Hondo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hondo clear sky chart from 2005-11-06 to 2024-12-24.

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	13% 6% 2 5% 4 4 4 3 5% 7% 48%	101397
	Night	13% 5% 2 4 3 3 3 3 5% 7% 52%	98822
Transparency	Day	34% 6% 10% 21% 19% 10%	105267
	Night	31% 6% 12% 21% 19% 13%	103079
Seeing	Day	14% 4 17% 30% 26% 9%	14867
	Night	15% 4 22% 40% 18% 1	24889

By Month

Percentage Cloud Cover SE (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	14% 5% 2 4 2 2 3 2 4 5% 58%	2847
	11th to 20th	Day	16% 5% 2 3 2 2 3 2 4 5% 57%	2918
	21st to end	Day	17% 8% 2 4 3 3 3 3 5% 8% 44%	3487
February	1st to 10th	Day	18% 8% 2 5% 4 3 3 3 4 4 46%	1900
	11th to 20th	Day	19% 6% 2 6% 3 2 4 2 4 5% 46%	1849
	21st to end	Day	16% 6% 2 4 3 2 3 3 3 7% 50%	1570
March	1st to 10th	Day	17% 8% 3 5% 3 3 3 3 4 5% 45%	3302
	11th to 20th	Day	22% 9% 3 8% 4 4 3 3 5% 4 35%	3480
	21st to end	Day	16% 6% 2 5% 3 3 3 3 5% 7% 47%	3814
April	1st to 10th	Day	15% 7% 2 5% 3 4 4 3 5% 7% 46%	2090
	11th to 20th	Day	18% 6% 2 5% 4 3 4 4 5% 5% 45%	2163
	21st to end	Day	16% 8% 2 6% 4 4 3 3 4 6% 45%	2327
May	1st to 10th	Day	22% 7% 2 6% 4 4 3 4 5% 7% 35%	4082
	11th to 20th	Day	14% 6% 2 6% 5% 4 4 4 6% 7% 43%	4082
	21st to end	Day	11% 6% 2 6% 4 5% 5% 4 6% 9% 42%	4477
June	1st to 10th	Day	7% 4 2 3 5% 5% 5% 4 7% 9% 49%	2470
	11th to 20th	Day	6% 5% 2 5% 5% 5% 5% 5% 6% 8% 48%	2470
	21st to end	Day	8% 5% 2 7% 6% 6% 5% 4 6% 9% 41%	2470
July	1st to 10th	Day	8% 5% 2 6% 4 4 4 4 5% 8% 50%	4120
	11th to 20th	Day	6% 4 2 5% 4 5% 5% 4 6% 11% 48%	4120
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 5% 7% 11% 41%	4465
August	1st to 10th	Day	2 2 1 2 3 3 3 3 5% 8% 70%	3803
	11th to 20th	Day	4 2 1 3 3 3 4 4 7% 10% 60%	3726
	21st to end	Day	5% 3 1 5% 4 5% 5% 4 7% 11% 50%	4094
September	1st to 10th	Day	11% 7% 3 7% 5% 4 4 5% 7% 7% 41%	2090
	11th to 20th	Day	11% 5% 2 7% 5% 5% 5% 5% 6% 8% 41%	2090
	21st to end	Day	8% 6% 2 5% 4 5% 5% 4 6% 8% 48%	2090
October	1st to 10th	Day	7% 4 1 5% 4 3 4 4 5% 7% 55%	2090
	11th to 20th	Day	14% 4 2 4 4 4 4 3 3 6% 51%	2046
	21st to end	Day	12% 5% 2 4 2 3 2 2 4 5% 59%	2090
November	1st to 10th	Day	18% 8% 2 6% 3 2 3 3 4 6% 45%	1958
	11th to 20th	Day	15% 6% 2 5% 3 3 3 4 4 6% 49%	1804
	21st to end	Day	18% 6% 2 5% 4 4 3 2 4 5% 47%	1800
December	1st to 10th	Day	20% 6% 3 5% 3 3 3 2 5% 6% 45%	1800
	11th to 20th	Day	17% 8% 3 5% 4 3 3 3 4 5% 45%	2251
	21st to end	Day	15% 6% 2 4 3 3 3 3 3 4 55%	3162
January	1st to 10th	Night	17% 5% 1 4 2 2 2 2 4 6% 56%	4108
	11th to 20th	Night	13% 4 1 2 2 1 2 1 3 4 67%	4079
	21st to end	Night	22% 6% 2 5% 3 2 3 2 4 6% 45%	4180
February	1st to 10th	Night	16% 5% 1 5% 3 2 3 3 3 6% 53%	2280
	11th to 20th	Night	19% 6% 2 3 3 2 3 2 4 4 51%	2218
	21st to end	Night	16% 5% 2 4 4 2 3 3 5% 7% 49%	1884
March	1st to 10th	Night	17% 9% 2 5% 4 3 3 3 4 6% 44%	3553
	11th to 20th	Night	19% 8% 3 7% 4 4 4 2 4 5% 39%	3480
	21st to end	Night	16% 6% 1 4 3 3 4 4 5% 6% 48%	3817
April	1st to 10th	Night	12% 6% 1 5% 4 3 4 3 5% 7% 50%	2090
	11th to 20th	Night	16% 6% 2 5% 4 3 3 3 5% 5% 48%	1962
	21st to end	Night	17% 6% 2 5% 3 3 3 3 3 6% 48%	1852
May	1st to 10th	Night	21% 6% 2 4 3 3 3 3 4 6% 43%	2823
	11th to 20th	Night	13% 6% 2 4 3 4 4 3 5% 7% 51%	2823
	21st to end	Night	12% 5% 2 6% 4 3 4 3 5% 7% 49%	3090
June	1st to 10th	Night	5% 2 2 3 2 3 4 3 5% 10% 62%	1710
	11th to 20th	Night	5% 3 1 4 3 3 4 3 7% 8% 58%	1710
	21st to end	Night	7% 4 2 4 3 4 3 5% 6% 9% 53%	1710
July	1st to 10th	Night	5% 4 2 4 3 3 3 4 6% 9% 56%	2850
	11th to 20th	Night	5% 4 2 6% 3 4 4 4 7% 10% 52%	2850
	21st to end	Night	9% 5% 2 5% 4 4 4 5% 7% 9% 47%	3098
August	1st to 10th	Night	1 2 2 2 2 3 2 5% 7% 73%	3117
	11th to 20th	Night	3 2 1 2 3 3 4 3 6% 11% 62%	3113
	21st to end	Night	4 4 2 4 3 3 4 4 6% 11% 56%	3567
September	1st to 10th	Night	9% 6% 2 6% 4 5% 4 3 6% 8% 48%	2090
	11th to 20th	Night	10% 5% 2 6% 5% 4 4 4 6% 8% 45%	2090
	21st to end	Night	7% 5% 2 5% 4 4 4 4 6% 8% 51%	2090
October	1st to 10th	Night	6% 3 1 4 3 2 3 3 4 7% 62%	2090
	11th to 20th	Night	12% 5% 2 3 3 3 4 3 4 7% 55%	2114
	21st to end	Night	14% 4 1 3 2 2 2 2 3 4 64%	2508
November	1st to 10th	Night	14% 6% 2 5% 3 3 2 2 4 5% 54%	2340
	11th to 20th	Night	11% 4 2 4 4 3 4 3 5% 6% 55%	2592
	21st to end	Night	18% 5% 1 4 4 3 4 3 4 6% 49%	2600
December	1st to 10th	Night	19% 5% 2 5% 3 2 2 3 4 6% 50%	2600
	11th to 20th	Night	18% 7% 2 5% 3 2 3 2 3 5% 48%	3166
	21st to end	Night	17% 5% 2 3 2 2 3 3 4 7% 52%	4578

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	30% 3 4 17% 27% 19%	2848
	11th to 20th	Day	32% 2 6% 15% 25% 20%	2918
	21st to end	Day	39% 4 6% 14% 27% 10%	3487
February	1st to 10th	Day	42% 4 5% 12% 19% 17%	1900
	11th to 20th	Day	41% 3 6% 16% 19% 14%	1859
	21st to end	Day	36% 4 7% 17% 20% 16%	1570
March	1st to 10th	Day	42% 4 7% 15% 19% 12%	3302
	11th to 20th	Day	52% 5% 7% 10% 16% 11%	3480
	21st to end	Day	36% 5% 10% 17% 16% 16%	3814
April	1st to 10th	Day	39% 6% 9% 16% 18% 14%	2090
	11th to 20th	Day	40% 6% 7% 18% 17% 13%	2163
	21st to end	Day	42% 5% 5% 18% 17% 12%	2327
May	1st to 10th	Day	47% 7% 10% 16% 12% 7%	4120
	11th to 20th	Day	36% 8% 11% 21% 17% 8%	4086
	21st to end	Day	34% 10% 11% 31% 12% 1	4489
June	1st to 10th	Day	27% 10% 15% 27% 19% 3	2470
	11th to 20th	Day	30% 8% 12% 26% 18% 5%	2470
	21st to end	Day	36% 8% 13% 25% 14% 3	2470
July	1st to 10th	Day	31% 6% 15% 38% 8% 1	4056
	11th to 20th	Day	29% 7% 18% 28% 15% 1	4051
	21st to end	Day	33% 8% 18% 30% 11%	4325
August	1st to 10th	Day	13% 5% 12% 43% 26% 1	3789
	11th to 20th	Day	18% 7% 22% 40% 12% 2	3762
	21st to end	Day	27% 8% 19% 24% 19% 2	4093
September	1st to 10th	Day	40% 8% 12% 18% 16% 7%	2090
	11th to 20th	Day	38% 8% 11% 19% 18% 5%	2090
	21st to end	Day	32% 8% 10% 21% 17% 12%	2090
October	1st to 10th	Day	18% 3 7% 12% 24% 36%	3480
	11th to 20th	Day	28% 5% 8% 17% 20% 23%	3377
	21st to end	Day	26% 4 6% 15% 34% 14%	3428
November	1st to 10th	Day	40% 4 9% 19% 15% 12%	1958
	11th to 20th	Day	35% 4 8% 16% 19% 17%	1804
	21st to end	Day	41% 4 6% 16% 20% 13%	1800
December	1st to 10th	Day	42% 4 7% 18% 19% 10%	1800
	11th to 20th	Day	41% 6% 7% 10% 20% 16%	2249
	21st to end	Day	34% 4 6% 16% 28% 13%	3162
January	1st to 10th	Night	30% 3 5% 15% 23% 23%	4108
	11th to 20th	Night	25% 2 4 18% 26% 25%	4079
	21st to end	Night	42% 3 5% 13% 26% 12%	4180
February	1st to 10th	Night	35% 4 7% 14% 20% 20%	2280
	11th to 20th	Night	38% 3 6% 16% 20% 17%	2218
	21st to end	Night	35% 5% 8% 15% 19% 17%	1884
March	1st to 10th	Night	41% 5% 9% 16% 18% 11%	3553
	11th to 20th	Night	46% 8% 8% 13% 12% 12%	3480
	21st to end	Night	34% 7% 12% 16% 18% 13%	3817
April	1st to 10th	Night	33% 5% 11% 19% 17% 15%	2090
	11th to 20th	Night	37% 5% 11% 14% 16% 17%	1962
	21st to end	Night	39% 6% 10% 18% 16% 12%	1852
May	1st to 10th	Night	40% 7% 11% 18% 14% 10%	2850
	11th to 20th	Night	33% 8% 11% 22% 18% 9%	2824
	21st to end	Night	33% 9% 13% 30% 13% 2	3099
June	1st to 10th	Night	18% 8% 19% 31% 22% 3	1710
	11th to 20th	Night	22% 6% 14% 31% 24% 5%	1710
	21st to end	Night	26% 9% 19% 28% 15% 3	1710
July	1st to 10th	Night	23% 7% 25% 37% 7% 1	2805
	11th to 20th	Night	27% 8% 20% 28% 16% 1	2796
	21st to end	Night	31% 9% 23% 27% 10% 1	2999
August	1st to 10th	Night	11% 6% 16% 44% 23% 1	3107
	11th to 20th	Night	17% 7% 30% 37% 8% 1	3143
	21st to end	Night	23% 11% 23% 24% 17% 2	3567
September	1st to 10th	Night	34% 7% 15% 21% 15% 7%	2090
	11th to 20th	Night	35% 10% 14% 21% 16% 5%	2090
	21st to end	Night	28% 7% 13% 23% 16% 12%	2090
October	1st to 10th	Night	16% 4 8% 17% 21% 36%	3480
	11th to 20th	Night	22% 4 10% 15% 26% 22%	3509
	21st to end	Night	23% 3 7% 18% 32% 16%	4120
November	1st to 10th	Night	33% 4 8% 19% 21% 14%	2340
	11th to 20th	Night	30% 5% 9% 18% 21% 17%	2592
	21st to end	Night	36% 5% 8% 17% 19% 15%	2600
December	1st to 10th	Night	36% 4 8% 18% 20% 13%	2600
	11th to 20th	Night	40% 4 6% 14% 17% 20%	3167
	21st to end	Night	33% 5% 6% 14% 27% 16%	4578

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	20% 7% 27% 33% 12% 1	270
	11th to 20th	Day	22% 7% 24% 31% 14% 2	270
	21st to end	Day	18% 5% 30% 35% 11% 1	297
February	1st to 10th	Day	29% 7% 26% 23% 14% 1	270
	11th to 20th	Day	23% 8% 35% 23% 10% 1	270
	21st to end	Day	26% 6% 38% 23% 7%	225
March	1st to 10th	Day	23% 7% 36% 29% 5%	270
	11th to 20th	Day	18% 7% 38% 29% 8% 1	270
	21st to end	Day	17% 9% 39% 28% 6%	297
April	1st to 10th	Day	21% 7% 35% 29% 9%	270
	11th to 20th	Day	17% 9% 36% 28% 10% 1	361
	21st to end	Day	18% 7% 34% 35% 6% 1	507
May	1st to 10th	Day	22% 4 29% 34% 12%	653
	11th to 20th	Day	19% 3 26% 36% 14% 2	675
	21st to end	Day	19% 4 23% 34% 19% 1	734
June	1st to 10th	Day	8% 1 13% 40% 33% 6%	680
	11th to 20th	Day	7% 2 11% 44% 31% 5%	680
	21st to end	Day	9% 1 7% 34% 37% 11%	680
July	1st to 10th	Day	12% 2 4 28% 41% 14%	671
	11th to 20th	Day	5% 2 3 25% 51% 14%	668
	21st to end	Day	5% 1 4 25% 46% 18%	739
August	1st to 10th	Day	2 1 2 30% 44% 23%	505
	11th to 20th	Day	5% 1 3 27% 44% 20%	477
	21st to end	Day	6% 2 4 22% 39% 27%	492
September	1st to 10th	Day	11% 1 2 23% 32% 30%	300
	11th to 20th	Day	7% 1 3 15% 44% 30%	300
	21st to end	Day	8% 1 4 23% 43% 22%	300
October	1st to 10th	Day	7% 7% 26% 45% 15%	300
	11th to 20th	Day	12% 2 8% 37% 32% 9%	300
	21st to end	Day	16% 6% 18% 28% 24% 8%	330
November	1st to 10th	Day	23% 2 17% 30% 20% 8%	300
	11th to 20th	Day	22% 4 17% 31% 19% 6%	300
	21st to end	Day	23% 7% 29% 27% 12% 3	300
December	1st to 10th	Day	24% 6% 18% 31% 18% 3	300
	11th to 20th	Day	24% 9% 18% 32% 16% 1	300
	21st to end	Day	21% 4 25% 34% 16% 2	306
January	1st to 10th	Night	20% 4 24% 40% 12% 1	950
	11th to 20th	Night	20% 6% 23% 41% 8%	922
	21st to end	Night	22% 5% 25% 38% 11%	836
February	1st to 10th	Night	21% 7% 26% 37% 9%	760
	11th to 20th	Night	24% 6% 30% 33% 7%	744
	21st to end	Night	21% 5% 37% 33% 3	628
March	1st to 10th	Night	21% 7% 33% 33% 6%	657
	11th to 20th	Night	20% 7% 33% 35% 5%	570
	21st to end	Night	17% 7% 40% 32% 4	627
April	1st to 10th	Night	14% 7% 40% 36% 4	570
	11th to 20th	Night	19% 7% 42% 29% 3	563
	21st to end	Night	21% 6% 39% 28% 6%	570
May	1st to 10th	Night	15% 6% 42% 32% 5%	570
	11th to 20th	Night	16% 4 32% 39% 8%	561
	21st to end	Night	15% 2 34% 38% 11%	617
June	1st to 10th	Night	7% 1 21% 51% 19% 1	570
	11th to 20th	Night	6% 1 24% 52% 15% 1	570
	21st to end	Night	8% 1 14% 49% 27% 1	570
July	1st to 10th	Night	10% 1 6% 50% 30% 2	555
	11th to 20th	Night	4 9% 50% 34% 3	552
	21st to end	Night	4 2 7% 46% 39% 2	624
August	1st to 10th	Night	2 6% 46% 43% 2	567
	11th to 20th	Night	5% 1 5% 49% 38% 2	564
	21st to end	Night	6% 2 5% 37% 44% 4	627
September	1st to 10th	Night	10% 2 4 45% 34% 6%	570
	11th to 20th	Night	11% 2 6% 40% 38% 4	570
	21st to end	Night	8% 1 8% 43% 36% 4	570
October	1st to 10th	Night	8% 1 8% 50% 31% 2	570
	11th to 20th	Night	14% 1 17% 42% 23% 2	594
	21st to end	Night	15% 3 19% 34% 25% 2	836
November	1st to 10th	Night	15% 3 17% 39% 24% 2	780
	11th to 20th	Night	13% 3 19% 44% 20% 2	992
	21st to end	Night	19% 4 21% 39% 16% 1	1000
December	1st to 10th	Night	22% 4 19% 39% 14% 2	1000
	11th to 20th	Night	26% 5% 19% 38% 11% 1	1000
	21st to end	Night	19% 5% 21% 43% 12% 1	1063

Page generated at 2024-12-21 03:13:47. Version ac07

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