Navajo Peak
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Navajo Peak clear sky chart from 2005-11-06 to 2024-11-30.

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	6% 9% 3 6% 4 4 4 4 5% 6% 49%	105212
	Night	6% 10% 3 6% 3 3 4 3 5% 6% 51%	103130
Transparency	Day	19% 48% 5% 11% 13% 4	104967
	Night	19% 47% 5% 11% 13% 5%	102963
Seeing	Day	16% 21% 25% 23% 12% 3	15326
	Night	11% 9% 23% 34% 19% 3	25474

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 10% 4 13% 3 3 4 2 4 6% 48%	2732
	11th to 20th	Day	5% 12% 7% 13% 3 3 2 3 5% 6% 42%	2860
	21st to end	Day	5% 14% 6% 8% 3 3 4 3 4 5% 46%	3146
February	1st to 10th	Day	4 15% 6% 10% 3 3 2 2 3 5% 48%	1710
	11th to 20th	Day	6% 15% 5% 9% 3 3 3 3 4 6% 44%	1787
	21st to end	Day	5% 16% 7% 10% 2 3 3 3 4 5% 42%	1570
March	1st to 10th	Day	5% 17% 9% 7% 3 2 3 2 4 5% 44%	3343
	11th to 20th	Day	4 19% 5% 6% 4 5% 4 3 5% 6% 39%	3490
	21st to end	Day	5% 23% 7% 7% 3 3 3 3 3 5% 37%	3910
April	1st to 10th	Day	6% 12% 2 6% 4 3 3 3 4 8% 49%	2280
	11th to 20th	Day	5% 14% 2 5% 4 3 4 4 5% 7% 47%	2251
	21st to end	Day	8% 13% 2 4 3 3 4 4 5% 6% 47%	2280
May	1st to 10th	Day	7% 9% 3 5% 3 3 3 3 4 5% 54%	3821
	11th to 20th	Day	7% 10% 2 5% 5% 5% 5% 4 6% 7% 44%	4184
	21st to end	Day	5% 5% 1 4 3 3 3 3 5% 6% 61%	4825
June	1st to 10th	Day	4 3 1 3 3 4 4 4 6% 8% 58%	2660
	11th to 20th	Day	5% 3 1 3 2 2 4 3 5% 6% 67%	2660
	21st to end	Day	5% 4 2 5% 4 4 5% 4 6% 7% 55%	2660
July	1st to 10th	Day	6% 3 1 4 4 4 5% 5% 5% 6% 56%	4430
	11th to 20th	Day	3 3 2 6% 5% 6% 9% 8% 10% 11% 38%	4143
	21st to end	Day	6% 4 2 6% 6% 7% 8% 6% 8% 8% 39%	4454
August	1st to 10th	Day	10% 5% 3 8% 7% 7% 8% 6% 7% 8% 31%	4092
	11th to 20th	Day	5% 4 2 6% 5% 5% 6% 5% 7% 8% 48%	3764
	21st to end	Day	8% 6% 3 9% 7% 7% 7% 5% 7% 9% 33%	4180
September	1st to 10th	Day	11% 6% 1 6% 4 4 5% 4 5% 6% 49%	2280
	11th to 20th	Day	11% 5% 2 5% 4 3 5% 4 5% 5% 52%	2280
	21st to end	Day	12% 4 1 4 3 3 3 3 4 5% 59%	2034
October	1st to 10th	Day	8% 4 1 2 2 2 3 3 4 6% 65%	3170
	11th to 20th	Day	14% 8% 2 6% 4 3 3 3 4 5% 49%	3150
	21st to end	Day	7% 8% 3 3 2 2 1 2 2 5% 66%	3438
November	1st to 10th	Day	5% 7% 2 4 2 2 2 3 3 6% 65%	1889
	11th to 20th	Day	5% 7% 2 3 2 2 2 2 4 6% 67%	1800
	21st to end	Day	7% 10% 3 4 3 3 2 2 3 4 59%	1699
December	1st to 10th	Day	6% 11% 3 7% 2 1 2 2 3 7% 55%	1520
	11th to 20th	Day	6% 15% 3 7% 3 3 3 3 5% 6% 47%	1926
	21st to end	Day	4 12% 4 9% 2 2 3 3 4 6% 52%	2794
January	1st to 10th	Night	3 10% 4 14% 4 3 3 3 4 4 49%	4252
	11th to 20th	Night	2 14% 7% 11% 3 3 3 3 4 4 46%	4110
	21st to end	Night	4 14% 5% 8% 3 3 3 2 4 6% 48%	4521
February	1st to 10th	Night	4 14% 5% 6% 2 2 2 2 3 6% 54%	2470
	11th to 20th	Night	5% 15% 4 6% 3 2 3 2 3 4 53%	2279
	21st to end	Night	5% 18% 5% 7% 2 2 2 2 3 5% 48%	1884
March	1st to 10th	Night	4 21% 5% 5% 3 2 2 2 4 5% 46%	3523
	11th to 20th	Night	6% 21% 4 6% 3 3 4 3 5% 6% 41%	3490
	21st to end	Night	8% 21% 5% 7% 3 2 3 2 4 5% 41%	3738
April	1st to 10th	Night	8% 13% 2 4 3 3 3 3 5% 5% 51%	1900
	11th to 20th	Night	9% 13% 2 5% 3 3 3 3 4 5% 51%	1877
	21st to end	Night	10% 10% 1 3 3 3 3 3 4 5% 55%	1900
May	1st to 10th	Night	9% 10% 1 4 2 2 3 2 3 5% 58%	3146
	11th to 20th	Night	8% 7% 2 4 3 4 4 4 6% 7% 50%	2717
	21st to end	Night	8% 7% 1 3 3 2 3 3 4 5% 62%	2762
June	1st to 10th	Night	4 4 1 3 4 4 4 3 5% 6% 62%	1520
	11th to 20th	Night	4 4 1 3 2 2 3 3 4 6% 69%	1520
	21st to end	Night	6% 2 2 5% 4 4 4 4 8% 6% 55%	1520
July	1st to 10th	Night	5% 3 2 6% 5% 4 5% 4 6% 6% 54%	2540
	11th to 20th	Night	3 3 1 4 5% 5% 7% 6% 11% 15% 40%	2821
	21st to end	Night	5% 4 2 6% 6% 6% 6% 6% 9% 10% 40%	3109
August	1st to 10th	Night	9% 5% 3 7% 7% 7% 7% 7% 9% 11% 29%	2847
	11th to 20th	Night	5% 3 2 7% 6% 6% 6% 5% 8% 10% 41%	3075
	21st to end	Night	8% 6% 2 8% 6% 6% 7% 6% 8% 10% 33%	3487
September	1st to 10th	Night	7% 5% 2 5% 5% 5% 6% 4 6% 7% 47%	1900
	11th to 20th	Night	10% 4 1 4 4 3 4 3 4 5% 57%	1900
	21st to end	Night	10% 4 1 4 3 2 2 2 4 5% 62%	2139
October	1st to 10th	Night	7% 3 1 3 2 2 2 2 3 4 69%	3800
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 4 5% 55%	3778
	21st to end	Night	8% 7% 2 3 2 2 2 1 3 4 68%	4120
November	1st to 10th	Night	6% 7% 1 3 2 2 2 3 5% 5% 64%	2386
	11th to 20th	Night	5% 6% 1 3 2 2 2 2 4 5% 70%	2600
	21st to end	Night	8% 12% 2 4 2 2 2 2 3 4 58%	2695
December	1st to 10th	Night	7% 9% 3 7% 3 3 3 2 3 5% 57%	2660
	11th to 20th	Night	6% 12% 3 6% 3 3 4 3 6% 7% 45%	3271
	21st to end	Night	6% 13% 4 9% 4 2 2 2 3 5% 50%	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	26% 39% 8% 11% 12% 4	2733
	11th to 20th	Day	31% 40% 9% 15% 5% 1	2860
	21st to end	Day	24% 42% 4 14% 14% 2	3146
February	1st to 10th	Day	15% 64% 4 8% 5% 4	1710
	11th to 20th	Day	14% 64% 4 9% 8% 2	1796
	21st to end	Day	18% 64% 1 5% 9% 2	1570
March	1st to 10th	Day	23% 43% 4 13% 14% 3	3343
	11th to 20th	Day	26% 45% 4 16% 7% 1	3490
	21st to end	Day	30% 45% 6% 8% 11% 2	3910
April	1st to 10th	Day	12% 65% 4 9% 8% 1	2280
	11th to 20th	Day	13% 66% 3 8% 9% 2	2254
	21st to end	Day	17% 65% 3 7% 7% 1	2280
May	1st to 10th	Day	18% 43% 7% 10% 15% 7%	3821
	11th to 20th	Day	21% 44% 5% 13% 15% 3	4187
	21st to end	Day	11% 40% 4 12% 30% 3	4825
June	1st to 10th	Day	8% 67% 4 9% 9% 4	2660
	11th to 20th	Day	7% 65% 4 6% 11% 8%	2660
	21st to end	Day	9% 64% 4 9% 8% 6%	2660
July	1st to 10th	Day	14% 37% 4 6% 19% 20%	4361
	11th to 20th	Day	23% 40% 11% 17% 6% 2	4072
	21st to end	Day	21% 39% 10% 15% 11% 4	4314
August	1st to 10th	Day	35% 40% 12% 7% 4 2	4078
	11th to 20th	Day	20% 41% 10% 11% 14% 5%	3800
	21st to end	Day	33% 40% 7% 9% 10% 1	4179
September	1st to 10th	Day	13% 62% 4 9% 10% 3	2280
	11th to 20th	Day	14% 61% 2 8% 11% 5%	2280
	21st to end	Day	13% 60% 2 9% 13% 3	2034
October	1st to 10th	Day	11% 37% 1 12% 29% 10%	3170
	11th to 20th	Day	29% 37% 3 14% 13% 3	3150
	21st to end	Day	17% 36% 2 12% 28% 5%	3438
November	1st to 10th	Day	11% 55% 2 11% 16% 4	1889
	11th to 20th	Day	10% 56% 3 11% 16% 5%	1800
	21st to end	Day	16% 56% 2 10% 10% 7%	1699
December	1st to 10th	Day	14% 60% 4 9% 10% 4	1520
	11th to 20th	Day	17% 48% 3 13% 15% 4	1924
	21st to end	Day	17% 37% 5% 11% 20% 11%	2794
January	1st to 10th	Night	29% 38% 5% 11% 12% 5%	4252
	11th to 20th	Night	30% 41% 5% 15% 8% 2	4110
	21st to end	Night	24% 41% 4 15% 14% 2	4521
February	1st to 10th	Night	14% 64% 4 8% 6% 3	2470
	11th to 20th	Night	12% 64% 4 9% 9% 2	2279
	21st to end	Night	17% 64% 1 4 12% 2	1884
March	1st to 10th	Night	24% 43% 3 12% 16% 2	3523
	11th to 20th	Night	28% 44% 4 13% 9% 2	3490
	21st to end	Night	28% 45% 5% 11% 10% 1	3738
April	1st to 10th	Night	12% 65% 3 9% 10% 1	1900
	11th to 20th	Night	13% 65% 2 7% 10% 3	1877
	21st to end	Night	15% 65% 4 8% 8% 1	1900
May	1st to 10th	Night	17% 42% 5% 8% 23% 5%	3146
	11th to 20th	Night	16% 42% 5% 20% 12% 4	2718
	21st to end	Night	13% 40% 5% 9% 26% 6%	2762
June	1st to 10th	Night	8% 65% 4 8% 9% 5%	1520
	11th to 20th	Night	6% 65% 3 7% 11% 9%	1520
	21st to end	Night	9% 64% 5% 6% 8% 7%	1520
July	1st to 10th	Night	17% 36% 4 5% 15% 23%	2500
	11th to 20th	Night	17% 38% 14% 24% 5% 3	2769
	21st to end	Night	17% 39% 13% 19% 10% 2	3011
August	1st to 10th	Night	33% 41% 14% 5% 5% 1	2838
	11th to 20th	Night	22% 41% 14% 6% 13% 4	3105
	21st to end	Night	32% 39% 8% 10% 9% 1	3487
September	1st to 10th	Night	13% 61% 4 10% 10% 2	1900
	11th to 20th	Night	11% 60% 3 8% 12% 5%	1900
	21st to end	Night	12% 60% 2 9% 14% 3	2139
October	1st to 10th	Night	8% 37% 2 19% 26% 8%	3800
	11th to 20th	Night	26% 37% 2 16% 15% 4	3778
	21st to end	Night	17% 36% 1 13% 24% 9%	4120
November	1st to 10th	Night	11% 55% 2 10% 17% 4	2386
	11th to 20th	Night	10% 56% 2 12% 16% 4	2600
	21st to end	Night	17% 56% 2 9% 9% 6%	2695
December	1st to 10th	Night	14% 59% 4 10% 9% 3	2660
	11th to 20th	Night	17% 51% 4 9% 14% 6%	3272
	21st to end	Night	24% 37% 3 9% 15% 13%	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	19% 19% 33% 20% 7% 1	270
	11th to 20th	Day	21% 21% 29% 23% 6%	270
	21st to end	Day	12% 21% 35% 21% 10% 1	297
February	1st to 10th	Day	17% 28% 31% 17% 5% 1	270
	11th to 20th	Day	24% 28% 27% 16% 4	270
	21st to end	Day	31% 28% 26% 12% 3	225
March	1st to 10th	Day	26% 30% 21% 19% 3 1	393
	11th to 20th	Day	22% 29% 28% 14% 6% 1	460
	21st to end	Day	27% 36% 26% 7% 3	506
April	1st to 10th	Day	23% 35% 26% 10% 4 1	460
	11th to 20th	Day	27% 37% 24% 8% 4	452
	21st to end	Day	23% 33% 30% 10% 3	460
May	1st to 10th	Day	24% 31% 28% 12% 4	463
	11th to 20th	Day	18% 23% 27% 22% 9% 2	549
	21st to end	Day	16% 22% 27% 23% 11% 2	734
June	1st to 10th	Day	5% 15% 28% 30% 18% 5%	680
	11th to 20th	Day	9% 22% 29% 22% 15% 4	680
	21st to end	Day	7% 17% 27% 26% 17% 6%	680
July	1st to 10th	Day	8% 12% 16% 31% 26% 7%	671
	11th to 20th	Day	7% 6% 20% 35% 23% 9%	502
	21st to end	Day	9% 5% 15% 37% 28% 5%	531
August	1st to 10th	Day	11% 11% 18% 33% 19% 7%	487
	11th to 20th	Day	8% 12% 26% 33% 17% 5%	477
	21st to end	Day	10% 11% 21% 31% 22% 5%	539
September	1st to 10th	Day	11% 12% 26% 26% 18% 7%	490
	11th to 20th	Day	11% 17% 34% 22% 12% 4	490
	21st to end	Day	14% 17% 24% 27% 10% 8%	354
October	1st to 10th	Day	17% 21% 18% 24% 15% 5%	300
	11th to 20th	Day	19% 22% 24% 17% 14% 5%	300
	21st to end	Day	19% 24% 22% 22% 11% 2	330
November	1st to 10th	Day	20% 28% 21% 20% 10% 1	300
	11th to 20th	Day	13% 24% 26% 25% 11% 2	300
	21st to end	Day	20% 19% 27% 23% 10% 1	299
December	1st to 10th	Day	20% 20% 29% 23% 9% 1	270
	11th to 20th	Day	16% 26% 27% 22% 8% 1	270
	21st to end	Day	22% 24% 32% 20% 4	297
January	1st to 10th	Night	10% 10% 23% 38% 16% 3	850
	11th to 20th	Night	12% 9% 24% 37% 15% 2	760
	21st to end	Night	11% 9% 27% 36% 14% 3	836
February	1st to 10th	Night	12% 13% 29% 34% 11% 1	760
	11th to 20th	Night	13% 15% 30% 32% 10% 1	744
	21st to end	Night	18% 13% 33% 30% 5%	628
March	1st to 10th	Night	16% 15% 27% 30% 10% 1	760
	11th to 20th	Night	12% 13% 24% 37% 13% 1	760
	21st to end	Night	17% 14% 32% 29% 8% 1	784
April	1st to 10th	Night	17% 16% 33% 26% 7% 1	570
	11th to 20th	Night	16% 14% 30% 31% 8% 1	563
	21st to end	Night	14% 13% 32% 30% 9% 1	570
May	1st to 10th	Night	14% 10% 30% 32% 13% 1	570
	11th to 20th	Night	13% 7% 24% 37% 16% 2	561
	21st to end	Night	12% 12% 27% 31% 17% 1	617
June	1st to 10th	Night	4 6% 23% 46% 19% 2	570
	11th to 20th	Night	6% 9% 27% 39% 17% 2	570
	21st to end	Night	6% 4 20% 39% 28% 3	570
July	1st to 10th	Night	7% 4 14% 38% 34% 4	555
	11th to 20th	Night	4 2 7% 37% 41% 9%	552
	21st to end	Night	6% 3 8% 28% 46% 9%	624
August	1st to 10th	Night	8% 2 7% 25% 47% 10%	567
	11th to 20th	Night	7% 3 9% 35% 39% 7%	564
	21st to end	Night	7% 3 9% 34% 38% 8%	627
September	1st to 10th	Night	8% 3 10% 39% 33% 6%	570
	11th to 20th	Night	11% 3 14% 41% 25% 6%	570
	21st to end	Night	10% 7% 13% 34% 28% 8%	675
October	1st to 10th	Night	13% 7% 21% 34% 21% 4	760
	11th to 20th	Night	11% 6% 23% 37% 19% 4	760
	21st to end	Night	12% 9% 21% 33% 19% 5%	836
November	1st to 10th	Night	12% 8% 21% 38% 18% 4	826
	11th to 20th	Night	8% 9% 26% 39% 16% 3	1000
	21st to end	Night	15% 10% 23% 31% 17% 3	1000
December	1st to 10th	Night	13% 11% 26% 34% 14% 1	950
	11th to 20th	Night	14% 10% 26% 33% 16% 1	950
	21st to end	Night	14% 13% 27% 35% 9% 2	1045

Page generated at 2024-11-27 15:30:55. Version ac07

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