Riverton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Riverton clear sky chart from 2005-11-06 to 2024-11-03.

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 4 2 5% 4 4 5% 4 7% 9% 53%	101531
	Night	4 6% 2 6% 4 4 5% 4 7% 9% 50%	97717
Transparency	Day	24% 6% 13% 26% 21% 9%	101282
	Night	27% 7% 15% 27% 18% 7%	97556
Seeing	Day	6% 6% 21% 35% 24% 8%	15729
	Night	6% 4 25% 46% 18% 1	25791

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 4 2 9% 6% 6% 6% 6% 12% 13% 34%	2538
	11th to 20th	Day	1 5% 3 8% 5% 6% 5% 6% 8% 12% 42%	2728
	21st to end	Day	1 3 2 6% 4 4 7% 8% 11% 14% 39%	3146
February	1st to 10th	Day	2 7% 3 7% 6% 5% 6% 5% 8% 9% 43%	1710
	11th to 20th	Day	2 6% 3 8% 6% 4 5% 6% 8% 10% 43%	1665
	21st to end	Day	1 5% 3 5% 5% 5% 5% 4 7% 10% 49%	1494
March	1st to 10th	Day	1 3 2 5% 3 4 5% 5% 8% 12% 53%	3400
	11th to 20th	Day	2 6% 2 6% 4 4 5% 4 6% 9% 54%	3490
	21st to end	Day	6% 8% 3 7% 5% 6% 6% 5% 8% 11% 36%	3842
April	1st to 10th	Day	6% 7% 2 5% 4 4 5% 5% 6% 10% 47%	2280
	11th to 20th	Day	5% 8% 3 7% 5% 5% 5% 4 7% 8% 42%	2251
	21st to end	Day	9% 8% 3 6% 6% 5% 5% 5% 7% 8% 39%	2437
May	1st to 10th	Day	8% 11% 3 8% 5% 5% 5% 4 6% 7% 36%	4160
	11th to 20th	Day	9% 5% 2 4 3 3 4 3 6% 9% 52%	4388
	21st to end	Day	7% 5% 1 4 3 4 5% 5% 7% 10% 48%	4825
June	1st to 10th	Day	4 3 2 4 4 3 6% 4 7% 10% 53%	2660
	11th to 20th	Day	5% 3 2 4 3 3 4 4 6% 8% 59%	2660
	21st to end	Day	2 3 1 3 3 3 4 4 6% 8% 65%	2660
July	1st to 10th	Day	2 2 1 2 2 2 3 3 6% 8% 70%	4430
	11th to 20th	Day	1 2 1 3 2 3 4 4 7% 9% 64%	4430
	21st to end	Day	2 2 1 3 3 4 4 4 7% 9% 61%	4559
August	1st to 10th	Day	3 2 1 3 3 4 5% 5% 7% 9% 57%	4092
	11th to 20th	Day	2 2 1 3 2 3 5% 4 7% 9% 61%	4028
	21st to end	Day	1 2 1 2 2 2 3 3 5% 7% 71%	4278
September	1st to 10th	Day	3 3 1 3 3 4 4 3 5% 6% 64%	2280
	11th to 20th	Day	5% 2 1 3 3 2 3 3 5% 7% 66%	2237
	21st to end	Day	6% 3 1 4 2 2 3 2 5% 5% 67%	2024
October	1st to 10th	Day	9% 6% 2 4 3 3 3 3 5% 6% 56%	1900
	11th to 20th	Day	6% 5% 1 4 3 4 3 3 4 7% 60%	1900
	21st to end	Day	4 5% 2 6% 4 3 4 3 5% 9% 55%	2090
November	1st to 10th	Day	2 4 1 5% 3 4 4 5% 6% 9% 57%	1669
	11th to 20th	Day	1 4 2 4 4 4 6% 5% 7% 9% 53%	1520
	21st to end	Day	2 7% 3 6% 4 3 5% 5% 5% 10% 51%	1520
December	1st to 10th	Day	2 4 3 6% 4 4 5% 5% 8% 12% 45%	1520
	11th to 20th	Day	2 5% 2 3 4 4 6% 5% 9% 12% 49%	1926
	21st to end	Day	1 7% 3 6% 4 5% 5% 5% 11% 15% 39%	2794
January	1st to 10th	Night	1 7% 3 7% 5% 6% 7% 6% 10% 13% 36%	4417
	11th to 20th	Night	1 4 3 10% 5% 4 6% 5% 10% 13% 39%	4270
	21st to end	Night	1 6% 2 7% 5% 6% 8% 8% 10% 13% 34%	4521
February	1st to 10th	Night	2 7% 3 8% 5% 4 6% 4 7% 9% 44%	2470
	11th to 20th	Night	2 5% 3 7% 5% 5% 6% 5% 7% 9% 44%	2402
	21st to end	Night	2 7% 4 7% 5% 4 4 4 7% 8% 49%	1960
March	1st to 10th	Night	2 8% 2 6% 3 4 4 4 5% 9% 54%	3471
	11th to 20th	Night	3 8% 3 6% 3 3 4 3 5% 8% 52%	3490
	21st to end	Night	4 9% 3 9% 5% 5% 6% 5% 8% 10% 37%	3808
April	1st to 10th	Night	7% 8% 2 5% 4 4 4 4 5% 8% 48%	1900
	11th to 20th	Night	8% 9% 3 7% 5% 5% 5% 4 7% 8% 40%	1877
	21st to end	Night	9% 10% 3 6% 4 4 4 4 6% 8% 43%	1739
May	1st to 10th	Night	13% 11% 3 8% 4 5% 4 3 5% 6% 38%	2809
	11th to 20th	Night	10% 6% 2 5% 3 3 4 3 6% 8% 49%	2517
	21st to end	Night	10% 5% 2 4 4 4 4 4 6% 8% 48%	2762
June	1st to 10th	Night	4 4 1 4 4 4 4 4 7% 9% 55%	1520
	11th to 20th	Night	8% 4 1 4 3 3 4 3 5% 8% 56%	1520
	21st to end	Night	3 3 1 4 2 2 3 3 6% 7% 66%	1520
July	1st to 10th	Night	2 1 1 3 3 3 3 3 7% 8% 65%	2540
	11th to 20th	Night	1 1 1 2 2 3 4 4 7% 9% 66%	2540
	21st to end	Night	2 2 1 2 2 3 3 3 6% 11% 65%	3000
August	1st to 10th	Night	4 3 1 4 3 4 3 4 6% 7% 60%	2847
	11th to 20th	Night	2 2 1 4 4 4 5% 5% 7% 8% 60%	2811
	21st to end	Night	1 2 1 2 2 2 3 3 4 9% 69%	3387
September	1st to 10th	Night	4 3 1 4 3 3 4 4 4 7% 64%	1900
	11th to 20th	Night	5% 3 2 3 3 3 3 4 6% 6% 62%	1940
	21st to end	Night	7% 3 1 3 2 3 2 2 4 6% 67%	2155
October	1st to 10th	Night	10% 7% 2 4 4 3 4 3 5% 6% 53%	2280
	11th to 20th	Night	6% 4 2 5% 3 3 3 3 4 7% 59%	2280
	21st to end	Night	5% 7% 2 6% 3 3 4 3 5% 8% 54%	2508
November	1st to 10th	Night	3 4 2 5% 4 3 4 5% 7% 9% 54%	2432
	11th to 20th	Night	3 5% 2 5% 5% 5% 5% 5% 7% 8% 51%	2660
	21st to end	Night	3 7% 3 6% 4 4 4 3 6% 8% 52%	2660
December	1st to 10th	Night	2 6% 3 7% 5% 4 4 4 7% 9% 50%	2660
	11th to 20th	Night	1 6% 3 6% 4 4 5% 5% 9% 14% 44%	3271
	21st to end	Night	2 7% 3 7% 4 5% 5% 6% 10% 15% 37%	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	31% 8% 18% 31% 11% 1	2539
	11th to 20th	Day	30% 10% 21% 25% 12% 1	2728
	21st to end	Day	22% 13% 27% 27% 9% 1	3146
February	1st to 10th	Day	33% 7% 19% 30% 10% 1	1710
	11th to 20th	Day	31% 7% 20% 26% 13% 2	1674
	21st to end	Day	28% 5% 20% 28% 17% 2	1494
March	1st to 10th	Day	19% 5% 15% 38% 19% 4	3400
	11th to 20th	Day	25% 7% 22% 33% 14% 1	3490
	21st to end	Day	36% 9% 18% 30% 6%	3842
April	1st to 10th	Day	31% 7% 19% 27% 14% 2	2280
	11th to 20th	Day	35% 7% 15% 27% 15% 1	2254
	21st to end	Day	39% 7% 12% 26% 15% 1	2437
May	1st to 10th	Day	40% 7% 14% 20% 13% 5%	4160
	11th to 20th	Day	27% 7% 12% 30% 20% 4	4392
	21st to end	Day	26% 7% 15% 32% 18% 3	4825
June	1st to 10th	Day	23% 7% 17% 27% 20% 5%	2660
	11th to 20th	Day	21% 6% 13% 21% 26% 13%	2660
	21st to end	Day	15% 5% 9% 24% 29% 18%	2660
July	1st to 10th	Day	12% 4 7% 20% 35% 23%	4361
	11th to 20th	Day	14% 4 5% 17% 33% 27%	4355
	21st to end	Day	17% 4 6% 16% 31% 26%	4415
August	1st to 10th	Day	21% 5% 8% 23% 24% 19%	4078
	11th to 20th	Day	18% 5% 6% 22% 33% 16%	4067
	21st to end	Day	13% 4 6% 19% 35% 24%	4277
September	1st to 10th	Day	20% 4 8% 18% 31% 18%	2280
	11th to 20th	Day	18% 4 8% 27% 27% 16%	2237
	21st to end	Day	19% 4 7% 28% 33% 9%	2024
October	1st to 10th	Day	28% 6% 10% 27% 21% 7%	1900
	11th to 20th	Day	25% 5% 12% 34% 20% 5%	1900
	21st to end	Day	26% 5% 16% 30% 20% 3	2090
November	1st to 10th	Day	23% 6% 17% 29% 21% 4	1669
	11th to 20th	Day	23% 8% 18% 30% 18% 4	1520
	21st to end	Day	28% 6% 17% 29% 18% 2	1520
December	1st to 10th	Day	28% 9% 21% 26% 15% 2	1520
	11th to 20th	Day	22% 9% 24% 35% 9% 1	1924
	21st to end	Day	28% 6% 16% 32% 16% 1	2794
January	1st to 10th	Night	32% 9% 22% 28% 8% 1	4417
	11th to 20th	Night	29% 12% 23% 20% 14% 3	4270
	21st to end	Night	28% 13% 27% 23% 8% 1	4521
February	1st to 10th	Night	33% 8% 19% 29% 11% 1	2470
	11th to 20th	Night	31% 9% 17% 28% 13% 2	2403
	21st to end	Night	31% 6% 18% 25% 19% 2	1960
March	1st to 10th	Night	26% 5% 12% 35% 16% 6%	3471
	11th to 20th	Night	28% 5% 20% 34% 12% 1	3490
	21st to end	Night	38% 9% 20% 26% 6% 1	3808
April	1st to 10th	Night	33% 6% 16% 26% 14% 4	1900
	11th to 20th	Night	40% 7% 14% 23% 14% 1	1877
	21st to end	Night	37% 6% 11% 30% 15% 1	1739
May	1st to 10th	Night	43% 5% 13% 20% 16% 3	2809
	11th to 20th	Night	30% 6% 14% 27% 16% 7%	2518
	21st to end	Night	30% 5% 12% 38% 13% 1	2762
June	1st to 10th	Night	22% 8% 19% 26% 19% 6%	1520
	11th to 20th	Night	25% 6% 10% 19% 26% 14%	1520
	21st to end	Night	15% 6% 8% 19% 31% 21%	1520
July	1st to 10th	Night	15% 4 9% 19% 36% 17%	2500
	11th to 20th	Night	13% 4 6% 18% 33% 26%	2492
	21st to end	Night	12% 3 5% 20% 37% 23%	2906
August	1st to 10th	Night	21% 5% 8% 29% 17% 21%	2838
	11th to 20th	Night	21% 5% 8% 26% 26% 15%	2838
	21st to end	Night	13% 4 9% 22% 25% 28%	3387
September	1st to 10th	Night	20% 5% 8% 17% 31% 20%	1900
	11th to 20th	Night	20% 6% 9% 22% 29% 15%	1940
	21st to end	Night	20% 4 8% 26% 31% 12%	2155
October	1st to 10th	Night	31% 6% 10% 25% 20% 8%	2280
	11th to 20th	Night	26% 4 10% 31% 22% 6%	2280
	21st to end	Night	28% 5% 12% 31% 20% 4	2508
November	1st to 10th	Night	24% 7% 16% 29% 20% 4	2432
	11th to 20th	Night	29% 6% 14% 33% 15% 3	2660
	21st to end	Night	29% 6% 15% 30% 17% 2	2660
December	1st to 10th	Night	29% 6% 19% 27% 15% 3	2660
	11th to 20th	Night	26% 9% 21% 33% 10% 1	3272
	21st to end	Night	30% 8% 16% 28% 15% 3	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	5% 3 20% 45% 21% 6%	270
	11th to 20th	Day	3 4 19% 44% 23% 5%	270
	21st to end	Day	4 3 17% 48% 21% 6%	297
February	1st to 10th	Day	3 4 37% 43% 11% 2	270
	11th to 20th	Day	2 3 28% 48% 16% 2	270
	21st to end	Day	2 7% 23% 48% 18% 2	225
March	1st to 10th	Day	7% 9% 28% 41% 14% 2	427
	11th to 20th	Day	7% 9% 29% 38% 15% 2	460
	21st to end	Day	10% 12% 28% 32% 15% 2	506
April	1st to 10th	Day	9% 15% 26% 32% 15% 3	460
	11th to 20th	Day	11% 16% 30% 30% 12% 1	452
	21st to end	Day	14% 14% 21% 27% 20% 4	460
May	1st to 10th	Day	14% 14% 23% 28% 17% 5%	487
	11th to 20th	Day	15% 6% 17% 32% 24% 6%	675
	21st to end	Day	13% 5% 21% 26% 24% 11%	734
June	1st to 10th	Day	4 6% 22% 28% 29% 11%	680
	11th to 20th	Day	7% 8% 24% 34% 22% 5%	680
	21st to end	Day	3 5% 18% 39% 29% 7%	680
July	1st to 10th	Day	3 3 14% 34% 35% 12%	671
	11th to 20th	Day	3 2 14% 38% 34% 9%	668
	21st to end	Day	3 3 15% 33% 33% 13%	597
August	1st to 10th	Day	4 4 15% 36% 29% 13%	487
	11th to 20th	Day	3 3 16% 32% 32% 14%	477
	21st to end	Day	3 4 17% 32% 30% 14%	539
September	1st to 10th	Day	5% 4 17% 33% 28% 14%	490
	11th to 20th	Day	5% 8% 20% 28% 27% 13%	490
	21st to end	Day	8% 6% 16% 28% 28% 13%	424
October	1st to 10th	Day	10% 6% 12% 28% 27% 16%	300
	11th to 20th	Day	6% 7% 21% 30% 25% 11%	300
	21st to end	Day	8% 5% 22% 40% 21% 4	330
November	1st to 10th	Day	5% 6% 24% 41% 17% 7%	276
	11th to 20th	Day	4 4 23% 42% 20% 6%	270
	21st to end	Day	6% 3 21% 43% 22% 4	270
December	1st to 10th	Day	3 2 19% 52% 19% 5%	270
	11th to 20th	Day	7% 2 22% 48% 18% 4	270
	21st to end	Day	4 5% 21% 48% 14% 8%	297
January	1st to 10th	Night	3 3 28% 48% 16% 2	950
	11th to 20th	Night	3 4 32% 45% 13% 3	855
	21st to end	Night	5% 3 25% 51% 14% 1	836
February	1st to 10th	Night	5% 4 35% 44% 11% 1	760
	11th to 20th	Night	3 3 30% 48% 13% 2	744
	21st to end	Night	4 5% 35% 46% 10%	628
March	1st to 10th	Night	5% 4 33% 45% 13% 1	760
	11th to 20th	Night	5% 3 31% 47% 13%	760
	21st to end	Night	7% 5% 32% 43% 12% 1	828
April	1st to 10th	Night	12% 7% 33% 40% 8% 1	570
	11th to 20th	Night	13% 6% 30% 40% 11%	563
	21st to end	Night	12% 7% 26% 41% 13% 1	570
May	1st to 10th	Night	14% 5% 23% 37% 19% 1	570
	11th to 20th	Night	14% 4 19% 37% 24% 1	561
	21st to end	Night	12% 4 20% 39% 23% 1	617
June	1st to 10th	Night	5% 4 23% 39% 26% 3	570
	11th to 20th	Night	9% 3 25% 48% 14%	570
	21st to end	Night	4 3 15% 51% 26% 1	570
July	1st to 10th	Night	3 1 14% 48% 32% 1	555
	11th to 20th	Night	2 1 16% 55% 25% 1	552
	21st to end	Night	3 1 11% 51% 33% 2	624
August	1st to 10th	Night	3 1 13% 50% 32% 1	567
	11th to 20th	Night	2 1 13% 50% 31% 1	564
	21st to end	Night	3 2 15% 45% 34% 1	627
September	1st to 10th	Night	6% 2 16% 47% 26% 3	570
	11th to 20th	Night	5% 2 20% 44% 26% 3	610
	21st to end	Night	9% 3 16% 40% 27% 5%	760
October	1st to 10th	Night	13% 3 20% 41% 21% 3	760
	11th to 20th	Night	8% 4 24% 43% 21% 2	760
	21st to end	Night	8% 4 24% 48% 15% 1	836
November	1st to 10th	Night	4 5% 30% 47% 14% 1	879
	11th to 20th	Night	5% 6% 31% 45% 11% 1	950
	21st to end	Night	6% 3 27% 48% 15% 1	950
December	1st to 10th	Night	4 3 31% 49% 12% 1	950
	11th to 20th	Night	5% 4 30% 50% 11% 1	950
	21st to end	Night	6% 5% 30% 46% 11% 2	1045

Page generated at 2024-10-31 01:39:21. Version ac07

Copyright © 2024 Attilla Danko.