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 2024-03-23.

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 6% 3 6% 6% 4 5% 5% 6% 9% 46%	78789
	Night	2 4 2 5% 4 3 4 4 6% 9% 57%	81170
Transparency	Day	34% 6% 15% 22% 17% 5%	78496
	Night	25% 6% 17% 27% 19% 6%	80985
Seeing	Day	20% 22% 28% 19% 9% 2	14678
	Night	17% 25% 24% 21% 10% 2	24906

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 8% 7% 3 4 4 6% 9% 54%	2538
	11th to 20th	Day	2 2 7% 8% 5% 8% 6% 7% 10% 46%	2634
	21st to end	Day	4 5% 9% 5% 3 4 4 4 8% 53%	3146
February	1st to 10th	Day	1 4 4 7% 6% 4 5% 4 7% 9% 50%	1710
	11th to 20th	Day	3 2 5% 5% 3 5% 5% 7% 11% 53%	1780
	21st to end	Day	4 4 8% 6% 4 5% 5% 6% 11% 47%	1570
March	1st to 10th	Day	1 6% 3 8% 5% 4 6% 6% 6% 8% 48%	1905
	11th to 20th	Day	2 8% 5% 7% 5% 3 4 5% 5% 10% 45%	2090
	21st to end	Day	2 9% 5% 7% 5% 4 5% 6% 7% 11% 40%	2313
April	1st to 10th	Day	2 8% 3 5% 5% 3 6% 5% 6% 11% 46%	2160
	11th to 20th	Day	5% 12% 5% 7% 5% 3 5% 5% 7% 8% 36%	2131
	21st to end	Day	5% 11% 4 7% 8% 3 6% 6% 6% 9% 35%	2160
May	1st to 10th	Day	8% 12% 4 7% 6% 4 6% 5% 6% 8% 33%	2315
	11th to 20th	Day	10% 13% 4 5% 7% 4 5% 5% 6% 8% 33%	2478
	21st to end	Day	8% 8% 4 6% 6% 5% 7% 6% 7% 9% 34%	2724
June	1st to 10th	Day	4 5% 3 5% 6% 4 6% 7% 7% 10% 43%	2520
	11th to 20th	Day	6% 5% 3 4 5% 3 5% 6% 7% 8% 50%	2520
	21st to end	Day	3 4 2 5% 6% 4 6% 7% 7% 9% 46%	2520
July	1st to 10th	Day	6% 5% 2 6% 7% 4 6% 7% 7% 9% 40%	2520
	11th to 20th	Day	4 4 3 6% 7% 4 7% 6% 8% 9% 43%	2520
	21st to end	Day	6% 6% 4 7% 7% 5% 7% 7% 8% 8% 34%	2684
August	1st to 10th	Day	8% 7% 4 8% 7% 4 7% 6% 7% 8% 34%	2328
	11th to 20th	Day	7% 5% 2 7% 8% 4 6% 5% 6% 7% 44%	2170
	21st to end	Day	6% 7% 3 7% 6% 4 6% 6% 7% 8% 40%	2376
September	1st to 10th	Day	6% 5% 2 5% 5% 4 5% 4 5% 7% 52%	2160
	11th to 20th	Day	6% 4 2 4 6% 3 5% 6% 6% 6% 52%	2160
	21st to end	Day	6% 5% 2 4 5% 2 3 4 5% 6% 59%	1958
October	1st to 10th	Day	4 6% 3 5% 5% 3 4 5% 6% 7% 52%	1800
	11th to 20th	Day	3 4 2 4 4 2 4 4 4 7% 63%	1800
	21st to end	Day	3 6% 2 5% 4 3 4 4 5% 7% 56%	1929
November	1st to 10th	Day	1 4 2 4 4 2 3 5% 6% 8% 63%	1673
	11th to 20th	Day	1 4 3 4 4 2 3 4 6% 11% 60%	1710
	21st to end	Day	3 2 6% 6% 3 4 4 5% 9% 57%	1547
December	1st to 10th	Day	3 3 7% 5% 3 5% 4 6% 10% 56%	1520
	11th to 20th	Day	1 3 2 5% 5% 3 4 6% 9% 10% 51%	1926
	21st to end	Day	4 4 9% 7% 3 5% 4 5% 9% 48%	2794
January	1st to 10th	Night	1 2 6% 8% 4 5% 5% 6% 9% 53%	4417
	11th to 20th	Night	1 1 3 5% 5% 5% 5% 6% 10% 59%	4366
	21st to end	Night	5% 4 7% 4 2 4 4 5% 8% 57%	4521
February	1st to 10th	Night	3 3 5% 6% 3 4 3 6% 10% 58%	2470
	11th to 20th	Night	3 2 5% 4 2 4 5% 6% 10% 60%	2287
	21st to end	Night	4 3 7% 6% 3 4 4 5% 8% 57%	1884
March	1st to 10th	Night	4 3 5% 4 2 4 4 7% 11% 57%	2271
	11th to 20th	Night	2 5% 3 5% 3 2 4 4 5% 9% 56%	2090
	21st to end	Night	2 6% 2 5% 4 2 4 4 7% 10% 54%	2088
April	1st to 10th	Night	1 6% 3 4 4 2 4 4 6% 8% 57%	1800
	11th to 20th	Night	4 7% 3 5% 5% 2 4 5% 5% 9% 52%	1777
	21st to end	Night	6% 9% 2 4 4 3 3 6% 5% 10% 49%	1800
May	1st to 10th	Night	6% 9% 3 5% 5% 3 5% 5% 6% 8% 45%	1642
	11th to 20th	Night	8% 11% 2 4 5% 3 4 4 4 8% 46%	1417
	21st to end	Night	5% 5% 2 4 6% 3 6% 5% 5% 8% 51%	1552
June	1st to 10th	Night	4 3 2 3 4 3 4 5% 6% 9% 58%	1440
	11th to 20th	Night	4 3 2 3 3 2 3 4 6% 8% 61%	1440
	21st to end	Night	3 3 1 3 3 3 4 7% 6% 8% 59%	1440
July	1st to 10th	Night	4 3 2 4 5% 4 6% 6% 7% 8% 51%	1440
	11th to 20th	Night	2 2 2 3 3 3 5% 4 7% 10% 60%	1440
	21st to end	Night	3 5% 3 4 6% 4 6% 5% 7% 9% 49%	1630
August	1st to 10th	Night	4 5% 2 4 5% 3 5% 7% 7% 9% 48%	1611
	11th to 20th	Night	4 4 1 4 4 3 5% 5% 6% 8% 57%	1731
	21st to end	Night	3 4 2 4 4 3 6% 5% 6% 8% 56%	1980
September	1st to 10th	Night	5% 5% 2 4 4 3 5% 4 4 7% 58%	1800
	11th to 20th	Night	5% 3 2 4 3 2 3 4 5% 7% 63%	1800
	21st to end	Night	5% 4 1 3 3 2 4 4 5% 6% 63%	1999
October	1st to 10th	Night	4 5% 2 3 4 2 4 4 5% 8% 59%	2160
	11th to 20th	Night	2 3 1 3 3 2 2 3 4 8% 69%	2160
	21st to end	Night	3 6% 2 4 4 2 4 3 5% 9% 57%	2407
November	1st to 10th	Night	1 3 2 3 2 2 3 4 5% 9% 66%	2405
	11th to 20th	Night	1 3 2 4 3 3 3 3 7% 10% 62%	2470
	21st to end	Night	1 4 3 5% 4 2 3 5% 5% 9% 59%	2631
December	1st to 10th	Night	3 1 5% 3 2 3 3 5% 10% 64%	2660
	11th to 20th	Night	1 4 3 6% 4 3 3 4 7% 12% 54%	3271
	21st to end	Night	5% 3 7% 6% 3 4 5% 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	33% 5% 17% 26% 18% 1	1905
	11th to 20th	Day	35% 6% 17% 24% 15% 3	2090
	21st to end	Day	38% 6% 16% 27% 11% 3	2313
April	1st to 10th	Day	34% 5% 16% 23% 16% 6%	2160
	11th to 20th	Day	43% 5% 16% 19% 15% 2	2134
	21st to end	Day	45% 5% 13% 25% 10% 1	2160
May	1st to 10th	Day	48% 5% 13% 20% 12% 1	2315
	11th to 20th	Day	48% 7% 13% 23% 9% 1	2482
	21st to end	Day	44% 8% 12% 19% 13% 4	2724
June	1st to 10th	Day	33% 9% 16% 21% 15% 6%	2520
	11th to 20th	Day	29% 7% 13% 17% 23% 11%	2520
	21st to end	Day	31% 7% 10% 21% 22% 10%	2520
July	1st to 10th	Day	36% 9% 11% 18% 19% 8%	2451
	11th to 20th	Day	33% 9% 12% 21% 16% 9%	2445
	21st to end	Day	42% 10% 14% 17% 11% 4	2535
August	1st to 10th	Day	44% 10% 13% 16% 12% 6%	2313
	11th to 20th	Day	38% 8% 8% 19% 19% 8%	2170
	21st to end	Day	39% 7% 11% 16% 21% 6%	2376
September	1st to 10th	Day	30% 6% 8% 19% 25% 12%	2160
	11th to 20th	Day	30% 7% 9% 20% 24% 10%	2160
	21st to end	Day	27% 4 7% 26% 29% 6%	1958
October	1st to 10th	Day	30% 6% 11% 24% 23% 6%	1800
	11th to 20th	Day	22% 5% 8% 32% 25% 7%	1800
	21st to end	Day	28% 3 13% 28% 19% 7%	1929
November	1st to 10th	Day	20% 5% 16% 26% 29% 4	1673
	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	22% 4 18% 32% 21% 3	2271
	11th to 20th	Night	25% 6% 16% 32% 17% 5%	2090
	21st to end	Night	26% 5% 21% 32% 13% 3	2088
April	1st to 10th	Night	27% 6% 18% 26% 17% 6%	1800
	11th to 20th	Night	31% 5% 18% 28% 16% 2	1777
	21st to end	Night	31% 6% 16% 29% 17% 1	1800
May	1st to 10th	Night	36% 8% 15% 25% 14% 2	1642
	11th to 20th	Night	38% 7% 17% 28% 11%	1418
	21st to end	Night	30% 6% 15% 27% 19% 3	1552
June	1st to 10th	Night	23% 8% 20% 28% 16% 6%	1440
	11th to 20th	Night	20% 6% 12% 22% 26% 13%	1440
	21st to end	Night	20% 6% 12% 27% 23% 12%	1440
July	1st to 10th	Night	29% 9% 13% 22% 19% 8%	1400
	11th to 20th	Night	20% 6% 17% 28% 19% 11%	1392
	21st to end	Night	29% 8% 20% 24% 14% 5%	1539
August	1st to 10th	Night	29% 10% 19% 22% 15% 5%	1602
	11th to 20th	Night	25% 6% 15% 21% 24% 9%	1731
	21st to end	Night	27% 6% 13% 24% 24% 7%	1980
September	1st to 10th	Night	26% 5% 11% 19% 27% 13%	1800
	11th to 20th	Night	21% 5% 12% 27% 23% 12%	1800
	21st to end	Night	22% 4 9% 32% 26% 7%	1999
October	1st to 10th	Night	24% 5% 11% 30% 23% 7%	2160
	11th to 20th	Night	17% 4 13% 32% 25% 9%	2160
	21st to end	Night	25% 5% 17% 27% 21% 6%	2407
November	1st to 10th	Night	17% 5% 16% 28% 27% 7%	2405
	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% 13% 4	460
	21st to end	Day	23% 38% 28% 9% 2	471
April	1st to 10th	Day	27% 35% 29% 6% 3	420
	11th to 20th	Day	34% 30% 24% 9% 2	412
	21st to end	Day	23% 29% 31% 12% 5% 1	420
May	1st to 10th	Day	23% 26% 30% 13% 6% 1	521
	11th to 20th	Day	22% 18% 31% 19% 9% 1	625
	21st to end	Day	17% 15% 30% 25% 10% 2	679
June	1st to 10th	Day	10% 15% 31% 24% 16% 4	630
	11th to 20th	Day	13% 20% 34% 22% 9% 3	630
	21st to end	Day	9% 12% 37% 25% 13% 4	630
July	1st to 10th	Day	8% 6% 28% 33% 19% 5%	621
	11th to 20th	Day	6% 9% 32% 31% 16% 6%	618
	21st to end	Day	9% 5% 25% 36% 18% 6%	626
August	1st to 10th	Day	14% 11% 31% 30% 12% 2	447
	11th to 20th	Day	13% 9% 32% 31% 11% 4	437
	21st to end	Day	12% 11% 28% 33% 11% 4	495
September	1st to 10th	Day	11% 16% 30% 26% 14% 2	450
	11th to 20th	Day	11% 19% 37% 19% 12% 2	450
	21st to end	Day	13% 20% 27% 22% 12% 5%	275
October	1st to 10th	Day	13% 19% 29% 25% 10% 4	270
	11th to 20th	Day	26% 29% 24% 14% 5% 1	270
	21st to end	Day	28% 28% 26% 14% 3 1	297
November	1st to 10th	Day	30% 32% 19% 11% 7% 1	270
	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% 33% 27% 17% 4 1	688
April	1st to 10th	Night	18% 27% 34% 17% 3	540
	11th to 20th	Night	17% 29% 26% 22% 6% 1	533
	21st to end	Night	17% 23% 28% 23% 8% 1	540
May	1st to 10th	Night	15% 19% 31% 24% 9% 2	540
	11th to 20th	Night	16% 10% 27% 32% 14% 2	531
	21st to end	Night	11% 10% 29% 29% 19% 2	584
June	1st to 10th	Night	7% 7% 27% 35% 21% 3	540
	11th to 20th	Night	6% 14% 31% 35% 12% 1	540
	21st to end	Night	6% 8% 24% 35% 24% 4	540
July	1st to 10th	Night	7% 2 16% 40% 30% 4	525
	11th to 20th	Night	3 4 22% 37% 28% 6%	522
	21st to end	Night	6% 2 12% 39% 36% 5%	591
August	1st to 10th	Night	9% 2 16% 42% 26% 5%	537
	11th to 20th	Night	6% 4 19% 45% 22% 4	534
	21st to end	Night	5% 6% 18% 37% 28% 7%	594
September	1st to 10th	Night	9% 5% 26% 35% 20% 6%	540
	11th to 20th	Night	8% 11% 26% 34% 16% 4	540
	21st to end	Night	10% 12% 28% 31% 15% 4	564
October	1st to 10th	Night	12% 23% 25% 27% 11% 3	720
	11th to 20th	Night	17% 27% 28% 21% 6% 2	720
	21st to end	Night	17% 31% 30% 14% 6% 2	823
November	1st to 10th	Night	18% 36% 26% 14% 6%	925
	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 2024-03-19 21:31:03. Version ac07

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