Figueroa Lookout
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Figueroa Lookout clear sky chart from 2005-11-06 to 2024-04-03.

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	5% 3 1 3 3 2 3 3 4 6% 67%	79052
	Night	6% 4 2 3 3 2 3 3 4 6% 65%	81115
Transparency	Day	19% 4 8% 19% 28% 22%	78771
	Night	20% 5% 8% 17% 26% 23%	80918
Seeing	Day	8% 10% 26% 35% 17% 4	14747
	Night	6% 5% 16% 34% 31% 8%	24525

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	7% 5% 2 4 4 2 3 3 4 6% 60%	2671
	11th to 20th	Day	9% 6% 2 4 4 2 4 5% 5% 9% 49%	2860
	21st to end	Day	11% 6% 2 5% 5% 3 5% 4 6% 7% 45%	3146
February	1st to 10th	Day	13% 5% 2 3 3 2 2 3 4 5% 57%	1859
	11th to 20th	Day	8% 5% 2 4 4 2 3 4 6% 8% 54%	1850
	21st to end	Day	11% 6% 3 4 4 2 4 4 4 5% 54%	1570
March	1st to 10th	Day	12% 5% 3 6% 5% 4 5% 5% 5% 8% 44%	1905
	11th to 20th	Day	8% 7% 2 4 3 2 3 4 5% 8% 53%	2090
	21st to end	Day	7% 4 2 4 3 3 4 5% 5% 7% 55%	2433
April	1st to 10th	Day	8% 4 2 4 3 2 3 5% 5% 8% 55%	2185
	11th to 20th	Day	5% 3 2 3 3 1 3 4 4 6% 65%	2129
	21st to end	Day	6% 2 1 2 3 2 3 4 4 6% 67%	2160
May	1st to 10th	Day	5% 3 1 2 3 1 2 3 4 7% 67%	2160
	11th to 20th	Day	2 2 1 2 2 2 3 3 4 7% 72%	2223
	21st to end	Day	3 2 1 3 3 2 3 3 5% 6% 69%	2633
June	1st to 10th	Day	3 2 1 2 2 2 2 3 4 6% 73%	2520
	11th to 20th	Day	1 2 1 1 1 1 2 3 5% 83%	2520
	21st to end	Day	1 1 1 1 1 1 2 2 4 86%	2520
July	1st to 10th	Day	1 1 1 1 1 1 2 2 4 4 83%	2520
	11th to 20th	Day	2 1 1 2 2 2 2 2 3 5% 78%	2386
	21st to end	Day	2 1 1 2 2 2 3 2 4 7% 75%	2546
August	1st to 10th	Day	1 1 1 2 1 1 2 2 3 4 81%	2152
	11th to 20th	Day	1 1 1 1 1 1 1 3 4 87%	2122
	21st to end	Day	1 1 1 2 1 1 2 2 3 4 83%	2376
September	1st to 10th	Day	1 1 1 1 1 1 2 3 4 83%	2160
	11th to 20th	Day	1 1 2 1 2 1 3 3 85%	2124
	21st to end	Day	1 1 1 1 2 1 1 2 3 5% 83%	1980
October	1st to 10th	Day	3 2 1 3 2 2 3 3 4 4 73%	1867
	11th to 20th	Day	2 2 1 2 2 2 2 2 4 4 76%	1800
	21st to end	Day	2 2 1 2 3 2 3 4 3 6% 73%	1980
November	1st to 10th	Day	5% 4 1 3 3 2 3 3 4 5% 68%	1756
	11th to 20th	Day	4 3 1 2 3 2 4 3 4 6% 68%	1710
	21st to end	Day	5% 3 2 5% 4 2 4 4 5% 8% 59%	1710
December	1st to 10th	Day	8% 5% 2 5% 4 2 3 4 4 7% 56%	1707
	11th to 20th	Day	18% 8% 3 5% 5% 2 3 5% 5% 5% 41%	1928
	21st to end	Day	13% 8% 2 5% 5% 2 4 3 5% 7% 45%	2794
January	1st to 10th	Night	8% 6% 2 4 4 3 3 3 4 6% 57%	4273
	11th to 20th	Night	8% 7% 4 5% 4 3 4 4 5% 8% 49%	4110
	21st to end	Night	13% 8% 2 4 5% 3 4 4 5% 8% 45%	4521
February	1st to 10th	Night	10% 6% 3 4 4 2 2 3 4 6% 56%	2318
	11th to 20th	Night	8% 4 2 4 4 2 3 4 5% 8% 57%	2218
	21st to end	Night	9% 7% 2 5% 4 3 4 3 4 5% 56%	1884
March	1st to 10th	Night	9% 7% 3 4 4 3 5% 5% 8% 7% 44%	2271
	11th to 20th	Night	7% 6% 2 4 5% 3 5% 5% 5% 7% 51%	2090
	21st to end	Night	8% 5% 1 3 3 2 4 3 5% 7% 59%	2163
April	1st to 10th	Night	7% 4 2 3 4 2 4 4 5% 7% 60%	1820
	11th to 20th	Night	6% 2 1 2 3 2 3 3 4 5% 69%	1779
	21st to end	Night	3 2 1 2 2 2 3 3 4 7% 70%	1800
May	1st to 10th	Night	2 2 1 2 3 2 2 3 5% 7% 72%	1800
	11th to 20th	Night	3 2 1 2 2 1 2 2 4 6% 75%	1671
	21st to end	Night	1 2 2 3 2 2 2 3 3 5% 75%	1637
June	1st to 10th	Night	1 1 1 2 2 2 3 3 4 6% 76%	1440
	11th to 20th	Night	1 1 1 1 1 1 2 2 2 3 86%	1440
	21st to end	Night	1 1 1 1 1 2 3 90%	1440
July	1st to 10th	Night	1 2 1 2 2 4 5% 83%	1440
	11th to 20th	Night	1 1 2 1 2 2 4 4 83%	1570
	21st to end	Night	1 1 1 2 2 1 2 2 3 4 80%	1773
August	1st to 10th	Night	1 1 1 1 2 1 1 2 2 3 86%	1785
	11th to 20th	Night	1 1 1 1 2 2 4 4 86%	1780
	21st to end	Night	1 1 1 1 1 1 1 2 2 89%	1980
September	1st to 10th	Night	1 1 1 1 1 1 1 3 4 85%	1800
	11th to 20th	Night	1 1 1 1 1 2 2 2 4 84%	1836
	21st to end	Night	1 1 1 1 2 2 3 4 85%	1980
October	1st to 10th	Night	3 2 1 2 2 1 3 3 3 4 76%	2090
	11th to 20th	Night	3 2 2 3 3 2 2 3 4 4 73%	2160
	21st to end	Night	2 2 1 2 2 2 2 2 3 5% 77%	2376
November	1st to 10th	Night	3 3 1 2 3 2 4 3 4 6% 67%	2323
	11th to 20th	Night	3 3 1 3 3 2 3 4 4 7% 67%	2470
	21st to end	Night	5% 4 2 4 4 3 4 3 5% 7% 60%	2470
December	1st to 10th	Night	7% 4 2 4 3 2 4 4 5% 7% 57%	2470
	11th to 20th	Night	17% 8% 3 5% 5% 2 4 4 5% 7% 40%	3275
	21st to end	Night	11% 7% 2 6% 6% 3 4 5% 5% 8% 43%	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	22% 5% 7% 30% 28% 7%	2671
	11th to 20th	Day	30% 8% 11% 18% 22% 12%	2860
	21st to end	Day	34% 6% 10% 23% 17% 10%	3146
February	1st to 10th	Day	29% 3 6% 18% 23% 20%	1859
	11th to 20th	Day	26% 5% 8% 21% 26% 13%	1860
	21st to end	Day	31% 5% 8% 21% 26% 9%	1570
March	1st to 10th	Day	35% 6% 10% 19% 19% 11%	1905
	11th to 20th	Day	28% 5% 13% 21% 22% 11%	2090
	21st to end	Day	25% 7% 13% 27% 20% 7%	2433
April	1st to 10th	Day	25% 6% 14% 22% 23% 10%	2185
	11th to 20th	Day	20% 4 10% 29% 27% 10%	2132
	21st to end	Day	18% 5% 10% 26% 32% 9%	2160
May	1st to 10th	Day	18% 4 13% 22% 33% 11%	2160
	11th to 20th	Day	13% 4 12% 29% 30% 12%	2226
	21st to end	Day	16% 5% 13% 30% 29% 7%	2633
June	1st to 10th	Day	14% 5% 10% 23% 33% 15%	2520
	11th to 20th	Day	8% 3 7% 15% 36% 30%	2520
	21st to end	Day	6% 2 5% 11% 34% 41%	2520
July	1st to 10th	Day	7% 2 5% 13% 29% 44%	2451
	11th to 20th	Day	11% 3 6% 16% 31% 33%	2314
	21st to end	Day	11% 5% 8% 18% 32% 26%	2405
August	1st to 10th	Day	9% 3 5% 12% 32% 39%	2137
	11th to 20th	Day	5% 2 5% 15% 33% 40%	2122
	21st to end	Day	8% 2 5% 12% 35% 39%	2376
September	1st to 10th	Day	7% 2 6% 12% 29% 44%	2160
	11th to 20th	Day	7% 3 4 17% 35% 34%	2124
	21st to end	Day	7% 2 5% 17% 39% 30%	1980
October	1st to 10th	Day	14% 3 8% 17% 26% 32%	1867
	11th to 20th	Day	14% 3 6% 14% 31% 33%	1800
	21st to end	Day	13% 4 7% 13% 28% 35%	1980
November	1st to 10th	Day	18% 3 6% 16% 31% 26%	1756
	11th to 20th	Day	19% 3 8% 16% 27% 28%	1710
	21st to end	Day	23% 4 8% 15% 24% 25%	1710
December	1st to 10th	Day	29% 4 7% 18% 22% 21%	1707
	11th to 20th	Day	43% 6% 8% 15% 17% 11%	1928
	21st to end	Day	36% 8% 8% 24% 16% 9%	2794
January	1st to 10th	Night	25% 5% 8% 21% 29% 11%	4273
	11th to 20th	Night	31% 8% 9% 18% 20% 14%	4110
	21st to end	Night	33% 8% 9% 18% 20% 12%	4521
February	1st to 10th	Night	28% 5% 7% 16% 24% 21%	2318
	11th to 20th	Night	24% 5% 7% 20% 27% 17%	2219
	21st to end	Night	30% 5% 7% 20% 25% 13%	1884
March	1st to 10th	Night	33% 7% 12% 21% 18% 10%	2271
	11th to 20th	Night	28% 6% 11% 19% 22% 13%	2090
	21st to end	Night	23% 6% 14% 23% 24% 10%	2163
April	1st to 10th	Night	24% 6% 13% 25% 22% 11%	1820
	11th to 20th	Night	17% 4 12% 25% 30% 12%	1779
	21st to end	Night	15% 5% 12% 24% 32% 11%	1800
May	1st to 10th	Night	12% 5% 14% 24% 28% 17%	1800
	11th to 20th	Night	12% 4 11% 27% 31% 15%	1672
	21st to end	Night	13% 5% 12% 28% 32% 10%	1637
June	1st to 10th	Night	10% 5% 13% 22% 32% 19%	1440
	11th to 20th	Night	8% 3 8% 13% 34% 35%	1440
	21st to end	Night	5% 1 5% 12% 28% 49%	1440
July	1st to 10th	Night	7% 2 5% 10% 27% 50%	1400
	11th to 20th	Night	7% 2 6% 17% 26% 43%	1519
	21st to end	Night	9% 3 5% 17% 30% 36%	1674
August	1st to 10th	Night	8% 1 4 9% 27% 52%	1776
	11th to 20th	Night	5% 1 3 13% 31% 46%	1780
	21st to end	Night	5% 1 3 9% 34% 47%	1980
September	1st to 10th	Night	6% 2 6% 10% 26% 50%	1800
	11th to 20th	Night	7% 3 4 11% 36% 38%	1836
	21st to end	Night	6% 3 5% 12% 40% 34%	1980
October	1st to 10th	Night	12% 2 7% 17% 26% 36%	2090
	11th to 20th	Night	15% 5% 6% 14% 27% 34%	2160
	21st to end	Night	14% 2 5% 13% 30% 37%	2376
November	1st to 10th	Night	18% 4 6% 16% 31% 26%	2323
	11th to 20th	Night	18% 4 9% 15% 24% 31%	2470
	21st to end	Night	23% 4 9% 17% 21% 26%	2470
December	1st to 10th	Night	26% 5% 8% 16% 22% 24%	2470
	11th to 20th	Night	43% 5% 9% 15% 17% 12%	3275
	21st to end	Night	36% 9% 10% 19% 18% 9%	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	22% 14% 30% 24% 9% 1	260
	11th to 20th	Day	18% 12% 28% 30% 10% 1	370
	21st to end	Day	14% 14% 36% 24% 10% 2	407
February	1st to 10th	Day	16% 15% 26% 27% 13% 4	441
	11th to 20th	Day	17% 16% 29% 26% 10% 2	455
	21st to end	Day	14% 17% 37% 23% 8% 1	382
March	1st to 10th	Day	21% 19% 30% 23% 7%	460
	11th to 20th	Day	18% 16% 33% 26% 7% 1	460
	21st to end	Day	17% 23% 31% 23% 6%	506
April	1st to 10th	Day	13% 15% 36% 22% 12% 2	429
	11th to 20th	Day	11% 17% 39% 22% 8% 2	412
	21st to end	Day	8% 18% 34% 25% 13% 3	420
May	1st to 10th	Day	14% 12% 33% 26% 12% 3	423
	11th to 20th	Day	6% 11% 34% 33% 13% 3	448
	21st to end	Day	8% 12% 34% 31% 10% 4	485
June	1st to 10th	Day	4 9% 25% 36% 22% 5%	450
	11th to 20th	Day	4 7% 23% 43% 18% 5%	450
	21st to end	Day	1 3 24% 42% 25% 6%	450
July	1st to 10th	Day	1 14% 49% 29% 7%	446
	11th to 20th	Day	2 1 10% 45% 30% 11%	444
	21st to end	Day	3 10% 47% 27% 13%	487
August	1st to 10th	Day	2 1 18% 48% 24% 7%	447
	11th to 20th	Day	2 12% 47% 31% 8%	437
	21st to end	Day	1 1 12% 50% 29% 6%	495
September	1st to 10th	Day	2 3 18% 48% 24% 5%	450
	11th to 20th	Day	2 5% 26% 46% 17% 3	450
	21st to end	Day	1 6% 24% 42% 22% 3	450
October	1st to 10th	Day	2 10% 28% 38% 21% 2	450
	11th to 20th	Day	4 9% 27% 39% 18% 3	450
	21st to end	Day	5% 9% 26% 35% 21% 5%	495
November	1st to 10th	Day	6% 11% 25% 36% 18% 3	352
	11th to 20th	Day	10% 8% 24% 35% 19% 4	270
	21st to end	Day	8% 10% 24% 33% 19% 5%	270
December	1st to 10th	Day	10% 14% 28% 30% 16% 1	268
	11th to 20th	Day	11% 16% 23% 26% 20% 4	180
	21st to end	Day	21% 15% 30% 24% 8% 2	198
January	1st to 10th	Night	15% 6% 21% 31% 17% 10%	760
	11th to 20th	Night	8% 6% 23% 34% 21% 8%	760
	21st to end	Night	13% 8% 25% 35% 15% 5%	836
February	1st to 10th	Night	14% 8% 19% 31% 23% 6%	760
	11th to 20th	Night	10% 9% 21% 35% 17% 7%	744
	21st to end	Night	12% 10% 25% 33% 17% 3	628
March	1st to 10th	Night	14% 8% 24% 33% 19% 3	760
	11th to 20th	Night	10% 6% 21% 36% 23% 4	760
	21st to end	Night	9% 10% 22% 38% 18% 3	836
April	1st to 10th	Night	8% 6% 25% 40% 19% 3	728
	11th to 20th	Night	7% 7% 24% 34% 23% 5%	711
	21st to end	Night	4 7% 24% 35% 22% 7%	720
May	1st to 10th	Night	3 6% 20% 37% 28% 6%	720
	11th to 20th	Night	5% 4 16% 38% 34% 4	608
	21st to end	Night	3 7% 17% 39% 32% 3	475
June	1st to 10th	Night	1 2 10% 38% 43% 6%	360
	11th to 20th	Night	1 1 10% 33% 47% 8%	360
	21st to end	Night	5% 36% 52% 7%	360
July	1st to 10th	Night	2 25% 61% 12%	350
	11th to 20th	Night	1 15% 64% 20%	475
	21st to end	Night	2 1 1 18% 62% 18%	591
August	1st to 10th	Night	1 6% 29% 50% 13%	711
	11th to 20th	Night	1 2 25% 59% 14%	712
	21st to end	Night	1 2 28% 54% 16%	792
September	1st to 10th	Night	1 1 4 30% 50% 13%	720
	11th to 20th	Night	2 1 8% 40% 39% 10%	720
	21st to end	Night	1 1 10% 37% 40% 11%	720
October	1st to 10th	Night	3 3 10% 44% 34% 6%	720
	11th to 20th	Night	4 3 14% 39% 32% 8%	720
	21st to end	Night	3 4 15% 37% 29% 11%	792
November	1st to 10th	Night	6% 4 19% 37% 25% 9%	740
	11th to 20th	Night	5% 4 17% 39% 27% 8%	760
	21st to end	Night	7% 5% 20% 39% 20% 8%	760
December	1st to 10th	Night	9% 7% 19% 36% 23% 6%	760
	11th to 20th	Night	13% 7% 20% 39% 17% 4	760
	21st to end	Night	12% 10% 22% 36% 15% 5%	836

Page generated at 2024-03-31 03:08:49. Version ac07

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