Mahogany Flat Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mahogany Flat Campground clear sky chart from 2005-11-06 to 2024-11-25.

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	2 2 1 2 2 2 3 2 4 5% 75%	105289
	Night	2 2 1 3 2 2 3 2 4 5% 74%	102950
Transparency	Day	13% 3 3 14% 27% 40%	105041
	Night	14% 3 4 15% 27% 38%	102787
Seeing	Day	8% 16% 36% 29% 9% 2	15356
	Night	5% 10% 26% 34% 21% 4	25110

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 2 1 3 3 3 4 4 5% 7% 66%	2539
	11th to 20th	Day	2 3 1 4 3 5% 4 4 6% 9% 60%	2547
	21st to end	Day	6% 4 2 5% 3 4 5% 3 6% 8% 55%	3438
February	1st to 10th	Day	4 4 1 4 3 3 2 3 4 5% 67%	1900
	11th to 20th	Day	3 3 1 3 3 2 4 4 5% 8% 64%	1850
	21st to end	Day	4 4 2 3 3 3 3 3 4 7% 64%	1570
March	1st to 10th	Day	1 2 1 4 2 3 4 4 6% 7% 64%	3138
	11th to 20th	Day	3 4 2 4 3 3 4 3 6% 7% 61%	3321
	21st to end	Day	2 4 1 3 3 3 4 4 6% 8% 62%	4058
April	1st to 10th	Day	2 2 2 3 3 3 4 3 5% 6% 67%	2280
	11th to 20th	Day	1 3 1 2 3 3 3 2 3 6% 74%	2249
	21st to end	Day	1 2 3 3 2 2 3 4 5% 74%	2302
May	1st to 10th	Day	1 2 1 1 1 1 2 2 4 4 80%	4110
	11th to 20th	Day	1 1 1 2 1 2 2 2 3 4 81%	4071
	21st to end	Day	1 2 1 2 2 2 2 2 2 4 82%	4477
June	1st to 10th	Day	1 1 1 2 3 2 2 3 4 5% 77%	2532
	11th to 20th	Day	1 1 1 2 2 2 2 4 85%	2660
	21st to end	Day	1 1 1 1 2 1 2 2 2 85%	2660
July	1st to 10th	Day	1 1 1 1 1 1 1 2 2 87%	4420
	11th to 20th	Day	2 1 1 2 2 2 3 2 4 4 77%	4402
	21st to end	Day	2 1 1 1 2 2 3 2 3 5% 79%	4454
August	1st to 10th	Day	3 2 1 1 1 2 2 3 3 81%	3855
	11th to 20th	Day	1 1 1 1 1 1 2 2 90%	3724
	21st to end	Day	1 1 1 1 1 1 1 2 2 89%	4180
September	1st to 10th	Day	1 1 1 2 2 1 3 2 2 4 82%	2280
	11th to 20th	Day	1 1 1 1 1 1 2 3 89%	2096
	21st to end	Day	1 1 1 1 1 1 2 2 3 87%	2090
October	1st to 10th	Day	1 1 1 2 1 1 2 2 3 4 83%	3490
	11th to 20th	Day	1 1 1 2 1 2 2 2 2 3 83%	3353
	21st to end	Day	1 1 1 1 2 3 3 5% 5% 78%	3173
November	1st to 10th	Day	1 1 1 1 2 2 2 3 4 6% 77%	1764
	11th to 20th	Day	1 2 2 2 2 3 2 4 6% 77%	1800
	21st to end	Day	3 2 1 2 3 2 3 3 5% 6% 72%	1746
December	1st to 10th	Day	3 3 2 3 2 3 5% 3 4 7% 65%	1710
	11th to 20th	Day	4 5% 2 5% 4 4 5% 4 7% 9% 52%	2169
	21st to end	Day	6% 5% 2 5% 4 4 4 4 7% 7% 52%	2881
January	1st to 10th	Night	2 4 1 5% 3 3 3 3 5% 6% 66%	4406
	11th to 20th	Night	1 3 1 4 2 4 5% 3 5% 8% 62%	4407
	21st to end	Night	5% 5% 2 5% 3 4 4 3 5% 7% 57%	4233
February	1st to 10th	Night	3 4 2 4 3 2 3 3 5% 6% 63%	2280
	11th to 20th	Night	2 2 2 4 3 3 4 3 4 7% 66%	2218
	21st to end	Night	3 4 2 3 3 2 2 3 5% 6% 66%	1884
March	1st to 10th	Night	1 3 2 4 4 3 4 3 5% 6% 66%	3736
	11th to 20th	Night	6% 4 2 4 2 4 4 4 6% 7% 58%	3658
	21st to end	Night	1 4 1 3 3 3 3 3 5% 7% 66%	3592
April	1st to 10th	Night	2 2 1 3 3 3 3 3 5% 6% 70%	1900
	11th to 20th	Night	1 2 1 4 3 3 2 2 5% 5% 72%	1879
	21st to end	Night	1 2 1 2 3 2 2 3 4 5% 75%	1876
May	1st to 10th	Night	1 1 1 1 2 1 2 1 3 3 83%	2860
	11th to 20th	Night	1 1 1 1 1 1 2 2 3 4 83%	2834
	21st to end	Night	1 1 1 1 1 2 2 3 3 85%	3110
June	1st to 10th	Night	1 1 1 2 2 2 1 2 4 6% 79%	1643
	11th to 20th	Night	1 1 1 1 2 2 1 2 2 3 84%	1520
	21st to end	Night	1 1 2 1 1 1 1 3 4 84%	1520
July	1st to 10th	Night	1 1 1 1 1 1 1 1 2 90%	2540
	11th to 20th	Night	1 2 1 2 2 2 2 2 3 4 79%	2557
	21st to end	Night	1 2 1 2 1 2 2 2 4 4 79%	3109
August	1st to 10th	Night	2 2 1 2 1 2 2 2 3 4 80%	3088
	11th to 20th	Night	1 1 1 1 1 1 2 3 88%	3126
	21st to end	Night	1 1 1 1 1 1 1 2 91%	3498
September	1st to 10th	Night	2 1 1 2 2 2 2 1 3 3 81%	1900
	11th to 20th	Night	1 1 1 2 2 1 3 3 85%	2083
	21st to end	Night	1 1 1 1 1 2 2 3 87%	2090
October	1st to 10th	Night	1 1 1 1 1 1 1 2 3 88%	3490
	11th to 20th	Night	1 1 1 1 1 2 2 3 4 85%	3581
	21st to end	Night	1 1 2 1 1 2 2 5% 5% 79%	4385
November	1st to 10th	Night	1 1 1 3 2 2 2 2 5% 6% 77%	2535
	11th to 20th	Night	1 2 1 2 2 2 3 3 4 6% 74%	2600
	21st to end	Night	3 2 1 3 2 2 2 2 4 6% 72%	2528
December	1st to 10th	Night	3 4 1 4 3 3 3 3 5% 6% 65%	2470
	11th to 20th	Night	3 5% 2 4 3 3 4 4 6% 11% 55%	3041
	21st to end	Night	4 3 2 4 5% 5% 5% 5% 7% 8% 52%	4773

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	17% 4 6% 35% 32% 8%	2539
	11th to 20th	Day	22% 3 12% 31% 22% 9%	2547
	21st to end	Day	28% 4 8% 29% 24% 7%	3438
February	1st to 10th	Day	20% 3 6% 19% 35% 18%	1900
	11th to 20th	Day	19% 3 4 20% 34% 20%	1860
	21st to end	Day	21% 4 6% 21% 31% 17%	1570
March	1st to 10th	Day	17% 4 4 25% 31% 18%	3138
	11th to 20th	Day	21% 4 7% 25% 28% 15%	3321
	21st to end	Day	18% 5% 5% 25% 32% 15%	4058
April	1st to 10th	Day	19% 3 3 20% 32% 23%	2280
	11th to 20th	Day	14% 2 3 15% 36% 29%	2252
	21st to end	Day	13% 3 3 18% 38% 25%	2302
May	1st to 10th	Day	9% 3 2 12% 40% 35%	4110
	11th to 20th	Day	9% 2 1 8% 38% 42%	4074
	21st to end	Day	9% 3 1 9% 37% 41%	4477
June	1st to 10th	Day	10% 3 2 11% 25% 49%	2532
	11th to 20th	Day	6% 2 1 7% 21% 62%	2660
	21st to end	Day	8% 2 1 3 14% 73%	2660
July	1st to 10th	Day	7% 1 1 3 7% 82%	4351
	11th to 20th	Day	11% 2 2 6% 14% 65%	4327
	21st to end	Day	10% 2 2 11% 20% 54%	4314
August	1st to 10th	Day	10% 2 2 6% 24% 56%	3841
	11th to 20th	Day	4 2 3 16% 75%	3760
	21st to end	Day	5% 1 3 16% 74%	4179
September	1st to 10th	Day	9% 2 1 5% 20% 63%	2280
	11th to 20th	Day	5% 1 1 7% 26% 59%	2096
	21st to end	Day	6% 2 1 8% 31% 53%	2090
October	1st to 10th	Day	8% 2 1 7% 23% 59%	3490
	11th to 20th	Day	9% 2 1 8% 35% 45%	3353
	21st to end	Day	8% 1 2 12% 38% 38%	3173
November	1st to 10th	Day	10% 2 3 15% 44% 26%	1764
	11th to 20th	Day	11% 2 4 21% 36% 26%	1800
	21st to end	Day	15% 3 4 20% 32% 27%	1746
December	1st to 10th	Day	20% 4 8% 24% 27% 17%	1710
	11th to 20th	Day	27% 5% 11% 20% 27% 10%	2168
	21st to end	Day	31% 4 9% 25% 23% 8%	2881
January	1st to 10th	Night	20% 3 5% 29% 37% 7%	4406
	11th to 20th	Night	20% 3 11% 32% 24% 9%	4407
	21st to end	Night	27% 3 11% 24% 26% 8%	4233
February	1st to 10th	Night	22% 3 7% 19% 29% 20%	2280
	11th to 20th	Night	20% 3 3 21% 29% 24%	2219
	21st to end	Night	19% 3 4 21% 35% 18%	1884
March	1st to 10th	Night	16% 7% 4 22% 33% 19%	3736
	11th to 20th	Night	24% 5% 5% 22% 29% 15%	3658
	21st to end	Night	16% 5% 3 22% 39% 14%	3592
April	1st to 10th	Night	16% 3 4 19% 35% 23%	1900
	11th to 20th	Night	15% 3 2 15% 36% 28%	1879
	21st to end	Night	12% 3 2 15% 40% 29%	1876
May	1st to 10th	Night	8% 2 2 12% 38% 38%	2860
	11th to 20th	Night	7% 3 1 10% 34% 45%	2835
	21st to end	Night	6% 2 1 9% 35% 47%	3110
June	1st to 10th	Night	10% 1 1 10% 23% 54%	1643
	11th to 20th	Night	9% 1 8% 18% 63%	1520
	21st to end	Night	7% 1 3 13% 75%	1520
July	1st to 10th	Night	5% 1 2 6% 86%	2500
	11th to 20th	Night	9% 3 2 6% 12% 68%	2509
	21st to end	Night	9% 3 2 10% 21% 55%	3011
August	1st to 10th	Night	10% 3 1 7% 20% 59%	3079
	11th to 20th	Night	5% 1 1 3 12% 78%	3156
	21st to end	Night	5% 1 3 12% 79%	3498
September	1st to 10th	Night	11% 2 1 4 18% 64%	1900
	11th to 20th	Night	7% 2 1 7% 22% 62%	2083
	21st to end	Night	5% 2 6% 28% 59%	2090
October	1st to 10th	Night	6% 1 1 6% 17% 69%	3490
	11th to 20th	Night	7% 2 1 7% 29% 55%	3581
	21st to end	Night	8% 2 2 10% 34% 44%	4385
November	1st to 10th	Night	10% 2 3 16% 40% 29%	2535
	11th to 20th	Night	13% 3 4 17% 32% 31%	2600
	21st to end	Night	16% 2 3 17% 32% 30%	2528
December	1st to 10th	Night	21% 4 7% 19% 29% 20%	2470
	11th to 20th	Night	24% 5% 10% 23% 27% 11%	3041
	21st to end	Night	28% 4 10% 25% 25% 9%	4773

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	12% 22% 44% 18% 3 1	180
	11th to 20th	Day	13% 21% 39% 21% 6% 1	184
	21st to end	Day	11% 17% 32% 29% 9% 1	472
February	1st to 10th	Day	13% 21% 36% 20% 8% 1	460
	11th to 20th	Day	15% 25% 36% 21% 3	455
	21st to end	Day	16% 27% 34% 18% 5%	382
March	1st to 10th	Day	14% 29% 32% 19% 5%	460
	11th to 20th	Day	18% 26% 31% 19% 6%	460
	21st to end	Day	17% 28% 36% 16% 3	506
April	1st to 10th	Day	12% 24% 36% 20% 6% 2	460
	11th to 20th	Day	14% 27% 34% 16% 8% 1	452
	21st to end	Day	9% 23% 38% 22% 5% 3	460
May	1st to 10th	Day	13% 22% 38% 19% 5% 2	463
	11th to 20th	Day	7% 17% 41% 27% 5% 3	488
	21st to end	Day	7% 16% 37% 33% 6% 2	529
June	1st to 10th	Day	5% 10% 39% 33% 11% 2	490
	11th to 20th	Day	4 16% 38% 30% 10% 2	490
	21st to end	Day	3 13% 36% 37% 9% 2	490
July	1st to 10th	Day	3 4 38% 41% 10% 4	486
	11th to 20th	Day	3 2 33% 45% 12% 5%	484
	21st to end	Day	4 4 31% 43% 13% 5%	531
August	1st to 10th	Day	4 10% 38% 33% 10% 5%	487
	11th to 20th	Day	4 7% 34% 39% 9% 6%	477
	21st to end	Day	4 6% 37% 37% 12% 4	539
September	1st to 10th	Day	1 7% 37% 39% 12% 4	490
	11th to 20th	Day	6% 12% 38% 33% 9% 2	490
	21st to end	Day	5% 15% 33% 35% 10% 2	490
October	1st to 10th	Day	6% 15% 35% 33% 8% 1	490
	11th to 20th	Day	6% 13% 34% 32% 12% 1	490
	21st to end	Day	7% 13% 34% 31% 12% 2	378
November	1st to 10th	Day	7% 17% 31% 30% 14% 1	300
	11th to 20th	Day	8% 15% 38% 25% 11% 3	300
	21st to end	Day	7% 16% 37% 29% 12%	282
December	1st to 10th	Day	8% 18% 38% 24% 11%	270
	11th to 20th	Day	8% 15% 36% 28% 11% 1	270
	21st to end	Day	15% 22% 36% 18% 7% 2	221
January	1st to 10th	Night	10% 9% 24% 31% 21% 4	760
	11th to 20th	Night	6% 8% 32% 35% 17% 3	760
	21st to end	Night	9% 13% 26% 31% 17% 3	836
February	1st to 10th	Night	7% 14% 24% 36% 17% 3	760
	11th to 20th	Night	8% 12% 30% 33% 15% 3	744
	21st to end	Night	10% 16% 32% 28% 14% 1	628
March	1st to 10th	Night	7% 15% 33% 28% 14% 3	760
	11th to 20th	Night	9% 15% 26% 26% 19% 4	760
	21st to end	Night	8% 16% 34% 27% 13% 2	836
April	1st to 10th	Night	7% 14% 29% 32% 14% 3	760
	11th to 20th	Night	5% 17% 33% 28% 13% 3	751
	21st to end	Night	5% 13% 31% 30% 17% 4	736
May	1st to 10th	Night	4 13% 36% 32% 13% 2	570
	11th to 20th	Night	4 13% 22% 39% 20% 2	561
	21st to end	Night	3 12% 28% 35% 20% 2	617
June	1st to 10th	Night	3 7% 28% 39% 20% 3	503
	11th to 20th	Night	3 7% 29% 39% 18% 3	380
	21st to end	Night	2 4 27% 37% 26% 4	380
July	1st to 10th	Night	2 3 24% 43% 24% 5%	370
	11th to 20th	Night	3 1 22% 43% 28% 2	372
	21st to end	Night	4 2 22% 42% 29% 1	624
August	1st to 10th	Night	3 3 28% 43% 21% 3	704
	11th to 20th	Night	2 4 18% 45% 29% 2	752
	21st to end	Night	4 2 19% 41% 30% 4	836
September	1st to 10th	Night	3 4 19% 36% 32% 5%	760
	11th to 20th	Night	2 8% 22% 38% 24% 6%	760
	21st to end	Night	1 9% 21% 34% 28% 8%	760
October	1st to 10th	Night	2 9% 25% 37% 21% 5%	760
	11th to 20th	Night	5% 7% 20% 34% 26% 8%	760
	21st to end	Night	4 12% 20% 31% 24% 9%	836
November	1st to 10th	Night	4 9% 22% 36% 22% 6%	780
	11th to 20th	Night	5% 9% 23% 34% 25% 5%	800
	21st to end	Night	7% 12% 25% 30% 23% 4	778
December	1st to 10th	Night	6% 10% 26% 33% 21% 4	760
	11th to 20th	Night	8% 13% 24% 34% 18% 3	760
	21st to end	Night	8% 14% 24% 33% 18% 3	836

Page generated at 2024-11-22 05:02:23. Version ac07

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