Richville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Richville clear sky chart from 2005-11-06 to 2024-11-11.

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	12% 9% 3 8% 5% 5% 5% 4 6% 7% 36%	101715
	Night	11% 9% 4 9% 6% 5% 5% 4 6% 7% 35%	97547
Transparency	Day	45% 7% 13% 25% 10% 1	105277
	Night	46% 6% 12% 24% 11% 1	102130
Seeing	Day	15% 9% 30% 28% 15% 3	16117
	Night	15% 9% 33% 32% 11% 1	26010

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	7% 15% 6% 14% 9% 8% 7% 4 6% 6% 18%	2218
	11th to 20th	Day	5% 9% 4 15% 8% 9% 13% 8% 8% 6% 15%	2348
	21st to end	Day	6% 13% 11% 19% 8% 8% 5% 4 5% 6% 15%	3055
February	1st to 10th	Day	7% 13% 6% 12% 7% 6% 7% 5% 8% 6% 23%	1710
	11th to 20th	Day	7% 11% 4 9% 8% 8% 6% 5% 6% 8% 28%	1664
	21st to end	Day	8% 11% 4 11% 9% 7% 7% 6% 6% 6% 25%	1470
March	1st to 10th	Day	11% 13% 4 10% 6% 5% 4 3 5% 6% 34%	3343
	11th to 20th	Day	8% 10% 4 9% 7% 4 5% 4 6% 8% 35%	3480
	21st to end	Day	19% 13% 4 11% 8% 5% 5% 4 5% 6% 21%	3814
April	1st to 10th	Day	15% 10% 5% 7% 5% 4 5% 4 5% 6% 33%	2218
	11th to 20th	Day	16% 13% 3 9% 4 4 4 3 6% 6% 31%	2434
	21st to end	Day	21% 10% 3 7% 5% 4 4 3 5% 6% 33%	2470
May	1st to 10th	Day	17% 8% 3 6% 5% 5% 4 4 5% 8% 37%	4136
	11th to 20th	Day	14% 7% 2 6% 4 4 4 4 6% 8% 41%	4399
	21st to end	Day	18% 6% 3 6% 5% 5% 4 4 5% 8% 36%	4907
June	1st to 10th	Day	11% 6% 2 5% 4 5% 5% 4 6% 8% 43%	2850
	11th to 20th	Day	14% 7% 2 6% 5% 4 4 4 6% 7% 40%	2850
	21st to end	Day	10% 6% 2 5% 5% 5% 5% 5% 8% 10% 40%	2850
July	1st to 10th	Day	9% 4 2 6% 4 4 5% 5% 7% 10% 43%	4750
	11th to 20th	Day	6% 3 1 4 3 4 4 4 6% 9% 55%	4750
	21st to end	Day	5% 3 2 6% 4 5% 5% 4 8% 10% 49%	4733
August	1st to 10th	Day	12% 4 2 5% 3 3 4 4 7% 10% 46%	4104
	11th to 20th	Day	13% 6% 2 6% 4 4 4 3 6% 9% 43%	4041
	21st to end	Day	13% 5% 2 6% 4 3 4 3 5% 7% 48%	4532
September	1st to 10th	Day	11% 5% 2 4 3 4 4 3 6% 8% 49%	2285
	11th to 20th	Day	11% 6% 2 7% 4 5% 4 4 6% 6% 45%	2117
	21st to end	Day	13% 6% 2 6% 4 4 4 3 6% 8% 43%	2085
October	1st to 10th	Day	16% 9% 3 6% 4 5% 4 3 6% 6% 39%	1900
	11th to 20th	Day	17% 12% 3 7% 3 3 3 3 3 6% 39%	1900
	21st to end	Day	19% 12% 3 8% 4 3 3 4 5% 6% 32%	1995
November	1st to 10th	Day	14% 14% 5% 10% 4 3 5% 3 4 5% 32%	1622
	11th to 20th	Day	10% 17% 5% 15% 7% 5% 4 3 5% 4 25%	1520
	21st to end	Day	11% 11% 6% 13% 7% 6% 5% 4 6% 6% 27%	1520
December	1st to 10th	Day	8% 14% 5% 14% 9% 7% 5% 5% 6% 7% 21%	1520
	11th to 20th	Day	8% 14% 7% 12% 8% 6% 6% 5% 5% 6% 22%	1683
	21st to end	Day	20% 15% 5% 11% 7% 5% 4 3 5% 5% 20%	2442
January	1st to 10th	Night	6% 12% 5% 15% 9% 8% 7% 5% 6% 7% 20%	4737
	11th to 20th	Night	5% 11% 5% 12% 10% 10% 12% 7% 7% 6% 13%	4620
	21st to end	Night	6% 15% 11% 16% 7% 7% 6% 4 5% 6% 18%	4598
February	1st to 10th	Night	6% 10% 5% 11% 6% 6% 7% 5% 8% 8% 29%	2470
	11th to 20th	Night	6% 10% 4 9% 7% 5% 6% 5% 7% 7% 33%	2403
	21st to end	Night	10% 10% 4 9% 8% 7% 6% 5% 7% 7% 29%	2000
March	1st to 10th	Night	8% 8% 3 8% 6% 4 5% 4 6% 8% 41%	3513
	11th to 20th	Night	9% 10% 3 9% 9% 5% 5% 4 5% 6% 35%	3480
	21st to end	Night	19% 15% 5% 11% 5% 4 3 3 4 5% 27%	3817
April	1st to 10th	Night	13% 10% 3 8% 4 4 4 3 6% 6% 38%	1961
	11th to 20th	Night	18% 12% 4 8% 3 3 3 3 4 6% 37%	1694
	21st to end	Night	17% 10% 3 7% 5% 4 5% 3 4 5% 37%	1710
May	1st to 10th	Night	16% 9% 2 6% 4 3 4 3 5% 6% 40%	2769
	11th to 20th	Night	14% 6% 2 5% 4 3 4 4 6% 7% 45%	2506
	21st to end	Night	16% 9% 2 6% 5% 5% 4 4 5% 6% 39%	2655
June	1st to 10th	Night	10% 5% 2 4 3 4 4 3 6% 9% 50%	1330
	11th to 20th	Night	11% 7% 2 5% 4 2 4 3 6% 8% 46%	1330
	21st to end	Night	7% 5% 1 5% 4 3 4 4 6% 9% 51%	1330
July	1st to 10th	Night	9% 3 1 5% 5% 6% 6% 5% 7% 9% 43%	2220
	11th to 20th	Night	4 2 2 3 3 2 3 3 5% 8% 64%	2220
	21st to end	Night	6% 3 1 5% 4 5% 6% 4 7% 9% 52%	2827
August	1st to 10th	Night	9% 4 2 4 4 4 5% 3 5% 6% 54%	2836
	11th to 20th	Night	13% 4 2 5% 3 3 4 3 5% 9% 51%	2798
	21st to end	Night	12% 5% 2 6% 3 3 3 3 4 8% 51%	3135
September	1st to 10th	Night	9% 4 1 4 3 4 4 3 5% 7% 55%	1894
	11th to 20th	Night	8% 5% 2 5% 4 3 4 3 6% 8% 52%	2061
	21st to end	Night	12% 6% 2 5% 4 3 3 3 5% 6% 51%	2090
October	1st to 10th	Night	14% 8% 3 6% 3 4 4 4 6% 7% 42%	2265
	11th to 20th	Night	14% 11% 3 6% 4 4 4 3 4 7% 40%	2280
	21st to end	Night	17% 11% 3 9% 4 4 4 3 5% 6% 35%	2599
November	1st to 10th	Night	11% 12% 4 9% 5% 5% 4 3 6% 6% 35%	2676
	11th to 20th	Night	11% 13% 6% 14% 6% 4 4 3 5% 6% 28%	2667
	21st to end	Night	11% 10% 4 9% 7% 5% 5% 4 6% 6% 32%	2660
December	1st to 10th	Night	8% 12% 6% 12% 8% 7% 6% 4 6% 7% 23%	2660
	11th to 20th	Night	10% 15% 5% 13% 8% 5% 6% 3 5% 6% 23%	3511
	21st to end	Night	19% 16% 6% 11% 7% 5% 5% 4 5% 5% 17%	5225

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	66% 6% 9% 15% 4	2219
	11th to 20th	Day	64% 7% 8% 16% 4	2348
	21st to end	Day	68% 5% 9% 12% 6%	3055
February	1st to 10th	Day	56% 5% 10% 20% 9%	1710
	11th to 20th	Day	53% 6% 15% 19% 6% 2	1673
	21st to end	Day	55% 8% 10% 17% 9%	1470
March	1st to 10th	Day	51% 6% 10% 26% 7%	3343
	11th to 20th	Day	45% 5% 12% 29% 8%	3480
	21st to end	Day	63% 7% 11% 14% 4	3814
April	1st to 10th	Day	50% 6% 10% 21% 12% 1	2218
	11th to 20th	Day	52% 6% 13% 17% 11% 1	2434
	21st to end	Day	52% 6% 10% 23% 8% 1	2470
May	1st to 10th	Day	43% 7% 13% 24% 12% 1	4174
	11th to 20th	Day	38% 7% 12% 30% 11% 3	4403
	21st to end	Day	44% 7% 13% 28% 7% 1	4920
June	1st to 10th	Day	36% 8% 16% 30% 9% 1	2850
	11th to 20th	Day	42% 8% 14% 23% 13% 1	2850
	21st to end	Day	35% 9% 18% 26% 11%	2850
July	1st to 10th	Day	33% 10% 18% 27% 11% 1	4676
	11th to 20th	Day	23% 7% 19% 37% 13% 1	4669
	21st to end	Day	27% 9% 17% 35% 11% 1	4583
August	1st to 10th	Day	33% 6% 15% 32% 12% 2	4090
	11th to 20th	Day	37% 7% 15% 32% 8% 1	4080
	21st to end	Day	36% 6% 17% 29% 11% 1	4531
September	1st to 10th	Day	31% 6% 16% 35% 12% 1	2285
	11th to 20th	Day	38% 6% 16% 30% 10%	2117
	21st to end	Day	37% 6% 14% 33% 8% 2	2085
October	1st to 10th	Day	34% 4 10% 34% 18% 1	3160
	11th to 20th	Day	41% 5% 9% 24% 20% 1	3140
	21st to end	Day	51% 4 14% 24% 7%	3276
November	1st to 10th	Day	53% 6% 10% 20% 9% 1	1622
	11th to 20th	Day	62% 5% 11% 13% 8%	1520
	21st to end	Day	56% 7% 15% 15% 6% 1	1520
December	1st to 10th	Day	62% 7% 11% 15% 5%	1520
	11th to 20th	Day	61% 6% 13% 16% 4	1680
	21st to end	Day	66% 6% 7% 16% 5%	2442
January	1st to 10th	Night	62% 7% 9% 17% 5%	4737
	11th to 20th	Night	66% 8% 10% 10% 5%	4620
	21st to end	Night	65% 6% 9% 15% 5%	4598
February	1st to 10th	Night	49% 6% 12% 21% 10% 1	2470
	11th to 20th	Night	47% 6% 12% 21% 12% 1	2404
	21st to end	Night	52% 6% 12% 19% 10% 2	2000
March	1st to 10th	Night	40% 7% 15% 25% 11% 2	3513
	11th to 20th	Night	47% 6% 11% 25% 11%	3480
	21st to end	Night	61% 4 9% 19% 6% 1	3817
April	1st to 10th	Night	46% 6% 11% 22% 13% 2	1961
	11th to 20th	Night	49% 5% 8% 23% 14% 2	1694
	21st to end	Night	49% 5% 10% 23% 11% 1	1710
May	1st to 10th	Night	43% 6% 11% 26% 12% 2	2796
	11th to 20th	Night	37% 7% 10% 26% 18% 3	2507
	21st to end	Night	43% 8% 11% 25% 11% 1	2663
June	1st to 10th	Night	31% 7% 17% 33% 11% 1	1330
	11th to 20th	Night	34% 7% 15% 25% 15% 3	1330
	21st to end	Night	28% 7% 19% 29% 14% 2	1330
July	1st to 10th	Night	35% 10% 18% 23% 13% 1	2185
	11th to 20th	Night	17% 6% 15% 44% 16% 3	2178
	21st to end	Night	26% 9% 17% 34% 12% 2	2738
August	1st to 10th	Night	29% 6% 14% 32% 16% 2	2826
	11th to 20th	Night	31% 7% 16% 34% 12% 1	2825
	21st to end	Night	32% 7% 16% 30% 13% 1	3135
September	1st to 10th	Night	28% 7% 15% 34% 15% 1	1894
	11th to 20th	Night	30% 8% 17% 32% 13%	2061
	21st to end	Night	33% 5% 12% 34% 16%	2090
October	1st to 10th	Night	28% 4 8% 35% 20% 5%	3785
	11th to 20th	Night	39% 5% 9% 28% 18% 1	3779
	21st to end	Night	46% 5% 13% 25% 11%	4273
November	1st to 10th	Night	48% 7% 11% 23% 10% 2	2676
	11th to 20th	Night	57% 5% 12% 15% 9% 1	2667
	21st to end	Night	51% 7% 16% 20% 6% 1	2660
December	1st to 10th	Night	59% 6% 13% 16% 5%	2660
	11th to 20th	Night	61% 6% 13% 15% 4 1	3513
	21st to end	Night	66% 6% 9% 12% 6%	5225

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% 11% 29% 30% 12% 3	270
	11th to 20th	Day	13% 10% 31% 36% 10%	270
	21st to end	Day	12% 6% 42% 20% 16% 4	297
February	1st to 10th	Day	13% 14% 40% 26% 6% 1	270
	11th to 20th	Day	14% 13% 40% 22% 10% 1	270
	21st to end	Day	11% 9% 41% 33% 6%	225
March	1st to 10th	Day	17% 13% 34% 26% 9% 1	270
	11th to 20th	Day	14% 10% 32% 28% 12% 3	270
	21st to end	Day	19% 11% 29% 26% 12% 3	297
April	1st to 10th	Day	21% 15% 31% 23% 10%	398
	11th to 20th	Day	24% 12% 29% 22% 11% 2	632
	21st to end	Day	22% 9% 30% 21% 16% 1	650
May	1st to 10th	Day	20% 11% 31% 24% 12% 1	653
	11th to 20th	Day	16% 9% 29% 28% 15% 3	675
	21st to end	Day	18% 7% 29% 29% 14% 3	734
June	1st to 10th	Day	12% 7% 26% 31% 20% 4	680
	11th to 20th	Day	14% 10% 37% 25% 11% 2	680
	21st to end	Day	11% 8% 29% 31% 17% 3	680
July	1st to 10th	Day	7% 5% 22% 32% 29% 6%	671
	11th to 20th	Day	11% 6% 26% 29% 21% 7%	668
	21st to end	Day	6% 4 24% 33% 27% 6%	739
August	1st to 10th	Day	9% 4 21% 37% 24% 5%	676
	11th to 20th	Day	13% 5% 19% 34% 21% 8%	665
	21st to end	Day	10% 7% 27% 31% 20% 5%	748
September	1st to 10th	Day	11% 5% 31% 33% 17% 4	495
	11th to 20th	Day	10% 6% 32% 33% 13% 6%	327
	21st to end	Day	17% 13% 33% 21% 13% 3	300
October	1st to 10th	Day	20% 9% 30% 27% 13% 1	300
	11th to 20th	Day	18% 14% 35% 24% 7% 1	300
	21st to end	Day	23% 15% 36% 18% 6% 2	330
November	1st to 10th	Day	24% 10% 30% 27% 8% 1	300
	11th to 20th	Day	17% 18% 39% 20% 5%	270
	21st to end	Day	18% 16% 38% 23% 6%	270
December	1st to 10th	Day	11% 9% 43% 25% 10% 2	270
	11th to 20th	Day	18% 11% 40% 26% 5%	270
	21st to end	Day	24% 9% 33% 28% 5% 1	297
January	1st to 10th	Night	10% 12% 38% 29% 9% 2	950
	11th to 20th	Night	15% 11% 36% 30% 8% 1	950
	21st to end	Night	15% 9% 38% 29% 8% 1	1045
February	1st to 10th	Night	11% 10% 36% 33% 9% 1	950
	11th to 20th	Night	11% 9% 41% 27% 9% 2	929
	21st to end	Night	14% 8% 33% 31% 11% 3	744
March	1st to 10th	Night	15% 9% 37% 28% 9% 1	630
	11th to 20th	Night	14% 8% 42% 28% 8% 1	570
	21st to end	Night	22% 8% 28% 28% 11% 2	627
April	1st to 10th	Night	17% 9% 36% 30% 6% 1	570
	11th to 20th	Night	22% 12% 30% 25% 9% 1	563
	21st to end	Night	22% 7% 32% 27% 11% 1	570
May	1st to 10th	Night	19% 9% 31% 31% 9%	570
	11th to 20th	Night	16% 7% 34% 29% 11% 1	561
	21st to end	Night	15% 7% 32% 34% 11%	617
June	1st to 10th	Night	13% 6% 28% 36% 16% 1	570
	11th to 20th	Night	14% 5% 32% 40% 9%	570
	21st to end	Night	8% 4 28% 42% 17% 1	570
July	1st to 10th	Night	5% 3 22% 43% 24% 3	555
	11th to 20th	Night	7% 3 23% 47% 19% 2	552
	21st to end	Night	5% 2 23% 48% 20% 2	624
August	1st to 10th	Night	9% 2 18% 50% 19% 2	567
	11th to 20th	Night	11% 4 21% 39% 23% 3	564
	21st to end	Night	9% 4 28% 38% 19% 2	627
September	1st to 10th	Night	11% 5% 28% 37% 17% 1	570
	11th to 20th	Night	10% 5% 32% 36% 16% 2	570
	21st to end	Night	15% 7% 33% 32% 13% 1	570
October	1st to 10th	Night	19% 10% 31% 30% 9%	745
	11th to 20th	Night	19% 12% 33% 29% 7%	760
	21st to end	Night	22% 11% 35% 26% 5%	927
November	1st to 10th	Night	17% 11% 34% 30% 8%	975
	11th to 20th	Night	18% 13% 33% 27% 8% 1	953
	21st to end	Night	16% 14% 38% 26% 6%	950
December	1st to 10th	Night	14% 12% 36% 30% 8% 1	950
	11th to 20th	Night	17% 11% 38% 27% 7% 1	950
	21st to end	Night	25% 9% 35% 24% 7% 1	1045

Page generated at 2024-11-08 05:44:47. Version ac07

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