Pinnacles Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pinnacles Campground clear sky chart from 2005-11-06 to 2024-11-02.

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	5% 4 1 3 2 2 3 2 4 5% 67%	100989
	Night	7% 5% 2 4 3 3 3 3 4 6% 62%	98223
Transparency	Day	19% 4 8% 16% 25% 28%	100745
	Night	23% 5% 9% 17% 23% 23%	98056
Seeing	Day	7% 9% 22% 30% 23% 9%	15463
	Night	7% 4 14% 35% 31% 8%	24911

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	11% 9% 3 6% 4 4 4 3 5% 7% 45%	2674
	11th to 20th	Day	13% 8% 3 7% 5% 4 5% 4 7% 6% 38%	2860
	21st to end	Day	16% 10% 3 8% 5% 4 5% 4 5% 7% 33%	3146
February	1st to 10th	Day	14% 8% 2 5% 3 3 3 4 5% 6% 49%	1710
	11th to 20th	Day	10% 7% 2 5% 4 3 4 4 5% 7% 48%	1842
	21st to end	Day	11% 9% 2 6% 4 3 4 4 5% 5% 47%	1570
March	1st to 10th	Day	11% 10% 3 8% 5% 4 6% 6% 8% 9% 31%	3284
	11th to 20th	Day	7% 5% 2 4 3 3 3 3 5% 8% 59%	3490
	21st to end	Day	10% 9% 3 7% 5% 5% 5% 4 7% 8% 38%	3962
April	1st to 10th	Day	9% 6% 2 4 4 3 4 4 6% 8% 51%	2280
	11th to 20th	Day	7% 5% 1 4 3 3 3 3 5% 6% 58%	2249
	21st to end	Day	5% 4 2 4 3 2 3 3 5% 7% 64%	2280
May	1st to 10th	Day	4 3 1 3 2 1 2 2 3 5% 73%	3800
	11th to 20th	Day	2 1 2 2 1 2 2 3 5% 80%	4106
	21st to end	Day	2 2 1 3 2 2 2 2 3 5% 78%	4813
June	1st to 10th	Day	2 2 1 2 3 3 3 2 4 8% 71%	2660
	11th to 20th	Day	1 1 1 1 1 1 1 2 5% 84%	2660
	21st to end	Day	1 1 1 1 1 2 1 2 3 87%	2660
July	1st to 10th	Day	1 1 1 2 2 92%	4420
	11th to 20th	Day	1 1 1 1 2 1 1 2 4 84%	4175
	21st to end	Day	1 1 1 1 1 1 2 3 89%	4455
August	1st to 10th	Day	1 1 2 1 1 2 2 3 4 82%	4040
	11th to 20th	Day	1 1 1 2 2 92%	3724
	21st to end	Day	1 1 1 1 1 1 2 2 90%	4180
September	1st to 10th	Day	1 1 1 1 1 1 1 1 2 89%	2280
	11th to 20th	Day	2 2 1 1 2 2 2 3 6% 80%	2280
	21st to end	Day	2 1 2 1 2 2 1 3 4 82%	2057
October	1st to 10th	Day	2 3 1 3 3 2 2 3 4 5% 73%	1900
	11th to 20th	Day	3 2 1 3 3 2 2 2 4 6% 72%	1900
	21st to end	Day	4 3 1 3 2 3 3 2 5% 5% 69%	2090
November	1st to 10th	Day	5% 4 2 4 4 4 3 3 5% 7% 58%	1799
	11th to 20th	Day	5% 4 1 4 2 3 4 3 5% 8% 59%	1710
	21st to end	Day	8% 5% 2 4 3 3 3 3 5% 8% 57%	1691
December	1st to 10th	Day	10% 6% 2 4 4 4 5% 3 7% 8% 47%	1520
	11th to 20th	Day	25% 9% 2 4 4 4 3 3 6% 7% 32%	1928
	21st to end	Day	15% 10% 3 6% 4 4 4 3 5% 7% 38%	2794
January	1st to 10th	Night	11% 7% 3 7% 4 3 4 3 6% 6% 47%	4272
	11th to 20th	Night	14% 9% 3 6% 4 4 4 4 6% 7% 38%	4110
	21st to end	Night	17% 12% 3 6% 4 4 4 4 4 7% 36%	4521
February	1st to 10th	Night	14% 6% 2 4 3 3 3 4 4 5% 51%	2470
	11th to 20th	Night	9% 6% 2 5% 4 3 4 3 5% 9% 51%	2223
	21st to end	Night	9% 8% 2 6% 3 3 4 3 5% 6% 50%	1884
March	1st to 10th	Night	15% 12% 3 8% 5% 5% 4 4 5% 6% 34%	3586
	11th to 20th	Night	6% 5% 2 5% 3 3 3 3 4 7% 58%	3490
	21st to end	Night	12% 13% 3 6% 4 4 4 3 5% 7% 38%	3689
April	1st to 10th	Night	8% 6% 1 5% 4 3 4 4 5% 7% 54%	1900
	11th to 20th	Night	5% 5% 1 4 4 2 4 3 5% 6% 60%	1879
	21st to end	Night	3 4 1 3 3 3 3 3 6% 9% 62%	1900
May	1st to 10th	Night	1 2 1 3 2 2 2 2 4 6% 74%	3180
	11th to 20th	Night	1 2 2 2 1 2 2 4 6% 78%	2786
	21st to end	Night	1 2 1 3 2 1 2 2 3 5% 78%	2762
June	1st to 10th	Night	2 3 1 2 2 3 3 3 5% 7% 71%	1520
	11th to 20th	Night	1 1 1 2 1 2 2 1 3 4 82%	1520
	21st to end	Night	1 1 1 1 1 1 3 3 88%	1520
July	1st to 10th	Night	1 1 1 2 3 92%	2540
	11th to 20th	Night	1 1 2 1 2 2 2 3 85%	2788
	21st to end	Night	1 1 1 1 1 1 3 4 87%	3109
August	1st to 10th	Night	1 1 1 1 1 2 2 2 3 4 83%	2901
	11th to 20th	Night	1 1 1 1 1 2 2 92%	3126
	21st to end	Night	1 1 1 1 1 1 1 2 3 88%	3498
September	1st to 10th	Night	2 2 1 2 1 2 3 87%	1900
	11th to 20th	Night	1 1 1 2 2 2 2 1 3 6% 79%	1900
	21st to end	Night	1 2 2 1 1 1 2 2 5% 83%	2116
October	1st to 10th	Night	4 3 1 2 2 2 3 2 3 5% 73%	2280
	11th to 20th	Night	3 3 1 2 3 2 3 3 4 7% 70%	2280
	21st to end	Night	4 3 1 2 1 2 2 3 4 6% 72%	2508
November	1st to 10th	Night	4 4 2 4 4 2 3 3 4 7% 62%	2313
	11th to 20th	Night	6% 3 2 4 3 3 3 3 5% 9% 58%	2470
	21st to end	Night	6% 5% 2 4 3 3 3 3 5% 7% 58%	2484
December	1st to 10th	Night	11% 6% 2 5% 3 3 4 3 5% 7% 52%	2660
	11th to 20th	Night	21% 10% 2 6% 4 4 4 3 6% 6% 34%	3276
	21st to end	Night	15% 9% 3 7% 4 4 5% 4 6% 7% 36%	4862

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	37% 9% 12% 26% 13% 3	2674
	11th to 20th	Day	42% 9% 11% 17% 12% 9%	2860
	21st to end	Day	47% 6% 10% 17% 14% 6%	3146
February	1st to 10th	Day	35% 5% 8% 18% 20% 14%	1710
	11th to 20th	Day	33% 7% 10% 19% 22% 10%	1852
	21st to end	Day	37% 6% 8% 20% 21% 7%	1570
March	1st to 10th	Day	42% 11% 14% 14% 15% 4	3284
	11th to 20th	Day	24% 6% 12% 26% 21% 12%	3490
	21st to end	Day	38% 8% 14% 22% 14% 4	3962
April	1st to 10th	Day	30% 6% 11% 24% 21% 8%	2280
	11th to 20th	Day	24% 6% 11% 27% 23% 9%	2252
	21st to end	Day	20% 5% 10% 31% 28% 7%	2280
May	1st to 10th	Day	14% 3 8% 26% 34% 16%	3800
	11th to 20th	Day	9% 3 9% 20% 41% 18%	4109
	21st to end	Day	11% 4 9% 25% 41% 11%	4814
June	1st to 10th	Day	12% 4 12% 23% 31% 18%	2660
	11th to 20th	Day	6% 2 6% 17% 38% 32%	2660
	21st to end	Day	7% 2 3 8% 28% 53%	2660
July	1st to 10th	Day	2 1 2 4 12% 79%	4351
	11th to 20th	Day	7% 2 3 5% 16% 67%	4103
	21st to end	Day	4 1 2 6% 24% 63%	4315
August	1st to 10th	Day	8% 1 3 8% 28% 52%	4025
	11th to 20th	Day	2 2 5% 35% 56%	3760
	21st to end	Day	4 1 3 8% 31% 53%	4179
September	1st to 10th	Day	5% 1 3 7% 27% 56%	2280
	11th to 20th	Day	9% 2 6% 16% 39% 28%	2280
	21st to end	Day	8% 2 4 15% 41% 29%	2057
October	1st to 10th	Day	14% 4 6% 17% 24% 35%	1900
	11th to 20th	Day	14% 3 6% 21% 27% 28%	1900
	21st to end	Day	18% 3 6% 17% 32% 25%	2090
November	1st to 10th	Day	23% 4 12% 17% 25% 20%	1799
	11th to 20th	Day	22% 7% 10% 19% 27% 14%	1710
	21st to end	Day	24% 6% 9% 17% 28% 15%	1691
December	1st to 10th	Day	31% 8% 10% 17% 20% 15%	1520
	11th to 20th	Day	50% 6% 9% 14% 15% 7%	1928
	21st to end	Day	43% 9% 12% 19% 12% 5%	2794
January	1st to 10th	Night	36% 10% 13% 23% 14% 3	4272
	11th to 20th	Night	42% 11% 13% 16% 11% 8%	4110
	21st to end	Night	46% 8% 11% 15% 13% 6%	4521
February	1st to 10th	Night	34% 5% 9% 18% 21% 13%	2470
	11th to 20th	Night	28% 6% 12% 21% 25% 8%	2224
	21st to end	Night	32% 6% 11% 26% 18% 7%	1884
March	1st to 10th	Night	48% 11% 10% 15% 12% 4	3586
	11th to 20th	Night	25% 7% 12% 26% 19% 11%	3490
	21st to end	Night	42% 9% 14% 20% 12% 3	3689
April	1st to 10th	Night	27% 8% 15% 23% 20% 7%	1900
	11th to 20th	Night	21% 7% 14% 28% 23% 7%	1879
	21st to end	Night	17% 6% 13% 30% 27% 7%	1900
May	1st to 10th	Night	11% 5% 12% 28% 29% 15%	3180
	11th to 20th	Night	9% 4 8% 20% 42% 17%	2786
	21st to end	Night	9% 4 10% 27% 44% 5%	2762
June	1st to 10th	Night	12% 5% 11% 22% 33% 17%	1520
	11th to 20th	Night	7% 3 6% 18% 36% 31%	1520
	21st to end	Night	3 1 4 10% 31% 51%	1520
July	1st to 10th	Night	2 2 5% 13% 79%	2500
	11th to 20th	Night	5% 2 3 4 17% 68%	2737
	21st to end	Night	4 1 3 7% 23% 62%	3011
August	1st to 10th	Night	8% 1 2 6% 22% 61%	2892
	11th to 20th	Night	3 1 2 5% 27% 63%	3156
	21st to end	Night	5% 1 4 7% 28% 55%	3498
September	1st to 10th	Night	7% 2 3 6% 25% 58%	1900
	11th to 20th	Night	9% 2 6% 18% 32% 33%	1900
	21st to end	Night	8% 1 5% 16% 40% 30%	2116
October	1st to 10th	Night	15% 4 6% 17% 25% 33%	2280
	11th to 20th	Night	14% 4 8% 16% 30% 27%	2280
	21st to end	Night	14% 4 5% 20% 31% 26%	2508
November	1st to 10th	Night	21% 6% 9% 19% 26% 20%	2313
	11th to 20th	Night	22% 6% 12% 18% 28% 14%	2470
	21st to end	Night	24% 5% 10% 16% 28% 16%	2484
December	1st to 10th	Night	32% 6% 9% 17% 22% 14%	2660
	11th to 20th	Night	48% 6% 10% 15% 14% 6%	3276
	21st to end	Night	44% 9% 16% 16% 10% 5%	4862

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	26% 12% 28% 18% 13% 3	263
	11th to 20th	Day	13% 9% 24% 27% 20% 7%	370
	21st to end	Day	13% 11% 22% 27% 21% 5%	407
February	1st to 10th	Day	17% 16% 21% 21% 16% 8%	370
	11th to 20th	Day	17% 13% 24% 26% 17% 3	452
	21st to end	Day	12% 15% 28% 30% 13% 2	382
March	1st to 10th	Day	20% 13% 25% 28% 12% 2	460
	11th to 20th	Day	17% 14% 25% 25% 14% 4	460
	21st to end	Day	15% 15% 33% 26% 10% 2	506
April	1st to 10th	Day	13% 16% 27% 25% 15% 4	460
	11th to 20th	Day	11% 16% 29% 25% 15% 5%	452
	21st to end	Day	6% 17% 30% 27% 13% 7%	460
May	1st to 10th	Day	9% 12% 33% 26% 15% 5%	463
	11th to 20th	Day	5% 11% 32% 30% 15% 8%	488
	21st to end	Day	6% 10% 25% 31% 20% 9%	529
June	1st to 10th	Day	3 7% 28% 31% 21% 10%	490
	11th to 20th	Day	3 8% 24% 37% 20% 9%	490
	21st to end	Day	1 4 21% 33% 27% 13%	490
July	1st to 10th	Day	1 1 16% 36% 31% 15%	486
	11th to 20th	Day	1 10% 36% 34% 19%	484
	21st to end	Day	1 1 10% 37% 32% 19%	531
August	1st to 10th	Day	2 2 16% 37% 29% 15%	487
	11th to 20th	Day	1 1 18% 33% 31% 17%	477
	21st to end	Day	1 1 11% 33% 35% 20%	539
September	1st to 10th	Day	1 4 13% 33% 32% 17%	490
	11th to 20th	Day	3 6% 21% 33% 27% 10%	490
	21st to end	Day	3 4 14% 32% 36% 11%	490
October	1st to 10th	Day	3 6% 21% 32% 28% 10%	490
	11th to 20th	Day	4 8% 18% 30% 28% 12%	490
	21st to end	Day	6% 8% 22% 26% 27% 10%	539
November	1st to 10th	Day	6% 9% 21% 25% 30% 9%	389
	11th to 20th	Day	3 9% 19% 28% 31% 10%	270
	21st to end	Day	10% 4 21% 34% 26% 5%	261
December	1st to 10th	Day	14% 8% 22% 26% 23% 7%	180
	11th to 20th	Day	13% 12% 21% 25% 21% 8%	180
	21st to end	Day	18% 15% 19% 23% 19% 6%	198
January	1st to 10th	Night	16% 5% 15% 34% 22% 8%	760
	11th to 20th	Night	11% 4 15% 38% 26% 7%	760
	21st to end	Night	14% 4 16% 36% 24% 6%	836
February	1st to 10th	Night	16% 5% 15% 34% 23% 7%	760
	11th to 20th	Night	10% 8% 18% 33% 24% 6%	744
	21st to end	Night	12% 6% 19% 41% 19% 3	628
March	1st to 10th	Night	13% 8% 19% 36% 20% 4	760
	11th to 20th	Night	11% 7% 19% 35% 23% 6%	760
	21st to end	Night	11% 9% 20% 35% 21% 4	836
April	1st to 10th	Night	10% 7% 22% 37% 21% 3	760
	11th to 20th	Night	6% 11% 21% 34% 22% 6%	751
	21st to end	Night	3 8% 26% 31% 26% 7%	760
May	1st to 10th	Night	3 7% 23% 37% 23% 7%	760
	11th to 20th	Night	3 3 17% 39% 32% 7%	540
	21st to end	Night	3 4 17% 36% 34% 6%	411
June	1st to 10th	Night	2 3 15% 43% 32% 5%	380
	11th to 20th	Night	1 2 16% 42% 34% 5%	380
	21st to end	Night	1 9% 41% 42% 8%	380
July	1st to 10th	Night	1 7% 33% 51% 8%	370
	11th to 20th	Night	1 3 23% 56% 17%	509
	21st to end	Night	4 20% 58% 17%	624
August	1st to 10th	Night	1 5% 30% 50% 14%	594
	11th to 20th	Night	1 8% 34% 45% 12%	752
	21st to end	Night	1 1 6% 25% 55% 12%	836
September	1st to 10th	Night	1 1 7% 34% 45% 13%	760
	11th to 20th	Night	1 1 11% 36% 39% 11%	760
	21st to end	Night	2 1 11% 33% 41% 12%	760
October	1st to 10th	Night	4 3 12% 36% 35% 10%	760
	11th to 20th	Night	5% 3 10% 36% 34% 12%	760
	21st to end	Night	5% 3 12% 33% 31% 17%	836
November	1st to 10th	Night	5% 5% 12% 37% 31% 11%	748
	11th to 20th	Night	7% 3 13% 37% 32% 8%	760
	21st to end	Night	7% 3 17% 37% 28% 8%	760
December	1st to 10th	Night	12% 4 15% 40% 23% 7%	760
	11th to 20th	Night	15% 5% 16% 39% 23% 3	760
	21st to end	Night	15% 8% 20% 33% 20% 4	836

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