Escondido Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Escondido Ranch clear sky chart from 2005-11-06 to 2024-11-03.

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	10% 5% 2 5% 4 4 4 4 6% 8% 49%	100909
	Night	10% 5% 2 4 3 3 4 3 5% 8% 54%	98180
Transparency	Day	32% 7% 12% 23% 18% 8%	100721
	Night	29% 7% 14% 23% 17% 10%	98040
Seeing	Day	10% 5% 21% 34% 24% 7%	14550
	Night	11% 5% 30% 40% 12% 1	24499

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 5% 3 3 3 2 3 4 55%	2847
	11th to 20th	Day	13% 4 2 4 2 2 2 2 4 6% 58%	2954
	21st to end	Day	18% 7% 2 6% 4 4 5% 4 5% 7% 38%	3487
February	1st to 10th	Day	15% 7% 3 6% 4 3 3 3 4 5% 45%	1900
	11th to 20th	Day	15% 7% 3 4 4 3 3 2 4 6% 50%	1849
	21st to end	Day	13% 6% 2 4 3 3 3 4 4 6% 52%	1570
March	1st to 10th	Day	14% 7% 2 8% 5% 4 5% 4 7% 8% 38%	3366
	11th to 20th	Day	22% 8% 3 7% 4 4 4 3 4 5% 36%	3480
	21st to end	Day	9% 4 2 5% 3 4 3 3 5% 7% 55%	3814
April	1st to 10th	Day	10% 6% 3 5% 3 3 4 4 5% 8% 49%	2090
	11th to 20th	Day	12% 7% 2 8% 4 4 4 3 5% 6% 45%	2071
	21st to end	Day	10% 6% 2 6% 4 4 4 4 5% 6% 49%	2323
May	1st to 10th	Day	11% 6% 3 8% 5% 5% 4 4 5% 8% 40%	4082
	11th to 20th	Day	9% 6% 2 6% 5% 4 4 4 6% 7% 47%	4082
	21st to end	Day	4 4 2 5% 4 5% 5% 4 6% 9% 52%	4477
June	1st to 10th	Day	4 2 1 4 4 4 4 5% 7% 9% 56%	2470
	11th to 20th	Day	3 3 1 4 4 5% 5% 4 7% 9% 54%	2470
	21st to end	Day	6% 4 1 5% 6% 6% 6% 5% 7% 10% 43%	2470
July	1st to 10th	Day	6% 5% 2 5% 5% 4 5% 4 7% 8% 50%	4120
	11th to 20th	Day	5% 6% 3 7% 6% 6% 5% 4 7% 10% 41%	4120
	21st to end	Day	6% 5% 2 6% 6% 5% 5% 5% 7% 10% 44%	4450
August	1st to 10th	Day	1 1 2 3 2 3 3 4 8% 73%	3785
	11th to 20th	Day	2 2 1 3 3 3 5% 5% 8% 11% 56%	3726
	21st to end	Day	4 3 2 5% 4 6% 6% 5% 8% 12% 44%	4021
September	1st to 10th	Day	10% 6% 3 7% 5% 6% 7% 4 6% 7% 40%	2090
	11th to 20th	Day	10% 5% 2 7% 5% 5% 6% 4 8% 8% 40%	2090
	21st to end	Day	7% 5% 2 5% 4 4 6% 4 6% 9% 50%	2090
October	1st to 10th	Day	6% 4 2 4 4 4 4 4 6% 6% 56%	2090
	11th to 20th	Day	10% 4 1 5% 3 4 4 3 5% 6% 54%	2038
	21st to end	Day	9% 3 2 4 3 3 3 3 3 5% 62%	2090
November	1st to 10th	Day	12% 6% 3 6% 4 4 3 4 5% 6% 48%	1878
	11th to 20th	Day	13% 6% 2 6% 3 3 3 3 5% 6% 49%	1803
	21st to end	Day	15% 7% 2 6% 4 4 3 3 4 5% 46%	1710
December	1st to 10th	Day	17% 7% 3 5% 3 4 3 2 4 7% 46%	1710
	11th to 20th	Day	18% 8% 2 6% 4 3 4 3 4 6% 43%	2161
	21st to end	Day	13% 5% 2 6% 4 4 4 3 3 7% 49%	3135
January	1st to 10th	Night	16% 6% 1 4 2 3 3 3 4 6% 53%	4108
	11th to 20th	Night	13% 5% 1 4 2 2 2 2 3 6% 61%	4044
	21st to end	Night	21% 6% 2 7% 4 3 3 3 6% 7% 38%	4180
February	1st to 10th	Night	12% 5% 2 5% 4 4 4 3 5% 7% 48%	2280
	11th to 20th	Night	16% 6% 2 4 3 3 3 2 4 6% 51%	2218
	21st to end	Night	12% 6% 1 5% 3 3 4 4 5% 6% 52%	1884
March	1st to 10th	Night	14% 7% 2 6% 4 4 4 4 5% 7% 42%	3489
	11th to 20th	Night	21% 8% 3 7% 5% 3 4 3 5% 6% 36%	3480
	21st to end	Night	11% 4 1 4 3 2 3 3 5% 6% 59%	3817
April	1st to 10th	Night	7% 5% 2 4 4 3 4 4 7% 9% 50%	2090
	11th to 20th	Night	10% 5% 2 5% 3 5% 3 4 6% 8% 49%	2054
	21st to end	Night	9% 7% 2 5% 5% 4 4 4 5% 8% 49%	1853
May	1st to 10th	Night	11% 5% 2 5% 3 4 3 4 7% 9% 47%	2823
	11th to 20th	Night	10% 5% 2 4 3 4 4 3 6% 8% 51%	2823
	21st to end	Night	5% 4 1 5% 4 3 4 4 7% 8% 54%	3090
June	1st to 10th	Night	2 2 1 3 3 2 4 3 5% 9% 67%	1710
	11th to 20th	Night	3 2 1 2 2 2 3 3 5% 9% 67%	1710
	21st to end	Night	4 5% 2 3 3 4 5% 3 6% 10% 55%	1710
July	1st to 10th	Night	4 3 1 3 3 4 4 4 6% 11% 57%	2850
	11th to 20th	Night	4 4 2 6% 5% 4 5% 4 7% 11% 50%	2850
	21st to end	Night	5% 3 1 5% 3 4 5% 4 7% 11% 53%	3098
August	1st to 10th	Night	1 1 1 1 1 2 2 3 6% 82%	3151
	11th to 20th	Night	1 1 1 3 3 3 4 4 7% 12% 61%	3113
	21st to end	Night	2 2 1 4 2 3 4 3 6% 11% 62%	3638
September	1st to 10th	Night	7% 5% 2 6% 5% 4 4 4 6% 9% 48%	2090
	11th to 20th	Night	8% 5% 2 5% 4 4 5% 4 7% 8% 48%	2090
	21st to end	Night	7% 4 2 5% 2 3 3 2 5% 8% 58%	2090
October	1st to 10th	Night	5% 3 1 3 2 3 4 2 5% 7% 65%	2090
	11th to 20th	Night	10% 4 2 4 3 2 2 2 5% 7% 59%	2122
	21st to end	Night	9% 4 1 3 2 2 3 2 3 5% 66%	2508
November	1st to 10th	Night	9% 6% 2 4 4 3 3 2 5% 7% 56%	2245
	11th to 20th	Night	12% 4 2 4 3 3 3 3 4 7% 55%	2374
	21st to end	Night	15% 5% 2 5% 4 3 3 3 5% 6% 50%	2470
December	1st to 10th	Night	17% 5% 2 4 3 2 3 3 4 6% 51%	2470
	11th to 20th	Night	17% 7% 2 5% 3 3 3 3 4 6% 47%	3036
	21st to end	Night	12% 5% 2 6% 3 3 4 3 5% 7% 49%	4532

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	34% 5% 5% 12% 27% 17%	2848
	11th to 20th	Day	29% 4 5% 20% 26% 17%	2954
	21st to end	Day	44% 5% 6% 15% 21% 9%	3487
February	1st to 10th	Day	42% 5% 6% 11% 19% 16%	1900
	11th to 20th	Day	36% 5% 8% 18% 19% 14%	1859
	21st to end	Day	33% 5% 9% 19% 21% 13%	1570
March	1st to 10th	Day	40% 8% 10% 19% 15% 8%	3366
	11th to 20th	Day	50% 7% 7% 10% 16% 10%	3480
	21st to end	Day	27% 6% 11% 21% 17% 18%	3814
April	1st to 10th	Day	33% 6% 12% 18% 19% 13%	2090
	11th to 20th	Day	39% 6% 10% 17% 15% 14%	2071
	21st to end	Day	34% 7% 8% 19% 18% 14%	2323
May	1st to 10th	Day	37% 9% 13% 19% 14% 7%	4120
	11th to 20th	Day	33% 10% 10% 18% 19% 10%	4086
	21st to end	Day	25% 9% 11% 39% 15% 1	4489
June	1st to 10th	Day	21% 8% 15% 30% 23% 4	2470
	11th to 20th	Day	24% 7% 12% 27% 26% 4	2470
	21st to end	Day	33% 9% 16% 26% 14% 2	2470
July	1st to 10th	Day	29% 8% 16% 38% 8% 1	4056
	11th to 20th	Day	38% 7% 17% 23% 13% 2	4051
	21st to end	Day	32% 9% 20% 28% 9% 1	4310
August	1st to 10th	Day	12% 5% 13% 42% 26% 2	3772
	11th to 20th	Day	19% 8% 25% 37% 10% 1	3762
	21st to end	Day	29% 10% 18% 26% 16% 2	4020
September	1st to 10th	Day	42% 10% 14% 17% 13% 5%	2090
	11th to 20th	Day	39% 11% 13% 18% 16% 4	2090
	21st to end	Day	30% 8% 13% 22% 15% 12%	2090
October	1st to 10th	Day	26% 7% 11% 19% 28% 9%	2090
	11th to 20th	Day	30% 6% 10% 21% 18% 16%	2038
	21st to end	Day	25% 4 7% 15% 29% 20%	2090
November	1st to 10th	Day	35% 5% 8% 19% 21% 10%	1878
	11th to 20th	Day	36% 5% 9% 18% 19% 13%	1803
	21st to end	Day	40% 5% 7% 18% 17% 13%	1710
December	1st to 10th	Day	40% 5% 8% 20% 19% 8%	1710
	11th to 20th	Day	41% 7% 8% 11% 17% 16%	2159
	21st to end	Day	35% 6% 8% 17% 24% 10%	3135
January	1st to 10th	Night	31% 6% 7% 13% 19% 23%	4108
	11th to 20th	Night	27% 4 5% 19% 23% 23%	4044
	21st to end	Night	45% 6% 6% 12% 20% 11%	4180
February	1st to 10th	Night	35% 6% 8% 15% 16% 19%	2280
	11th to 20th	Night	34% 5% 9% 17% 18% 17%	2218
	21st to end	Night	33% 5% 10% 19% 20% 14%	1884
March	1st to 10th	Night	38% 9% 12% 18% 14% 9%	3489
	11th to 20th	Night	50% 7% 11% 12% 11% 10%	3480
	21st to end	Night	23% 7% 13% 23% 21% 13%	3817
April	1st to 10th	Night	28% 8% 13% 21% 17% 13%	2090
	11th to 20th	Night	31% 8% 14% 17% 15% 15%	2054
	21st to end	Night	33% 8% 13% 18% 18% 11%	1853
May	1st to 10th	Night	31% 9% 16% 22% 14% 9%	2850
	11th to 20th	Night	28% 10% 14% 22% 19% 9%	2824
	21st to end	Night	24% 10% 15% 37% 13% 1	3099
June	1st to 10th	Night	14% 7% 20% 34% 23% 3	1710
	11th to 20th	Night	15% 6% 13% 34% 27% 4	1710
	21st to end	Night	24% 9% 20% 29% 16% 2	1710
July	1st to 10th	Night	20% 8% 25% 40% 6%	2805
	11th to 20th	Night	29% 8% 27% 25% 11%	2796
	21st to end	Night	24% 8% 28% 32% 7%	2999
August	1st to 10th	Night	6% 4 15% 49% 26% 1	3141
	11th to 20th	Night	16% 7% 32% 37% 8%	3143
	21st to end	Night	16% 10% 27% 33% 13% 1	3638
September	1st to 10th	Night	32% 10% 21% 18% 14% 5%	2090
	11th to 20th	Night	31% 10% 15% 25% 16% 3	2090
	21st to end	Night	24% 6% 13% 28% 17% 10%	2090
October	1st to 10th	Night	19% 6% 12% 28% 21% 13%	2090
	11th to 20th	Night	26% 5% 12% 23% 18% 16%	2122
	21st to end	Night	22% 4 8% 17% 26% 21%	2508
November	1st to 10th	Night	28% 6% 10% 21% 24% 11%	2245
	11th to 20th	Night	30% 6% 12% 18% 20% 13%	2374
	21st to end	Night	35% 5% 9% 21% 18% 12%	2470
December	1st to 10th	Night	35% 5% 10% 18% 21% 11%	2470
	11th to 20th	Night	38% 5% 6% 17% 15% 18%	3037
	21st to end	Night	34% 7% 9% 14% 21% 15%	4532

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	18% 11% 29% 30% 10% 1	270
	11th to 20th	Day	17% 9% 29% 33% 12% 1	270
	21st to end	Day	19% 9% 36% 23% 12% 1	297
February	1st to 10th	Day	17% 10% 33% 24% 13% 2	270
	11th to 20th	Day	16% 11% 37% 26% 9%	270
	21st to end	Day	16% 11% 39% 28% 4	225
March	1st to 10th	Day	17% 9% 37% 26% 9% 1	270
	11th to 20th	Day	17% 12% 39% 27% 6% 1	270
	21st to end	Day	12% 11% 42% 30% 5%	297
April	1st to 10th	Day	16% 9% 41% 26% 10%	270
	11th to 20th	Day	13% 9% 34% 31% 13%	269
	21st to end	Day	9% 13% 45% 28% 5%	503
May	1st to 10th	Day	9% 8% 43% 30% 8%	653
	11th to 20th	Day	11% 6% 34% 37% 10% 1	675
	21st to end	Day	6% 4 30% 44% 15% 1	734
June	1st to 10th	Day	4 1 16% 44% 31% 3	680
	11th to 20th	Day	4 1 15% 51% 25% 4	680
	21st to end	Day	5% 2 12% 40% 32% 9%	680
July	1st to 10th	Day	5% 2 11% 36% 38% 9%	671
	11th to 20th	Day	4 1 7% 39% 43% 7%	668
	21st to end	Day	3 2 6% 40% 40% 10%	736
August	1st to 10th	Day	6% 39% 40% 16%	487
	11th to 20th	Day	3 5% 36% 40% 15%	477
	21st to end	Day	5% 1 4 26% 36% 27%	445
September	1st to 10th	Day	11% 1 5% 27% 41% 16%	300
	11th to 20th	Day	8% 2 18% 44% 27%	300
	21st to end	Day	9% 2 7% 16% 42% 24%	300
October	1st to 10th	Day	7% 4 8% 29% 37% 16%	300
	11th to 20th	Day	13% 2 7% 34% 30% 14%	300
	21st to end	Day	12% 6% 21% 32% 22% 7%	330
November	1st to 10th	Day	16% 1 16% 36% 24% 7%	276
	11th to 20th	Day	17% 7% 15% 33% 23% 6%	270
	21st to end	Day	21% 9% 29% 26% 11% 3	270
December	1st to 10th	Day	21% 4 20% 30% 22% 4	270
	11th to 20th	Day	22% 9% 27% 26% 15% 1	270
	21st to end	Day	15% 8% 29% 31% 15% 2	297
January	1st to 10th	Night	19% 6% 27% 37% 10% 1	950
	11th to 20th	Night	20% 6% 31% 36% 7%	900
	21st to end	Night	19% 8% 31% 35% 7%	836
February	1st to 10th	Night	15% 10% 36% 32% 6%	760
	11th to 20th	Night	20% 8% 40% 29% 4	744
	21st to end	Night	15% 10% 47% 25% 3	628
March	1st to 10th	Night	16% 11% 45% 25% 3	618
	11th to 20th	Night	13% 11% 46% 28% 3	570
	21st to end	Night	10% 10% 56% 23% 2	627
April	1st to 10th	Night	9% 7% 58% 23% 3	570
	11th to 20th	Night	11% 9% 51% 26% 3	563
	21st to end	Night	9% 11% 51% 25% 4	570
May	1st to 10th	Night	8% 9% 58% 24% 2	570
	11th to 20th	Night	8% 7% 47% 32% 5%	561
	21st to end	Night	4 4 50% 38% 4	617
June	1st to 10th	Night	2 1 32% 51% 13% 1	570
	11th to 20th	Night	3 1 39% 49% 8%	570
	21st to end	Night	4 2 27% 51% 16% 1	570
July	1st to 10th	Night	6% 2 14% 59% 18% 1	555
	11th to 20th	Night	3 14% 65% 18%	552
	21st to end	Night	4 1 13% 65% 17% 1	624
August	1st to 10th	Night	1 14% 64% 19% 1	567
	11th to 20th	Night	3 1 14% 60% 20% 1	564
	21st to end	Night	4 1 9% 52% 31% 2	627
September	1st to 10th	Night	9% 1 10% 48% 28% 4	570
	11th to 20th	Night	11% 1 9% 41% 36% 3	570
	21st to end	Night	11% 12% 42% 30% 5%	570
October	1st to 10th	Night	5% 1 13% 51% 28% 2	570
	11th to 20th	Night	10% 1 23% 48% 16% 1	602
	21st to end	Night	10% 5% 28% 40% 17% 1	836
November	1st to 10th	Night	9% 3 24% 44% 18% 1	749
	11th to 20th	Night	13% 3 24% 43% 16% 1	854
	21st to end	Night	16% 7% 26% 37% 13% 1	950
December	1st to 10th	Night	19% 5% 21% 42% 12% 1	950
	11th to 20th	Night	23% 5% 27% 35% 9% 1	950
	21st to end	Night	16% 7% 28% 38% 11%	1045

Page generated at 2024-10-31 02:39:27. Version ac07

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