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 2025-09-04.

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	4 3 1 3 2 2 2 2 4 5% 73%	134051
	Night	4 4 1 3 2 2 3 2 4 5% 69%	132179
Transparency	Day	16% 3 7% 19% 29% 26%	129132
	Night	17% 4 7% 16% 26% 29%	128074
Seeing	Day	8% 10% 27% 34% 17% 4	16706
	Night	6% 5% 17% 35% 30% 7%	26348

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	5% 4 2 4 2 2 3 2 3 6% 67%	3841
	11th to 20th	Day	6% 4 1 3 2 3 3 3 4 6% 65%	4100
	21st to end	Day	8% 6% 2 5% 3 4 4 3 6% 8% 50%	4510
February	1st to 10th	Day	13% 5% 2 4 3 3 2 3 4 5% 56%	1957
	11th to 20th	Day	8% 6% 2 4 3 3 4 3 5% 8% 54%	1950
	21st to end	Day	10% 7% 2 4 4 3 3 3 4 5% 54%	1650
March	1st to 10th	Day	14% 7% 2 6% 3 3 4 3 4 6% 46%	4535
	11th to 20th	Day	9% 7% 2 5% 2 3 3 2 3 5% 59%	5000
	21st to end	Day	8% 7% 2 5% 4 4 4 4 6% 9% 47%	5806
April	1st to 10th	Day	7% 5% 1 4 3 3 3 4 6% 8% 56%	2400
	11th to 20th	Day	5% 4 2 3 3 2 2 3 5% 6% 64%	2369
	21st to end	Day	5% 2 1 2 3 3 3 3 4 6% 66%	2400
May	1st to 10th	Day	3 2 1 2 1 1 2 2 3 5% 78%	5440
	11th to 20th	Day	1 1 1 1 2 2 2 4 5% 81%	5659
	21st to end	Day	1 1 1 2 1 2 2 2 3 5% 81%	6682
June	1st to 10th	Day	3 2 1 2 2 2 2 3 4 6% 74%	2800
	11th to 20th	Day	1 2 1 1 1 1 2 3 5% 84%	2800
	21st to end	Day	1 1 1 1 1 1 2 4 87%	2800
July	1st to 10th	Day	1 1 1 1 2 2 93%	6319
	11th to 20th	Day	1 1 1 1 1 1 1 2 3 86%	5978
	21st to end	Day	1 1 1 1 1 1 1 3 4 87%	6402
August	1st to 10th	Day	1 1 1 1 1 1 2 3 5% 84%	5349
	11th to 20th	Day	1 1 1 2 94%	5364
	21st to end	Day	1 1 1 1 1 1 2 3 89%	5981
September	1st to 10th	Day	1 1 2 1 1 1 2 3 4 84%	2317
	11th to 20th	Day	1 2 1 1 2 1 3 3 85%	2242
	21st to end	Day	1 1 1 1 1 1 2 2 4 84%	2090
October	1st to 10th	Day	2 1 1 3 1 2 2 2 3 3 79%	3286
	11th to 20th	Day	1 1 1 2 2 2 2 2 3 3 81%	3161
	21st to end	Day	3 3 1 3 2 3 3 2 4 5% 71%	3448
November	1st to 10th	Day	4 4 1 3 3 2 2 2 4 5% 69%	1850
	11th to 20th	Day	4 3 1 3 3 3 4 3 4 6% 68%	1800
	21st to end	Day	6% 4 2 6% 4 4 3 3 5% 7% 57%	1800
December	1st to 10th	Day	5% 4 2 6% 3 3 3 3 4 6% 61%	2933
	11th to 20th	Day	13% 6% 2 5% 4 4 4 4 5% 5% 50%	3028
	21st to end	Day	11% 7% 2 5% 4 3 3 3 7% 9% 47%	4004
January	1st to 10th	Night	6% 5% 2 4 2 3 3 3 5% 6% 62%	6108
	11th to 20th	Night	6% 5% 2 4 2 3 3 2 3 5% 64%	5880
	21st to end	Night	9% 7% 2 5% 4 4 4 3 4 7% 51%	6468
February	1st to 10th	Night	10% 7% 2 4 4 3 2 3 5% 6% 55%	2440
	11th to 20th	Night	8% 5% 2 4 4 3 3 4 6% 8% 56%	2338
	21st to end	Night	8% 7% 2 5% 3 3 3 2 3 5% 57%	1980
March	1st to 10th	Night	9% 11% 3 6% 3 4 4 4 7% 7% 43%	5342
	11th to 20th	Night	6% 7% 2 5% 4 4 3 3 5% 5% 56%	5000
	21st to end	Night	9% 7% 2 5% 3 3 3 3 5% 7% 52%	5167
April	1st to 10th	Night	6% 4 2 4 4 3 3 3 5% 6% 61%	2000
	11th to 20th	Night	5% 3 1 3 3 2 3 2 4 6% 68%	1979
	21st to end	Night	3 3 1 3 2 2 3 3 4 8% 69%	2000
May	1st to 10th	Night	1 1 2 1 2 2 2 4 5% 79%	4560
	11th to 20th	Night	1 1 1 1 1 2 2 4 6% 80%	4263
	21st to end	Night	1 1 1 1 1 1 1 1 2 3 88%	4183
June	1st to 10th	Night	1 1 1 2 2 2 3 3 4 6% 77%	1600
	11th to 20th	Night	1 1 1 1 1 1 2 1 2 3 86%	1600
	21st to end	Night	1 1 1 1 1 2 3 90%	1600
July	1st to 10th	Night	1 1 1 2 2 93%	3640
	11th to 20th	Night	1 1 1 1 1 2 4 89%	3994
	21st to end	Night	1 1 1 1 1 1 3 4 87%	4472
August	1st to 10th	Night	1 1 1 1 1 1 2 4 88%	4481
	11th to 20th	Night	1 1 2 2 94%	4506
	21st to end	Night	1 1 1 1 1 2 2 91%	5015
September	1st to 10th	Night	1 1 1 1 1 1 1 3 4 85%	1930
	11th to 20th	Night	1 1 1 2 1 2 1 1 2 4 84%	1938
	21st to end	Night	1 1 1 2 2 1 3 3 85%	2090
October	1st to 10th	Night	1 1 1 2 1 1 2 1 2 3 83%	3691
	11th to 20th	Night	2 1 1 2 1 1 2 2 4 4 80%	3777
	21st to end	Night	3 3 1 2 2 2 2 1 3 5% 77%	4121
November	1st to 10th	Night	3 3 1 3 2 3 3 2 4 6% 68%	2449
	11th to 20th	Night	3 3 1 3 2 3 3 3 4 6% 68%	2600
	21st to end	Night	5% 5% 2 4 4 4 4 3 5% 6% 58%	2600
December	1st to 10th	Night	4 3 1 4 3 3 4 3 6% 6% 62%	4240
	11th to 20th	Night	11% 6% 2 5% 4 4 5% 4 6% 7% 47%	5175
	21st to end	Night	8% 6% 2 6% 5% 4 5% 5% 7% 11% 41%	6952

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	18% 3 6% 26% 31% 16%	3841
	11th to 20th	Day	21% 5% 8% 13% 22% 32%	4100
	21st to end	Day	29% 5% 9% 17% 23% 18%	4510
February	1st to 10th	Day	29% 3 7% 18% 24% 19%	1957
	11th to 20th	Day	26% 5% 8% 22% 26% 13%	1960
	21st to end	Day	30% 5% 7% 21% 26% 11%	1650
March	1st to 10th	Day	34% 5% 11% 18% 24% 8%	4535
	11th to 20th	Day	28% 3 11% 26% 23% 9%	5000
	21st to end	Day	28% 9% 13% 29% 18% 3	5806
April	1st to 10th	Day	24% 6% 13% 22% 25% 9%	2400
	11th to 20th	Day	20% 4 10% 30% 27% 9%	2372
	21st to end	Day	18% 5% 11% 27% 31% 8%	2400
May	1st to 10th	Day	10% 3 9% 28% 35% 15%	5440
	11th to 20th	Day	8% 4 12% 26% 38% 12%	5662
	21st to end	Day	8% 3 8% 33% 37% 11%	6683
June	1st to 10th	Day	13% 5% 10% 26% 33% 14%	2800
	11th to 20th	Day	7% 3 7% 16% 37% 31%	2800
	21st to end	Day	6% 2 5% 10% 33% 44%	2800
July	1st to 10th	Day	3 1 2 6% 22% 66%	6251
	11th to 20th	Day	7% 1 3 7% 27% 54%	5906
	21st to end	Day	5% 2 4 17% 40% 33%	6217
August	1st to 10th	Day	6% 2 4 13% 38% 37%	3892
	11th to 20th	Day	3 1 3 8% 34% 52%	3880
	21st to end	Day	5% 1 3 11% 31% 49%	4311
September	1st to 10th	Day	7% 2 6% 11% 29% 45%	2317
	11th to 20th	Day	7% 3 4 17% 36% 33%	2242
	21st to end	Day	7% 2 4 16% 38% 33%	2090
October	1st to 10th	Day	11% 2 5% 11% 25% 47%	3286
	11th to 20th	Day	11% 2 4 19% 37% 27%	3161
	21st to end	Day	17% 2 5% 11% 36% 30%	3448
November	1st to 10th	Day	18% 3 6% 16% 32% 26%	1850
	11th to 20th	Day	18% 3 8% 16% 28% 27%	1800
	21st to end	Day	25% 4 8% 14% 24% 25%	1800
December	1st to 10th	Day	25% 2 5% 13% 28% 27%	2933
	11th to 20th	Day	35% 4 7% 18% 22% 13%	3028
	21st to end	Day	31% 6% 10% 26% 19% 9%	4004
January	1st to 10th	Night	21% 4 7% 20% 30% 19%	6108
	11th to 20th	Night	22% 5% 6% 13% 18% 36%	5880
	21st to end	Night	30% 6% 7% 14% 22% 22%	6468
February	1st to 10th	Night	28% 5% 7% 16% 24% 20%	2440
	11th to 20th	Night	24% 5% 7% 21% 26% 16%	2339
	21st to end	Night	29% 5% 7% 19% 25% 15%	1980
March	1st to 10th	Night	34% 6% 10% 19% 22% 8%	5342
	11th to 20th	Night	28% 6% 11% 23% 23% 11%	5000
	21st to end	Night	27% 8% 13% 25% 22% 5%	5167
April	1st to 10th	Night	23% 6% 12% 25% 24% 11%	2000
	11th to 20th	Night	17% 5% 12% 23% 30% 12%	1979
	21st to end	Night	15% 5% 12% 25% 32% 11%	2000
May	1st to 10th	Night	8% 5% 11% 22% 33% 21%	4557
	11th to 20th	Night	7% 5% 10% 26% 30% 22%	4264
	21st to end	Night	5% 4 8% 22% 40% 21%	4183
June	1st to 10th	Night	9% 5% 13% 23% 33% 18%	1600
	11th to 20th	Night	8% 2 7% 12% 34% 37%	1600
	21st to end	Night	4 1 5% 11% 27% 52%	1600
July	1st to 10th	Night	3 1 2 5% 14% 75%	3600
	11th to 20th	Night	4 1 4 7% 17% 67%	3943
	21st to end	Night	4 1 4 13% 32% 47%	4345
August	1st to 10th	Night	6% 1 3 9% 31% 50%	3252
	11th to 20th	Night	3 1 2 7% 21% 66%	3256
	21st to end	Night	3 1 2 8% 25% 61%	3608
September	1st to 10th	Night	6% 2 6% 9% 26% 51%	1930
	11th to 20th	Night	8% 3 4 11% 37% 37%	1938
	21st to end	Night	6% 2 5% 11% 39% 37%	2090
October	1st to 10th	Night	8% 1 4 10% 20% 57%	3691
	11th to 20th	Night	9% 3 4 14% 34% 36%	3777
	21st to end	Night	13% 2 3 10% 37% 35%	4121
November	1st to 10th	Night	17% 3 5% 16% 32% 26%	2449
	11th to 20th	Night	17% 3 9% 15% 25% 30%	2600
	21st to end	Night	24% 4 9% 17% 20% 25%	2600
December	1st to 10th	Night	21% 3 6% 12% 26% 32%	4240
	11th to 20th	Night	35% 4 9% 16% 22% 14%	5175
	21st to end	Night	33% 7% 12% 21% 20% 7%	6952

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	21% 15% 29% 24% 10% 1	285
	11th to 20th	Day	17% 13% 30% 29% 10% 2	400
	21st to end	Day	14% 14% 36% 24% 10% 2	440
February	1st to 10th	Day	17% 15% 27% 25% 12% 4	479
	11th to 20th	Day	19% 16% 29% 25% 9% 2	495
	21st to end	Day	13% 17% 38% 24% 7% 1	414
March	1st to 10th	Day	23% 19% 30% 22% 7%	500
	11th to 20th	Day	20% 16% 33% 24% 6% 1	500
	21st to end	Day	16% 23% 31% 23% 6%	550
April	1st to 10th	Day	14% 16% 34% 22% 12% 2	500
	11th to 20th	Day	11% 17% 38% 23% 9% 2	492
	21st to end	Day	8% 17% 32% 27% 13% 3	500
May	1st to 10th	Day	13% 11% 36% 26% 11% 3	503
	11th to 20th	Day	6% 11% 34% 33% 13% 3	528
	21st to end	Day	7% 11% 35% 32% 12% 3	573
June	1st to 10th	Day	4 9% 25% 37% 21% 5%	530
	11th to 20th	Day	4 7% 27% 40% 18% 5%	530
	21st to end	Day	1 3 24% 42% 24% 6%	530
July	1st to 10th	Day	1 1 15% 48% 28% 7%	526
	11th to 20th	Day	2 1 11% 45% 29% 12%	524
	21st to end	Day	3 13% 46% 26% 13%	575
August	1st to 10th	Day	2 1 19% 47% 24% 7%	527
	11th to 20th	Day	2 1 15% 47% 28% 8%	517
	21st to end	Day	1 1 15% 49% 27% 7%	583
September	1st to 10th	Day	2 3 20% 47% 24% 5%	503
	11th to 20th	Day	3 6% 28% 44% 16% 3	490
	21st to end	Day	1 6% 26% 41% 22% 3	490
October	1st to 10th	Day	2 9% 26% 38% 22% 3	490
	11th to 20th	Day	4 9% 27% 39% 18% 3	490
	21st to end	Day	5% 9% 28% 34% 20% 4	539
November	1st to 10th	Day	7% 11% 25% 36% 18% 3	386
	11th to 20th	Day	11% 10% 26% 33% 17% 3	300
	21st to end	Day	10% 9% 27% 31% 18% 5%	300
December	1st to 10th	Day	9% 12% 27% 32% 17% 2	297
	11th to 20th	Day	12% 16% 24% 26% 19% 4	200
	21st to end	Day	22% 15% 30% 24% 7% 2	220
January	1st to 10th	Night	14% 7% 22% 31% 16% 10%	800
	11th to 20th	Night	8% 7% 25% 34% 20% 8%	800
	21st to end	Night	13% 8% 25% 35% 15% 5%	880
February	1st to 10th	Night	14% 8% 20% 30% 22% 5%	800
	11th to 20th	Night	11% 9% 22% 34% 17% 7%	784
	21st to end	Night	12% 10% 27% 32% 16% 3	660
March	1st to 10th	Night	14% 9% 24% 33% 18% 2	800
	11th to 20th	Night	11% 7% 21% 35% 22% 4	800
	21st to end	Night	10% 10% 23% 37% 17% 3	880
April	1st to 10th	Night	8% 7% 25% 39% 19% 3	800
	11th to 20th	Night	6% 8% 24% 36% 22% 4	791
	21st to end	Night	4 7% 25% 35% 22% 7%	800
May	1st to 10th	Night	3 6% 22% 37% 27% 5%	800
	11th to 20th	Night	5% 4 18% 37% 32% 4	676
	21st to end	Night	2 6% 17% 41% 31% 2	528
June	1st to 10th	Night	1 2 9% 40% 43% 5%	400
	11th to 20th	Night	1 2 12% 35% 44% 7%	400
	21st to end	Night	1 6% 37% 49% 7%	400
July	1st to 10th	Night	2 27% 60% 11%	390
	11th to 20th	Night	1 1 16% 62% 20%	531
	21st to end	Night	2 1 19% 61% 16%	657
August	1st to 10th	Night	1 1 6% 30% 50% 12%	791
	11th to 20th	Night	1 3 28% 56% 12%	792
	21st to end	Night	1 3 31% 51% 14%	880
September	1st to 10th	Night	1 1 5% 32% 48% 12%	772
	11th to 20th	Night	2 2 9% 40% 38% 10%	760
	21st to end	Night	1 1 10% 40% 38% 10%	760
October	1st to 10th	Night	3 3 10% 45% 33% 6%	760
	11th to 20th	Night	4 3 15% 39% 32% 8%	760
	21st to end	Night	4 5% 16% 38% 28% 11%	836
November	1st to 10th	Night	6% 5% 20% 37% 24% 9%	780
	11th to 20th	Night	5% 6% 18% 38% 25% 7%	800
	21st to end	Night	7% 5% 23% 38% 19% 8%	800
December	1st to 10th	Night	9% 7% 20% 36% 23% 5%	800
	11th to 20th	Night	12% 7% 21% 39% 17% 4	800
	21st to end	Night	12% 11% 23% 35% 15% 5%	880

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