Upper Beaver Meadows
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Upper Beaver Meadows clear sky chart from 2005-11-06 to 2024-11-04.

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 6% 3 7% 5% 5% 5% 4 7% 8% 47%	105249
	Night	2 5% 2 5% 4 4 4 4 6% 9% 58%	102505
Transparency	Day	31% 7% 14% 22% 19% 7%	104994
	Night	24% 6% 17% 27% 20% 6%	102350
Seeing	Day	20% 23% 28% 19% 8% 2	15621
	Night	17% 25% 25% 21% 10% 2	25630

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	2 3 10% 5% 4 4 3 7% 8% 54%	2538
	11th to 20th	Day	3 2 9% 6% 7% 6% 5% 7% 9% 46%	2634
	21st to end	Day	5% 5% 10% 4 4 4 3 5% 8% 52%	3146
February	1st to 10th	Day	1 4 4 8% 5% 5% 5% 4 7% 9% 49%	1710
	11th to 20th	Day	4 2 6% 5% 4 5% 4 7% 10% 53%	1780
	21st to end	Day	4 4 9% 4 5% 4 5% 7% 11% 47%	1570
March	1st to 10th	Day	6% 4 11% 6% 5% 5% 5% 6% 6% 46%	3148
	11th to 20th	Day	1 9% 8% 11% 4 5% 4 4 6% 9% 40%	3490
	21st to end	Day	1 8% 4 9% 5% 4 5% 5% 6% 10% 42%	4027
April	1st to 10th	Day	2 8% 3 5% 4 5% 5% 4 6% 11% 47%	2280
	11th to 20th	Day	4 13% 5% 8% 4 5% 5% 4 7% 8% 36%	2251
	21st to end	Day	5% 12% 3 9% 6% 5% 6% 5% 7% 9% 35%	2280
May	1st to 10th	Day	5% 15% 4 7% 5% 5% 6% 5% 7% 8% 31%	4091
	11th to 20th	Day	6% 10% 3 7% 5% 6% 6% 5% 8% 8% 36%	4388
	21st to end	Day	4 5% 2 5% 4 5% 6% 5% 8% 9% 45%	4825
June	1st to 10th	Day	4 6% 2 5% 6% 5% 6% 6% 8% 10% 43%	2660
	11th to 20th	Day	5% 6% 2 5% 4 4 5% 5% 7% 8% 50%	2660
	21st to end	Day	3 5% 2 6% 5% 5% 6% 6% 7% 8% 46%	2660
July	1st to 10th	Day	4 5% 2 6% 5% 5% 6% 5% 7% 8% 47%	4430
	11th to 20th	Day	3 4 2 7% 6% 7% 8% 6% 8% 9% 39%	4430
	21st to end	Day	5% 5% 3 7% 6% 6% 7% 6% 7% 8% 42%	4691
August	1st to 10th	Day	5% 6% 3 9% 6% 6% 7% 6% 8% 9% 34%	4092
	11th to 20th	Day	4 4 2 7% 6% 5% 6% 5% 7% 8% 45%	3797
	21st to end	Day	5% 5% 2 6% 4 4 5% 5% 7% 8% 50%	4180
September	1st to 10th	Day	6% 5% 2 6% 4 5% 5% 3 5% 7% 52%	2280
	11th to 20th	Day	6% 4 2 5% 5% 5% 4 4 6% 6% 53%	2280
	21st to end	Day	6% 5% 2 5% 4 3 3 3 5% 6% 59%	2066
October	1st to 10th	Day	2 4 1 4 3 3 3 3 4 5% 68%	3170
	11th to 20th	Day	3 5% 1 4 4 4 4 4 7% 9% 54%	3150
	21st to end	Day	3 6% 2 5% 3 3 3 2 4 7% 62%	3348
November	1st to 10th	Day	1 4 2 4 3 3 4 3 6% 7% 62%	1700
	11th to 20th	Day	1 4 2 4 4 2 3 3 6% 11% 60%	1710
	21st to end	Day	4 2 7% 5% 4 4 3 6% 8% 56%	1547
December	1st to 10th	Day	3 3 7% 4 4 4 3 6% 9% 56%	1520
	11th to 20th	Day	1 4 2 6% 4 4 5% 5% 9% 10% 51%	1926
	21st to end	Day	5% 3 11% 6% 5% 4 3 6% 8% 48%	2794
January	1st to 10th	Night	2 2 8% 6% 6% 5% 4 6% 9% 53%	4417
	11th to 20th	Night	2 1 4 5% 6% 5% 3 6% 9% 59%	4366
	21st to end	Night	5% 4 8% 3 3 4 3 5% 8% 57%	4521
February	1st to 10th	Night	4 2 6% 5% 3 4 3 6% 9% 58%	2470
	11th to 20th	Night	4 2 5% 3 4 3 4 6% 9% 59%	2287
	21st to end	Night	4 3 8% 5% 3 3 4 5% 8% 56%	1884
March	1st to 10th	Night	4 4 7% 4 3 4 3 6% 8% 57%	3713
	11th to 20th	Night	1 8% 6% 8% 3 3 3 3 4 8% 53%	3490
	21st to end	Night	1 6% 2 6% 4 4 5% 4 7% 10% 52%	3619
April	1st to 10th	Night	1 6% 3 5% 4 3 3 3 6% 8% 57%	1900
	11th to 20th	Night	3 8% 3 6% 3 3 4 4 5% 8% 51%	1877
	21st to end	Night	5% 10% 2 4 4 3 3 4 5% 9% 49%	1900
May	1st to 10th	Night	4 10% 2 5% 4 4 4 4 7% 8% 49%	2876
	11th to 20th	Night	6% 11% 2 5% 5% 5% 4 4 5% 7% 47%	2517
	21st to end	Night	3 4 1 4 4 4 5% 4 6% 7% 60%	2762
June	1st to 10th	Night	3 3 1 3 3 3 5% 4 6% 10% 58%	1520
	11th to 20th	Night	4 3 2 3 3 3 3 4 6% 8% 62%	1520
	21st to end	Night	3 3 1 4 3 4 4 6% 7% 8% 59%	1520
July	1st to 10th	Night	3 5% 2 4 3 4 4 4 6% 7% 59%	2540
	11th to 20th	Night	2 2 1 3 3 3 5% 5% 10% 11% 54%	2540
	21st to end	Night	3 5% 1 3 4 4 4 4 6% 7% 59%	2868
August	1st to 10th	Night	4 5% 2 5% 4 4 5% 5% 8% 11% 47%	2847
	11th to 20th	Night	3 3 1 4 3 4 5% 4 7% 10% 55%	3042
	21st to end	Night	2 4 2 4 3 4 5% 4 7% 9% 56%	3487
September	1st to 10th	Night	5% 5% 2 4 3 4 4 3 5% 7% 59%	1900
	11th to 20th	Night	5% 3 1 4 2 2 4 3 5% 7% 64%	1900
	21st to end	Night	5% 4 1 4 2 3 3 3 5% 6% 63%	2111
October	1st to 10th	Night	2 3 1 2 2 2 2 2 3 6% 74%	3800
	11th to 20th	Night	2 4 1 4 3 3 3 3 4 9% 63%	3778
	21st to end	Night	2 5% 2 3 2 2 3 2 4 8% 68%	4177
November	1st to 10th	Night	1 3 2 4 2 3 3 3 5% 9% 66%	2451
	11th to 20th	Night	4 2 4 3 3 2 3 7% 9% 62%	2470
	21st to end	Night	1 4 3 5% 3 3 3 4 6% 8% 59%	2631
December	1st to 10th	Night	3 1 5% 3 3 3 3 5% 10% 64%	2660
	11th to 20th	Night	1 4 3 6% 4 4 3 3 7% 12% 53%	3271
	21st to end	Night	5% 3 9% 5% 4 4 4 6% 8% 52%	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	27% 6% 25% 19% 19% 3	2539
	11th to 20th	Day	32% 9% 27% 19% 11% 3	2634
	21st to end	Day	31% 5% 17% 26% 16% 5%	3146
February	1st to 10th	Day	34% 6% 22% 19% 16% 3	1710
	11th to 20th	Day	28% 4 18% 27% 17% 5%	1789
	21st to end	Day	32% 5% 17% 23% 17% 5%	1570
March	1st to 10th	Day	36% 3 15% 24% 19% 3	3148
	11th to 20th	Day	37% 9% 14% 27% 11% 2	3490
	21st to end	Day	36% 7% 19% 28% 9% 1	4027
April	1st to 10th	Day	33% 5% 17% 23% 17% 6%	2280
	11th to 20th	Day	43% 5% 16% 19% 15% 2	2254
	21st to end	Day	44% 5% 13% 25% 11% 1	2280
May	1st to 10th	Day	46% 5% 14% 17% 16% 2	4091
	11th to 20th	Day	40% 8% 13% 24% 14% 2	4392
	21st to end	Day	30% 6% 13% 21% 26% 4	4825
June	1st to 10th	Day	32% 9% 16% 21% 16% 6%	2660
	11th to 20th	Day	29% 8% 13% 17% 24% 11%	2660
	21st to end	Day	30% 8% 10% 21% 21% 10%	2660
July	1st to 10th	Day	27% 10% 10% 13% 19% 20%	4361
	11th to 20th	Day	30% 13% 12% 18% 17% 10%	4355
	21st to end	Day	32% 12% 12% 15% 14% 15%	4543
August	1st to 10th	Day	36% 15% 16% 16% 11% 7%	4078
	11th to 20th	Day	31% 12% 12% 16% 21% 9%	3834
	21st to end	Day	29% 8% 13% 16% 23% 11%	4179
September	1st to 10th	Day	29% 6% 8% 19% 25% 12%	2280
	11th to 20th	Day	29% 7% 9% 20% 25% 10%	2280
	21st to end	Day	26% 4 8% 26% 30% 6%	2066
October	1st to 10th	Day	18% 4 8% 22% 35% 13%	3170
	11th to 20th	Day	22% 9% 12% 34% 20% 4	3150
	21st to end	Day	22% 4 10% 35% 25% 4	3348
November	1st to 10th	Day	21% 5% 16% 27% 29% 4	1700
	11th to 20th	Day	20% 5% 19% 29% 21% 5%	1710
	21st to end	Day	26% 4 14% 30% 18% 8%	1547
December	1st to 10th	Day	27% 6% 24% 26% 14% 4	1520
	11th to 20th	Day	26% 7% 16% 33% 16% 1	1924
	21st to end	Day	33% 5% 14% 22% 20% 7%	2794
January	1st to 10th	Night	28% 5% 23% 27% 14% 3	4417
	11th to 20th	Night	21% 6% 29% 25% 12% 6%	4366
	21st to end	Night	26% 8% 20% 25% 16% 6%	4521
February	1st to 10th	Night	24% 7% 23% 25% 18% 3	2470
	11th to 20th	Night	22% 6% 21% 31% 18% 3	2288
	21st to end	Night	27% 5% 17% 26% 19% 6%	1884
March	1st to 10th	Night	25% 4 18% 27% 20% 7%	3713
	11th to 20th	Night	30% 5% 16% 31% 15% 3	3490
	21st to end	Night	26% 6% 24% 31% 12% 2	3619
April	1st to 10th	Night	27% 5% 19% 26% 17% 6%	1900
	11th to 20th	Night	31% 5% 18% 28% 16% 3	1877
	21st to end	Night	32% 6% 16% 29% 17%	1900
May	1st to 10th	Night	32% 6% 15% 29% 16% 3	2876
	11th to 20th	Night	35% 7% 14% 29% 14% 1	2518
	21st to end	Night	23% 5% 17% 27% 25% 4	2762
June	1st to 10th	Night	22% 8% 20% 28% 16% 6%	1520
	11th to 20th	Night	19% 6% 12% 23% 26% 13%	1520
	21st to end	Night	20% 7% 12% 26% 24% 12%	1520
July	1st to 10th	Night	23% 7% 10% 18% 22% 21%	2500
	11th to 20th	Night	17% 9% 17% 30% 19% 8%	2492
	21st to end	Night	22% 7% 15% 24% 16% 16%	2778
August	1st to 10th	Night	26% 12% 22% 18% 19% 3	2838
	11th to 20th	Night	23% 10% 21% 18% 19% 9%	3071
	21st to end	Night	23% 9% 14% 21% 29% 5%	3487
September	1st to 10th	Night	25% 5% 11% 20% 27% 12%	1900
	11th to 20th	Night	20% 5% 11% 28% 25% 11%	1900
	21st to end	Night	22% 4 9% 31% 28% 7%	2111
October	1st to 10th	Night	14% 3 7% 26% 40% 10%	3800
	11th to 20th	Night	18% 5% 13% 39% 20% 5%	3778
	21st to end	Night	17% 4 12% 37% 27% 4	4177
November	1st to 10th	Night	17% 5% 16% 29% 26% 7%	2451
	11th to 20th	Night	19% 5% 17% 33% 20% 6%	2470
	21st to end	Night	23% 4 14% 32% 20% 7%	2631
December	1st to 10th	Night	19% 7% 25% 28% 16% 6%	2660
	11th to 20th	Night	25% 8% 17% 28% 20% 3	3272
	21st to end	Night	30% 7% 14% 22% 20% 7%	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	29% 28% 22% 11% 10% 1	270
	11th to 20th	Day	34% 33% 19% 10% 4	270
	21st to end	Day	24% 36% 24% 13% 3 1	297
February	1st to 10th	Day	40% 34% 19% 4 1 1	270
	11th to 20th	Day	40% 32% 19% 8% 1	270
	21st to end	Day	37% 39% 14% 9% 1	225
March	1st to 10th	Day	32% 33% 24% 8% 4	275
	11th to 20th	Day	21% 30% 32% 12% 4	460
	21st to end	Day	23% 37% 28% 9% 2	506
April	1st to 10th	Day	27% 33% 30% 7% 3	460
	11th to 20th	Day	33% 30% 25% 9% 2	452
	21st to end	Day	23% 27% 32% 12% 4 1	460
May	1st to 10th	Day	26% 26% 29% 13% 5% 1	567
	11th to 20th	Day	21% 19% 32% 19% 8% 1	675
	21st to end	Day	17% 17% 30% 25% 10% 2	734
June	1st to 10th	Day	10% 16% 32% 24% 15% 4	680
	11th to 20th	Day	13% 21% 34% 21% 9% 2	680
	21st to end	Day	10% 14% 37% 23% 12% 4	680
July	1st to 10th	Day	9% 8% 29% 31% 18% 5%	671
	11th to 20th	Day	6% 10% 33% 31% 15% 6%	668
	21st to end	Day	9% 7% 26% 35% 18% 5%	677
August	1st to 10th	Day	13% 13% 31% 30% 12% 2	487
	11th to 20th	Day	13% 12% 32% 30% 10% 3	477
	21st to end	Day	13% 13% 28% 32% 11% 4	539
September	1st to 10th	Day	11% 16% 31% 27% 14% 2	490
	11th to 20th	Day	12% 21% 36% 19% 11% 1	490
	21st to end	Day	13% 21% 29% 21% 11% 5%	305
October	1st to 10th	Day	13% 20% 29% 25% 9% 4	300
	11th to 20th	Day	24% 29% 25% 15% 5% 1	300
	21st to end	Day	29% 30% 25% 13% 3 1	330
November	1st to 10th	Day	29% 33% 20% 11% 6% 1	279
	11th to 20th	Day	27% 36% 22% 9% 4 1	270
	21st to end	Day	22% 34% 30% 11% 2	270
December	1st to 10th	Day	32% 31% 21% 12% 2 1	270
	11th to 20th	Day	30% 41% 17% 9% 2	270
	21st to end	Day	32% 35% 20% 9% 3 1	297
January	1st to 10th	Night	26% 33% 21% 14% 5% 2	950
	11th to 20th	Night	30% 35% 19% 10% 5% 1	912
	21st to end	Night	20% 40% 25% 11% 4	836
February	1st to 10th	Night	24% 41% 21% 11% 3 1	760
	11th to 20th	Night	26% 32% 28% 11% 3	744
	21st to end	Night	28% 36% 21% 12% 2	628
March	1st to 10th	Night	19% 37% 23% 13% 6%	760
	11th to 20th	Night	15% 31% 26% 21% 6%	760
	21st to end	Night	18% 32% 27% 18% 4 1	717
April	1st to 10th	Night	19% 27% 34% 17% 3	570
	11th to 20th	Night	17% 28% 26% 21% 6% 1	563
	21st to end	Night	18% 23% 28% 22% 8% 1	570
May	1st to 10th	Night	16% 19% 31% 23% 9% 2	570
	11th to 20th	Night	16% 10% 29% 30% 13% 2	561
	21st to end	Night	12% 11% 28% 29% 19% 1	617
June	1st to 10th	Night	8% 7% 28% 34% 20% 3	570
	11th to 20th	Night	6% 15% 33% 33% 12% 1	570
	21st to end	Night	6% 8% 26% 33% 23% 4	570
July	1st to 10th	Night	7% 3 18% 39% 29% 4	555
	11th to 20th	Night	3 4 23% 37% 27% 6%	552
	21st to end	Night	6% 4 13% 38% 34% 5%	624
August	1st to 10th	Night	9% 3 18% 41% 24% 5%	567
	11th to 20th	Night	5% 5% 20% 44% 21% 4	564
	21st to end	Night	4 7% 19% 36% 26% 6%	627
September	1st to 10th	Night	9% 5% 26% 36% 19% 5%	570
	11th to 20th	Night	8% 12% 28% 33% 15% 4	570
	21st to end	Night	10% 13% 29% 30% 15% 4	596
October	1st to 10th	Night	12% 22% 27% 26% 10% 2	760
	11th to 20th	Night	16% 26% 29% 21% 6% 2	760
	21st to end	Night	17% 31% 31% 13% 6% 2	869
November	1st to 10th	Night	18% 36% 26% 14% 6%	943
	11th to 20th	Night	26% 35% 27% 10% 3 1	950
	21st to end	Night	17% 36% 30% 14% 2 1	950
December	1st to 10th	Night	25% 38% 24% 11% 3	950
	11th to 20th	Night	24% 39% 22% 11% 3 1	950
	21st to end	Night	27% 35% 21% 12% 5%	1045

Page generated at 2024-11-01 20:47:51. Version ac07

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