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Hole-in-the-Wall Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hole-in-the-Wall Campground clear sky chart from 2005-11-06 to 2024-05-13.

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 3 1 3 3 3 3 3 4 6% 69%	84000
	Night	3 3 1 3 2 3 3 3 4 6% 69%	85645
Transparency	Day	15% 3 3 15% 27% 36%	83727
	Night	15% 3 3 15% 28% 35%	85440
Seeing	Day	5% 11% 25% 34% 20% 5%	14706
	Night	4 8% 19% 34% 29% 6%	25037

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	3 4 2 4 3 3 3 2 4 6% 66%	2858
	11th to 20th	Day	4 3 2 5% 3 3 3 3 5% 7% 62%	2860
	21st to end	Day	8% 6% 2 5% 3 4 4 4 5% 5% 53%	3312
February	1st to 10th	Day	5% 4 1 3 3 3 3 3 5% 5% 65%	1900
	11th to 20th	Day	4 4 1 4 3 3 3 3 5% 5% 65%	1850
	21st to end	Day	5% 6% 1 4 3 3 3 3 3 6% 63%	1570
March	1st to 10th	Day	3 3 1 4 2 3 3 3 5% 8% 67%	3138
	11th to 20th	Day	5% 6% 2 4 3 3 4 3 5% 7% 57%	3476
	21st to end	Day	4 3 1 3 3 3 4 3 6% 8% 62%	3825
April	1st to 10th	Day	2 3 2 4 3 3 3 3 4 6% 67%	2251
	11th to 20th	Day	1 3 1 2 2 2 2 2 3 5% 76%	2249
	21st to end	Day	2 2 1 2 2 2 2 3 4 6% 75%	2383
May	1st to 10th	Day	1 1 1 2 2 2 2 2 5% 6% 75%	2470
	11th to 20th	Day	1 2 1 2 2 2 2 3 4 5% 78%	2329
	21st to end	Day	2 2 1 2 2 2 3 2 3 5% 76%	2530
June	1st to 10th	Day	1 2 1 2 2 1 2 2 3 5% 80%	2340
	11th to 20th	Day	1 1 1 2 1 3 2 3 4 82%	2340
	21st to end	Day	1 1 2 2 2 2 1 3 3 82%	2340
July	1st to 10th	Day	2 2 1 3 2 3 3 3 5% 5% 72%	2340
	11th to 20th	Day	3 3 1 3 2 2 3 3 6% 7% 67%	2340
	21st to end	Day	4 5% 2 4 4 5% 5% 4 6% 8% 54%	2545
August	1st to 10th	Day	2 3 1 3 3 3 3 2 3 6% 72%	2299
	11th to 20th	Day	2 2 1 3 3 3 3 3 5% 6% 70%	2122
	21st to end	Day	3 2 1 2 2 3 3 3 4 6% 71%	2376
September	1st to 10th	Day	2 2 1 2 2 2 3 3 4 6% 72%	2073
	11th to 20th	Day	1 1 1 1 2 1 2 2 3 4 82%	1980
	21st to end	Day	1 1 1 2 2 2 2 2 3 4 82%	1980
October	1st to 10th	Day	2 2 1 3 3 2 2 2 3 5% 75%	1980
	11th to 20th	Day	2 1 1 2 2 2 2 2 3 4 81%	1948
	21st to end	Day	1 1 1 2 1 2 2 2 3 5% 82%	1877
November	1st to 10th	Day	1 3 1 2 3 3 2 3 4 5% 74%	1674
	11th to 20th	Day	1 3 1 3 2 3 3 3 4 5% 72%	1710
	21st to end	Day	3 2 1 3 2 2 4 3 5% 7% 67%	1710
December	1st to 10th	Day	3 5% 2 6% 3 3 3 4 6% 7% 58%	1710
	11th to 20th	Day	5% 4 2 5% 4 3 3 3 7% 11% 52%	2169
	21st to end	Day	6% 5% 2 5% 3 4 5% 4 6% 7% 53%	3146
January	1st to 10th	Night	2 3 2 4 3 3 3 3 4 6% 66%	4097
	11th to 20th	Night	2 4 1 4 3 3 5% 4 6% 8% 60%	4110
	21st to end	Night	10% 5% 1 4 3 3 4 3 5% 6% 56%	4357
February	1st to 10th	Night	3 4 2 4 3 3 3 3 5% 5% 65%	2280
	11th to 20th	Night	3 4 2 3 2 3 3 4 5% 6% 66%	2218
	21st to end	Night	4 4 1 4 3 4 3 3 5% 6% 64%	1884
March	1st to 10th	Night	2 4 1 4 3 3 3 4 5% 6% 66%	3736
	11th to 20th	Night	4 5% 2 5% 4 4 4 4 6% 7% 56%	3503
	21st to end	Night	3 2 1 4 3 3 4 4 6% 7% 64%	3828
April	1st to 10th	Night	2 3 1 4 3 2 3 3 4 6% 68%	1924
	11th to 20th	Night	1 3 1 3 2 2 3 2 4 5% 74%	1879
	21st to end	Night	1 2 1 2 2 2 2 2 5% 6% 77%	1796
May	1st to 10th	Night	1 2 1 2 1 2 2 2 4 6% 76%	1710
	11th to 20th	Night	1 1 1 1 2 2 3 4 4 80%	1621
	21st to end	Night	1 1 1 1 2 2 2 3 5% 81%	1746
June	1st to 10th	Night	1 1 2 2 2 1 2 3 5% 81%	1620
	11th to 20th	Night	1 1 1 2 1 2 2 1 2 4 84%	1620
	21st to end	Night	1 2 1 2 2 2 2 3 2 84%	1620
July	1st to 10th	Night	1 1 2 2 2 2 3 3 5% 80%	1620
	11th to 20th	Night	3 2 1 3 2 3 4 3 5% 7% 66%	1620
	21st to end	Night	5% 3 2 4 3 4 4 4 6% 8% 57%	1773
August	1st to 10th	Night	2 2 1 3 2 2 3 2 4 6% 73%	1636
	11th to 20th	Night	1 1 1 2 2 2 2 3 4 7% 76%	1780
	21st to end	Night	2 2 3 2 2 2 2 5% 5% 75%	1980
September	1st to 10th	Night	2 2 1 3 2 2 3 2 4 5% 75%	1885
	11th to 20th	Night	1 1 1 2 2 1 2 1 3 3 85%	1980
	21st to end	Night	1 1 1 1 2 1 1 2 2 4 84%	1980
October	1st to 10th	Night	3 2 1 2 2 2 2 2 4 4 76%	1980
	11th to 20th	Night	1 1 2 1 1 2 1 2 4 84%	2011
	21st to end	Night	1 1 1 2 1 2 3 2 3 5% 79%	2474
November	1st to 10th	Night	1 3 1 3 2 2 2 2 3 4 77%	2405
	11th to 20th	Night	2 2 1 3 2 2 3 3 3 4 75%	2470
	21st to end	Night	3 4 1 3 2 3 4 3 4 6% 68%	2470
December	1st to 10th	Night	4 3 2 4 4 3 3 3 5% 7% 62%	2470
	11th to 20th	Night	5% 5% 2 5% 4 4 3 4 6% 9% 54%	3041
	21st to end	Night	4 5% 2 6% 4 4 5% 4 6% 7% 52%	4521

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	18% 3 3 23% 35% 18%	2859
	11th to 20th	Day	21% 2 5% 30% 26% 16%	2860
	21st to end	Day	29% 3 6% 17% 32% 13%	3312
February	1st to 10th	Day	20% 2 4 16% 27% 31%	1900
	11th to 20th	Day	19% 3 3 16% 29% 30%	1860
	21st to end	Day	22% 2 4 17% 32% 24%	1570
March	1st to 10th	Day	14% 4 3 19% 31% 28%	3138
	11th to 20th	Day	22% 5% 3 22% 30% 17%	3476
	21st to end	Day	15% 6% 2 23% 37% 16%	3825
April	1st to 10th	Day	17% 3 3 16% 30% 31%	2251
	11th to 20th	Day	12% 2 2 12% 32% 41%	2252
	21st to end	Day	11% 2 2 14% 35% 37%	2383
May	1st to 10th	Day	9% 3 2 14% 32% 40%	2470
	11th to 20th	Day	9% 2 2 10% 32% 46%	2332
	21st to end	Day	11% 2 1 10% 32% 43%	2530
June	1st to 10th	Day	8% 2 1 8% 23% 58%	2340
	11th to 20th	Day	5% 3 1 5% 15% 70%	2340
	21st to end	Day	9% 2 1 4 12% 72%	2340
July	1st to 10th	Day	13% 3 1 8% 16% 59%	2276
	11th to 20th	Day	15% 3 4 13% 24% 41%	2271
	21st to end	Day	22% 5% 6% 18% 19% 29%	2404
August	1st to 10th	Day	14% 4 3 9% 24% 48%	2284
	11th to 20th	Day	13% 5% 2 11% 27% 42%	2122
	21st to end	Day	14% 3 2 12% 26% 44%	2376
September	1st to 10th	Day	13% 4 3 10% 21% 49%	2073
	11th to 20th	Day	7% 2 1 7% 26% 58%	1980
	21st to end	Day	9% 2 1 9% 26% 54%	1980
October	1st to 10th	Day	14% 2 2 12% 25% 46%	1980
	11th to 20th	Day	9% 2 2 8% 26% 52%	1948
	21st to end	Day	7% 2 2 11% 29% 49%	1877
November	1st to 10th	Day	12% 3 1 13% 34% 37%	1674
	11th to 20th	Day	14% 2 3 13% 29% 39%	1710
	21st to end	Day	14% 3 4 17% 29% 33%	1710
December	1st to 10th	Day	22% 3 5% 18% 24% 28%	1710
	11th to 20th	Day	25% 4 8% 22% 25% 16%	2168
	21st to end	Day	27% 3 6% 23% 25% 14%	3146
January	1st to 10th	Night	17% 3 4 18% 37% 21%	4097
	11th to 20th	Night	18% 3 8% 26% 30% 16%	4110
	21st to end	Night	27% 4 6% 17% 31% 16%	4357
February	1st to 10th	Night	20% 3 5% 15% 26% 31%	2280
	11th to 20th	Night	17% 3 3 17% 30% 30%	2219
	21st to end	Night	19% 2 5% 17% 32% 26%	1884
March	1st to 10th	Night	17% 3 2 23% 32% 21%	3736
	11th to 20th	Night	23% 4 3 23% 28% 19%	3503
	21st to end	Night	14% 5% 3 20% 39% 18%	3828
April	1st to 10th	Night	16% 2 4 17% 32% 29%	1924
	11th to 20th	Night	12% 2 2 12% 34% 37%	1879
	21st to end	Night	9% 2 2 14% 34% 40%	1796
May	1st to 10th	Night	10% 3 3 13% 33% 39%	1710
	11th to 20th	Night	8% 2 2 13% 31% 45%	1622
	21st to end	Night	7% 1 2 13% 37% 40%	1746
June	1st to 10th	Night	7% 2 1 9% 24% 57%	1620
	11th to 20th	Night	7% 2 6% 18% 67%	1620
	21st to end	Night	8% 1 4 12% 74%	1620
July	1st to 10th	Night	8% 3 2 8% 15% 64%	1575
	11th to 20th	Night	15% 4 3 13% 24% 40%	1566
	21st to end	Night	21% 5% 6% 18% 21% 29%	1674
August	1st to 10th	Night	13% 3 3 11% 20% 49%	1627
	11th to 20th	Night	9% 4 4 12% 27% 45%	1780
	21st to end	Night	10% 3 1 12% 24% 49%	1980
September	1st to 10th	Night	13% 2 3 9% 25% 47%	1885
	11th to 20th	Night	6% 2 1 8% 24% 58%	1980
	21st to end	Night	7% 2 1 9% 23% 58%	1980
October	1st to 10th	Night	12% 2 2 12% 27% 46%	1980
	11th to 20th	Night	7% 2 2 8% 26% 55%	2011
	21st to end	Night	9% 2 2 10% 24% 53%	2474
November	1st to 10th	Night	11% 2 2 12% 36% 38%	2405
	11th to 20th	Night	12% 2 2 13% 29% 42%	2470
	21st to end	Night	16% 3 2 14% 28% 37%	2470
December	1st to 10th	Night	20% 3 4 16% 26% 31%	2470
	11th to 20th	Night	25% 3 5% 18% 27% 22%	3041
	21st to end	Night	27% 3 6% 22% 28% 13%	4521

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	11% 16% 26% 31% 14% 1	270
	11th to 20th	Day	10% 13% 27% 29% 18% 3	270
	21st to end	Day	10% 14% 30% 28% 15% 4	398
February	1st to 10th	Day	9% 17% 33% 27% 12% 2	460
	11th to 20th	Day	9% 18% 36% 27% 10% 1	455
	21st to end	Day	10% 22% 32% 26% 9% 1	382
March	1st to 10th	Day	9% 19% 35% 28% 9%	460
	11th to 20th	Day	10% 19% 32% 25% 12% 1	460
	21st to end	Day	6% 23% 39% 24% 7% 1	506
April	1st to 10th	Day	7% 17% 36% 23% 15% 2	460
	11th to 20th	Day	6% 21% 36% 25% 12% 2	452
	21st to end	Day	3 21% 27% 27% 16% 5%	460
May	1st to 10th	Day	4 17% 31% 30% 15% 3	463
	11th to 20th	Day	2 14% 28% 34% 17% 5%	457
	21st to end	Day	4 8% 31% 36% 16% 5%	485
June	1st to 10th	Day	3 7% 24% 38% 23% 5%	450
	11th to 20th	Day	1 6% 24% 38% 24% 7%	450
	21st to end	Day	2 6% 22% 43% 22% 6%	450
July	1st to 10th	Day	2 1 12% 45% 30% 10%	446
	11th to 20th	Day	3 1 10% 39% 35% 12%	444
	21st to end	Day	4 1 8% 45% 30% 11%	487
August	1st to 10th	Day	2 2 13% 44% 27% 12%	447
	11th to 20th	Day	2 1 10% 48% 27% 12%	437
	21st to end	Day	3 13% 41% 32% 11%	495
September	1st to 10th	Day	4 3 17% 39% 31% 6%	450
	11th to 20th	Day	1 3 22% 46% 24% 3	450
	21st to end	Day	2 8% 19% 40% 26% 5%	450
October	1st to 10th	Day	2 9% 29% 37% 21% 2	450
	11th to 20th	Day	3 9% 21% 40% 22% 5%	418
	21st to end	Day	3 10% 24% 30% 28% 5%	297
November	1st to 10th	Day	3 14% 23% 34% 23% 3	270
	11th to 20th	Day	4 11% 26% 33% 20% 6%	270
	21st to end	Day	6% 11% 24% 34% 20% 4	270
December	1st to 10th	Day	6% 8% 31% 36% 16% 3	270
	11th to 20th	Day	4 14% 25% 33% 21% 3	270
	21st to end	Day	11% 19% 27% 27% 13% 2	297
January	1st to 10th	Night	7% 9% 23% 34% 21% 7%	760
	11th to 20th	Night	6% 10% 25% 35% 21% 4	760
	21st to end	Night	9% 10% 26% 33% 18% 4	836
February	1st to 10th	Night	7% 10% 27% 31% 21% 4	760
	11th to 20th	Night	5% 10% 26% 36% 19% 4	744
	21st to end	Night	7% 12% 31% 31% 14% 4	628
March	1st to 10th	Night	4 14% 26% 37% 17% 1	760
	11th to 20th	Night	5% 14% 22% 29% 22% 8%	760
	21st to end	Night	4 14% 30% 32% 18% 3	836
April	1st to 10th	Night	4 14% 28% 32% 20% 3	760
	11th to 20th	Night	4 16% 27% 31% 19% 4	751
	21st to end	Night	2 13% 26% 31% 22% 6%	656
May	1st to 10th	Night	2 12% 24% 39% 19% 3	570
	11th to 20th	Night	1 11% 23% 30% 31% 4	540
	21st to end	Night	2 10% 22% 36% 26% 4	584
June	1st to 10th	Night	2 5% 14% 44% 33% 2	540
	11th to 20th	Night	1 4 18% 38% 36% 2	540
	21st to end	Night	2 3 14% 37% 40% 4	540
July	1st to 10th	Night	1 6% 32% 54% 6%	525
	11th to 20th	Night	4 4 33% 52% 7%	522
	21st to end	Night	4 1 5% 26% 59% 5%	591
August	1st to 10th	Night	3 1 6% 30% 55% 6%	562
	11th to 20th	Night	1 1 4 25% 58% 12%	712
	21st to end	Night	3 4 26% 51% 16%	792
September	1st to 10th	Night	3 2 5% 27% 50% 13%	720
	11th to 20th	Night	1 1 9% 39% 38% 12%	720
	21st to end	Night	2 3 14% 31% 36% 14%	720
October	1st to 10th	Night	3 5% 17% 42% 29% 5%	720
	11th to 20th	Night	2 6% 14% 39% 31% 8%	720
	21st to end	Night	3 7% 17% 33% 28% 12%	792
November	1st to 10th	Night	2 7% 17% 38% 29% 7%	740
	11th to 20th	Night	4 5% 18% 39% 26% 8%	760
	21st to end	Night	6% 8% 23% 33% 24% 6%	760
December	1st to 10th	Night	6% 8% 23% 38% 21% 5%	760
	11th to 20th	Night	9% 7% 21% 36% 23% 4	760
	21st to end	Night	8% 13% 24% 33% 16% 6%	836

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