Yaquina Bay State Recreation Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Yaquina Bay State Recreation Site clear sky chart from 2005-11-06 to 2024-03-06.

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	25% 9% 3 6% 5% 3 4 4 4 6% 31%	78864
	Night	28% 11% 3 6% 5% 3 4 4 4 5% 28%	80670
Transparency	Day	39% 36% 8% 10% 6% 1	78572
	Night	42% 35% 7% 9% 5% 2	80483
Seeing	Day	26% 11% 24% 26% 12% 3	14145
	Night	31% 7% 14% 26% 18% 3	22924

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	40% 18% 4 8% 5% 3 3 3 3 3 11%	2539
	11th to 20th	Day	42% 10% 3 5% 5% 2 3 2 2 4 21%	2636
	21st to end	Day	41% 10% 3 6% 5% 3 4 4 4 4 15%	3146
February	1st to 10th	Day	36% 11% 4 7% 6% 3 4 3 3 6% 16%	1710
	11th to 20th	Day	32% 12% 3 7% 6% 4 4 4 5% 4 18%	1665
	21st to end	Day	32% 15% 5% 7% 5% 3 3 4 3 5% 17%	1441
March	1st to 10th	Day	33% 13% 5% 6% 6% 3 4 4 4 6% 15%	2022
	11th to 20th	Day	36% 11% 3 6% 6% 3 5% 3 4 5% 18%	1980
	21st to end	Day	37% 11% 4 7% 6% 3 4 4 4 5% 14%	2178
April	1st to 10th	Day	33% 12% 5% 7% 6% 3 5% 4 5% 6% 15%	2150
	11th to 20th	Day	29% 11% 4 7% 7% 3 4 4 4 6% 21%	2175
	21st to end	Day	28% 9% 3 6% 5% 3 5% 6% 5% 7% 23%	2340
May	1st to 10th	Day	21% 9% 4 7% 5% 3 4 4 4 7% 31%	2383
	11th to 20th	Day	23% 11% 3 7% 5% 3 4 5% 6% 8% 25%	2477
	21st to end	Day	26% 8% 3 7% 5% 3 5% 5% 6% 8% 24%	2723
June	1st to 10th	Day	28% 8% 3 5% 5% 3 4 3 5% 7% 29%	2520
	11th to 20th	Day	22% 8% 3 6% 6% 3 5% 5% 6% 8% 29%	2564
	21st to end	Day	14% 7% 2 5% 4 3 3 3 5% 8% 45%	2700
July	1st to 10th	Day	9% 6% 2 4 5% 3 4 4 5% 8% 50%	2620
	11th to 20th	Day	13% 6% 2 4 3 1 2 3 4 7% 54%	2520
	21st to end	Day	6% 5% 2 3 3 2 3 3 5% 7% 61%	2643
August	1st to 10th	Day	8% 10% 3 6% 4 3 4 3 5% 8% 48%	2328
	11th to 20th	Day	8% 6% 3 4 4 2 4 4 4 8% 53%	2298
	21st to end	Day	8% 7% 2 5% 4 3 4 4 5% 9% 50%	2490
September	1st to 10th	Day	7% 5% 2 4 3 2 3 4 4 7% 58%	2160
	11th to 20th	Day	12% 8% 3 5% 5% 3 3 5% 5% 9% 42%	2084
	21st to end	Day	19% 7% 2 4 4 2 4 4 5% 6% 42%	1940
October	1st to 10th	Day	21% 8% 3 5% 5% 2 3 4 4 6% 39%	1800
	11th to 20th	Day	22% 8% 3 5% 6% 3 4 4 4 6% 34%	1800
	21st to end	Day	29% 9% 2 5% 5% 3 3 3 4 5% 31%	1980
November	1st to 10th	Day	34% 10% 4 7% 6% 3 3 5% 5% 5% 19%	1570
	11th to 20th	Day	35% 9% 3 5% 6% 3 4 4 5% 6% 22%	1520
	21st to end	Day	32% 9% 3 6% 5% 3 4 4 4 5% 24%	1520
December	1st to 10th	Day	30% 9% 3 7% 6% 2 3 3 4 5% 28%	1520
	11th to 20th	Day	35% 11% 3 7% 6% 3 4 4 4 5% 18%	1928
	21st to end	Day	41% 14% 3 6% 4 2 3 3 4 4 14%	2794
January	1st to 10th	Night	38% 17% 4 7% 6% 3 4 4 2 4 11%	4406
	11th to 20th	Night	39% 14% 4 6% 4 2 3 3 3 4 19%	4323
	21st to end	Night	47% 12% 3 5% 4 2 3 3 3 4 15%	4521
February	1st to 10th	Night	33% 12% 4 7% 7% 3 4 5% 4 5% 16%	2470
	11th to 20th	Night	30% 13% 3 8% 5% 2 3 4 4 4 23%	2402
	21st to end	Night	33% 13% 4 7% 6% 2 3 3 4 4 20%	2013
March	1st to 10th	Night	30% 14% 4 7% 5% 3 4 3 4 5% 20%	2053
	11th to 20th	Night	33% 10% 3 7% 7% 3 4 4 4 5% 21%	1980
	21st to end	Night	36% 14% 4 6% 7% 3 4 4 4 5% 16%	2178
April	1st to 10th	Night	32% 14% 4 7% 6% 3 4 3 4 5% 20%	1810
	11th to 20th	Night	27% 13% 4 7% 6% 3 5% 5% 5% 5% 22%	1728
	21st to end	Night	27% 12% 3 7% 4 3 4 4 5% 6% 24%	1620
May	1st to 10th	Night	21% 12% 3 6% 5% 2 4 4 4 6% 32%	1576
	11th to 20th	Night	26% 11% 4 6% 4 3 4 4 5% 8% 25%	1416
	21st to end	Night	25% 11% 3 6% 5% 3 4 5% 4 8% 25%	1552
June	1st to 10th	Night	22% 8% 4 7% 6% 3 5% 4 5% 6% 29%	1440
	11th to 20th	Night	20% 11% 4 7% 5% 2 4 4 5% 8% 30%	1387
	21st to end	Night	15% 11% 3 5% 4 2 3 3 4 7% 43%	1260
July	1st to 10th	Night	9% 10% 4 7% 4 3 3 4 5% 6% 46%	1335
	11th to 20th	Night	12% 8% 2 4 4 1 3 4 4 8% 52%	1440
	21st to end	Night	6% 9% 3 6% 4 2 3 3 4 7% 54%	1672
August	1st to 10th	Night	8% 13% 3 6% 4 2 3 4 4 9% 44%	1611
	11th to 20th	Night	8% 10% 3 5% 4 1 3 2 4 6% 55%	1602
	21st to end	Night	11% 9% 2 5% 4 1 3 3 5% 9% 49%	1864
September	1st to 10th	Night	11% 6% 1 3 3 2 3 4 4 6% 57%	1800
	11th to 20th	Night	14% 9% 3 6% 5% 3 4 4 4 5% 44%	1875
	21st to end	Night	16% 7% 2 4 3 2 4 5% 4 8% 44%	2019
October	1st to 10th	Night	19% 9% 3 6% 4 2 4 4 4 5% 41%	2160
	11th to 20th	Night	22% 6% 3 5% 4 3 3 4 4 8% 37%	2160
	21st to end	Night	26% 8% 3 6% 4 3 4 4 4 5% 33%	2376
November	1st to 10th	Night	33% 8% 3 6% 6% 3 4 4 4 5% 22%	2503
	11th to 20th	Night	37% 8% 3 6% 5% 3 5% 4 4 4 21%	2660
	21st to end	Night	28% 10% 3 6% 5% 3 5% 4 4 5% 27%	2660
December	1st to 10th	Night	29% 11% 3 7% 5% 3 5% 4 5% 5% 25%	2660
	11th to 20th	Night	35% 11% 4 6% 4 3 4 4 5% 6% 20%	3276
	21st to end	Night	34% 15% 4 7% 6% 3 3 3 3 4 18%	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	63% 26% 7% 3 1	2539
	11th to 20th	Day	56% 25% 6% 8% 3 3	2636
	21st to end	Day	60% 25% 5% 5% 5% 1	3146
February	1st to 10th	Day	46% 36% 6% 8% 4 1	1710
	11th to 20th	Day	43% 38% 8% 6% 4 1	1674
	21st to end	Day	49% 35% 6% 7% 3 1	1441
March	1st to 10th	Day	48% 38% 8% 6% 1	2022
	11th to 20th	Day	48% 36% 6% 7% 3	1980
	21st to end	Day	51% 38% 6% 4 1	2178
April	1st to 10th	Day	47% 37% 6% 7% 2	2150
	11th to 20th	Day	44% 36% 7% 7% 4 2	2178
	21st to end	Day	40% 40% 7% 9% 3 1	2340
May	1st to 10th	Day	38% 38% 9% 11% 3	2383
	11th to 20th	Day	35% 40% 10% 10% 4 1	2480
	21st to end	Day	41% 39% 9% 10% 1	2724
June	1st to 10th	Day	42% 38% 9% 8% 3	2520
	11th to 20th	Day	39% 40% 12% 8% 1	2564
	21st to end	Day	26% 37% 12% 16% 7% 2	2700
July	1st to 10th	Day	21% 39% 10% 14% 14% 3	2550
	11th to 20th	Day	22% 37% 7% 15% 15% 4	2445
	21st to end	Day	16% 38% 8% 20% 15% 3	2496
August	1st to 10th	Day	26% 38% 9% 18% 8% 1	2312
	11th to 20th	Day	22% 36% 8% 19% 13% 2	2298
	21st to end	Day	21% 39% 8% 19% 11% 2	2490
September	1st to 10th	Day	16% 37% 8% 19% 13% 7%	2160
	11th to 20th	Day	25% 38% 10% 15% 9% 3	2084
	21st to end	Day	29% 38% 7% 13% 10% 3	1940
October	1st to 10th	Day	32% 37% 6% 11% 11% 3	1800
	11th to 20th	Day	33% 38% 8% 12% 8% 1	1800
	21st to end	Day	37% 38% 6% 9% 8% 2	1980
November	1st to 10th	Day	44% 41% 4 8% 3	1570
	11th to 20th	Day	40% 42% 7% 5% 4 2	1520
	21st to end	Day	40% 41% 5% 8% 5% 1	1520
December	1st to 10th	Day	38% 40% 8% 7% 7% 1	1520
	11th to 20th	Day	48% 33% 10% 5% 4	1928
	21st to end	Day	60% 25% 8% 4 2	2794
January	1st to 10th	Night	63% 26% 5% 4 1	4406
	11th to 20th	Night	56% 25% 6% 8% 2 3	4323
	21st to end	Night	62% 22% 5% 5% 5% 2	4521
February	1st to 10th	Night	46% 36% 7% 6% 4 1	2470
	11th to 20th	Night	41% 37% 6% 9% 5% 1	2404
	21st to end	Night	49% 35% 6% 6% 4	2013
March	1st to 10th	Night	48% 35% 7% 8% 2	2053
	11th to 20th	Night	46% 37% 7% 6% 4	1980
	21st to end	Night	50% 37% 7% 5% 1	2178
April	1st to 10th	Night	46% 37% 6% 7% 4	1810
	11th to 20th	Night	42% 38% 6% 8% 3 3	1728
	21st to end	Night	42% 38% 6% 9% 5% 1	1620
May	1st to 10th	Night	39% 39% 7% 11% 4 1	1576
	11th to 20th	Night	38% 38% 9% 10% 4 3	1416
	21st to end	Night	42% 39% 8% 9% 2	1552
June	1st to 10th	Night	40% 39% 9% 11% 2	1440
	11th to 20th	Night	39% 38% 11% 10% 2	1387
	21st to end	Night	28% 37% 9% 17% 7% 2	1260
July	1st to 10th	Night	26% 37% 10% 12% 12% 3	1296
	11th to 20th	Night	23% 37% 8% 13% 14% 5%	1392
	21st to end	Night	22% 37% 9% 16% 13% 4	1579
August	1st to 10th	Night	28% 37% 8% 18% 8% 1	1602
	11th to 20th	Night	22% 38% 7% 18% 11% 4	1602
	21st to end	Night	24% 37% 8% 16% 12% 2	1864
September	1st to 10th	Night	18% 38% 6% 17% 13% 7%	1800
	11th to 20th	Night	27% 38% 8% 14% 8% 5%	1875
	21st to end	Night	27% 38% 8% 11% 10% 6%	2019
October	1st to 10th	Night	31% 38% 7% 12% 8% 3	2160
	11th to 20th	Night	29% 38% 9% 13% 9% 2	2160
	21st to end	Night	35% 39% 7% 8% 9% 3	2376
November	1st to 10th	Night	41% 42% 5% 7% 3 1	2503
	11th to 20th	Night	43% 40% 6% 6% 3 2	2660
	21st to end	Night	38% 41% 5% 8% 6% 2	2660
December	1st to 10th	Night	37% 41% 7% 8% 6% 1	2660
	11th to 20th	Night	45% 36% 6% 7% 6%	3276
	21st to end	Night	55% 28% 8% 7% 2	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	51% 14% 16% 12% 6%	180
	11th to 20th	Day	49% 9% 17% 17% 5% 3	237
	21st to end	Day	42% 9% 15% 21% 11% 2	407
February	1st to 10th	Day	44% 9% 17% 21% 9% 1	370
	11th to 20th	Day	39% 12% 19% 21% 7% 1	365
	21st to end	Day	38% 15% 21% 17% 8%	321
March	1st to 10th	Day	40% 15% 20% 19% 6% 1	441
	11th to 20th	Day	34% 13% 21% 19% 9% 2	420
	21st to end	Day	40% 16% 20% 15% 8% 1	462
April	1st to 10th	Day	39% 12% 21% 20% 6% 1	420
	11th to 20th	Day	36% 17% 21% 17% 7% 3	412
	21st to end	Day	29% 15% 28% 20% 7% 1	420
May	1st to 10th	Day	22% 14% 30% 23% 9% 2	423
	11th to 20th	Day	29% 14% 25% 20% 9% 2	448
	21st to end	Day	22% 13% 28% 24% 10% 3	485
June	1st to 10th	Day	28% 11% 23% 27% 9% 3	450
	11th to 20th	Day	22% 14% 32% 22% 8% 1	494
	21st to end	Day	11% 8% 31% 37% 10% 2	630
July	1st to 10th	Day	11% 6% 29% 40% 12% 2	545
	11th to 20th	Day	10% 7% 32% 34% 14% 3	444
	21st to end	Day	5% 6% 28% 42% 15% 4	487
August	1st to 10th	Day	9% 7% 22% 39% 16% 6%	447
	11th to 20th	Day	6% 6% 20% 40% 19% 8%	437
	21st to end	Day	8% 8% 31% 33% 17% 4	495
September	1st to 10th	Day	11% 5% 27% 31% 20% 6%	450
	11th to 20th	Day	15% 7% 26% 28% 18% 5%	450
	21st to end	Day	20% 11% 23% 28% 17% 2	450
October	1st to 10th	Day	22% 10% 22% 26% 16% 4	450
	11th to 20th	Day	28% 7% 17% 23% 20% 6%	450
	21st to end	Day	34% 11% 21% 19% 13% 2	495
November	1st to 10th	Day	33% 13% 21% 19% 12% 2	242
	11th to 20th	Day	39% 8% 18% 21% 12% 2	180
	21st to end	Day	36% 11% 16% 26% 11% 1	180
December	1st to 10th	Day	39% 13% 19% 14% 13% 1	180
	11th to 20th	Day	47% 10% 17% 21% 5% 1	180
	21st to end	Day	45% 14% 17% 17% 6% 1	198
January	1st to 10th	Night	47% 11% 16% 18% 8% 1	760
	11th to 20th	Night	43% 8% 18% 17% 13% 1	760
	21st to end	Night	39% 7% 12% 26% 14% 2	836
February	1st to 10th	Night	40% 7% 15% 26% 11% 1	760
	11th to 20th	Night	36% 10% 15% 24% 14% 1	744
	21st to end	Night	40% 11% 13% 24% 11% 1	628
March	1st to 10th	Night	37% 9% 15% 24% 12% 2	742
	11th to 20th	Night	38% 7% 14% 26% 13% 2	720
	21st to end	Night	42% 8% 14% 21% 12% 2	792
April	1st to 10th	Night	38% 9% 14% 23% 15% 2	720
	11th to 20th	Night	32% 10% 17% 23% 15% 3	660
	21st to end	Night	31% 7% 15% 28% 17% 2	540
May	1st to 10th	Night	25% 8% 15% 33% 15% 4	496
	11th to 20th	Night	31% 6% 10% 26% 24% 3	354
	21st to end	Night	30% 7% 15% 25% 19% 4	389
June	1st to 10th	Night	23% 5% 15% 37% 19% 2	360
	11th to 20th	Night	21% 9% 16% 35% 17% 3	360
	21st to end	Night	19% 6% 14% 34% 25% 2	360
July	1st to 10th	Night	14% 5% 12% 36% 29% 3	350
	11th to 20th	Night	14% 5% 17% 41% 19% 3	348
	21st to end	Night	9% 6% 13% 41% 26% 5%	490
August	1st to 10th	Night	14% 5% 9% 32% 33% 7%	537
	11th to 20th	Night	11% 5% 9% 27% 39% 9%	534
	21st to end	Night	14% 7% 10% 36% 27% 6%	676
September	1st to 10th	Night	12% 4 13% 30% 36% 5%	720
	11th to 20th	Night	16% 4 11% 26% 32% 11%	720
	21st to end	Night	19% 5% 13% 30% 28% 6%	720
October	1st to 10th	Night	22% 6% 15% 25% 28% 6%	720
	11th to 20th	Night	26% 4 10% 27% 25% 8%	720
	21st to end	Night	30% 5% 18% 24% 19% 5%	792
November	1st to 10th	Night	35% 7% 14% 26% 16% 2	740
	11th to 20th	Night	40% 9% 15% 21% 14% 1	760
	21st to end	Night	33% 7% 16% 29% 13% 2	760
December	1st to 10th	Night	34% 9% 18% 23% 15% 2	760
	11th to 20th	Night	44% 7% 16% 23% 9%	760
	21st to end	Night	46% 12% 17% 19% 6%	836

Page generated at 2024-03-03 03:28:53. Version ac07

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