	Day	33% 15% 33% 14% 4 1	363
November	1st to 10th	Day	21% 16% 40% 17% 5% 1	330
	11th to 20th	Day	19% 22% 41% 12% 4 2	330
	21st to end	Day	28% 23% 30% 15% 4	330
December	1st to 10th	Day	24% 30% 28% 12% 4 2	330
	11th to 20th	Day	25% 31% 30% 11% 3	330
	21st to end	Day	27% 26% 34% 10% 2	363
January	1st to 10th	Night	20% 24% 34% 18% 3	1050
	11th to 20th	Night	21% 28% 31% 16% 3	1050
	21st to end	Night	20% 24% 35% 19% 3	1155
February	1st to 10th	Night	23% 26% 32% 18% 2	1050
	11th to 20th	Night	25% 27% 33% 14% 2	945
	21st to end	Night	25% 26% 31% 17% 1	630
March	1st to 10th	Night	24% 21% 30% 22% 3	630
	11th to 20th	Night	26% 19% 31% 21% 3	630
	21st to end	Night	21% 22% 34% 17% 6%	693
April	1st to 10th	Night	18% 23% 32% 23% 4	630
	11th to 20th	Night	20% 21% 29% 24% 7%	623
	21st to end	Night	17% 20% 36% 20% 7% 1	630
May	1st to 10th	Night	13% 16% 37% 28% 7%	603
	11th to 20th	Night	18% 12% 28% 26% 15% 1	591
	21st to end	Night	12% 10% 28% 28% 18% 4	650
June	1st to 10th	Night	8% 6% 21% 35% 29% 3	600
	11th to 20th	Night	6% 4 26% 38% 24% 3	600
	21st to end	Night	4 4 22% 40% 27% 4	600
July	1st to 10th	Night	5% 3 16% 34% 35% 8%	585
	11th to 20th	Night	5% 2 16% 35% 35% 6%	582
	21st to end	Night	5% 2 12% 39% 35% 7%	657
August	1st to 10th	Night	6% 1 15% 38% 35% 5%	597
	11th to 20th	Night	9% 2 15% 38% 31% 6%	594
	21st to end	Night	8% 2 12% 39% 33% 7%	660
September	1st to 10th	Night	10% 2 13% 36% 35% 4	600
	11th to 20th	Night	14% 2 14% 36% 26% 8%	600
	21st to end	Night	11% 5% 21% 30% 30% 3	675
October	1st to 10th	Night	8% 7% 25% 31% 26% 3	800
	11th to 20th	Night	15% 14% 30% 30% 11%	800
	21st to end	Night	22% 16% 31% 22% 8% 1	880
November	1st to 10th	Night	13% 17% 35% 24% 10%	820
	11th to 20th	Night	16% 17% 33% 27% 7%	840
	21st to end	Night	20% 24% 29% 20% 7%	972
December	1st to 10th	Night	22% 18% 35% 20% 5%	1050
	11th to 20th	Night	19% 21% 32% 22% 5%	1050
	21st to end	Night	23% 23% 31% 20% 3	1155

Page generated at 2026-04-29 01:21:42. Version ac07

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