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 2026-09-29.

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	19% 10% 3 7% 4 4 4 3 5% 7% 35%	159199
	Night	23% 13% 4 8% 4 4 4 3 4 5% 30%	149598
Transparency	Day	48% 6% 13% 18% 11% 3	153964
	Night	55% 6% 11% 15% 10% 4	145834
Seeing	Day	25% 11% 25% 25% 11% 3	17563
	Night	30% 8% 15% 27% 18% 3	26040

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	39% 18% 4 9% 5% 4 3 2 2 3 10%	4722
	11th to 20th	Day	23% 7% 2 5% 3 3 3 2 4 6% 42%	4920
	21st to end	Day	30% 9% 3 7% 4 4 4 3 4 4 28%	5843
February	1st to 10th	Day	34% 12% 3 8% 5% 4 4 3 4 6% 16%	1890
	11th to 20th	Day	32% 13% 2 8% 5% 5% 4 4 5% 4 18%	1845
	21st to end	Day	31% 17% 5% 7% 4 3 3 3 4 5% 18%	1588
March	1st to 10th	Day	20% 18% 4 9% 6% 5% 5% 4 6% 6% 17%	5033
	11th to 20th	Day	32% 14% 4 7% 4 3 3 2 3 4 23%	5110
	21st to end	Day	29% 15% 4 11% 6% 5% 5% 4 5% 5% 10%	5607
April	1st to 10th	Day	30% 13% 4 8% 5% 4 5% 4 6% 6% 16%	2509
	11th to 20th	Day	26% 11% 3 8% 6% 4 3 4 4 6% 24%	2544
	21st to end	Day	26% 9% 3 7% 5% 4 5% 4 5% 6% 24%	2730
May	1st to 10th	Day	15% 10% 4 8% 4 4 3 3 5% 8% 36%	7772
	11th to 20th	Day	13% 9% 3 8% 5% 5% 5% 5% 7% 9% 31%	8160
	21st to end	Day	16% 8% 3 6% 4 4 5% 4 7% 9% 34%	8992
June	1st to 10th	Day	26% 9% 3 6% 4 4 3 3 5% 6% 31%	2940
	11th to 20th	Day	20% 8% 3 6% 5% 4 5% 4 6% 8% 31%	2993
	21st to end	Day	14% 7% 2 6% 4 4 3 3 5% 8% 43%	3150
July	1st to 10th	Day	3 5% 2 4 3 3 4 3 5% 8% 60%	8543
	11th to 20th	Day	5% 6% 2 5% 3 2 3 3 4 8% 59%	8220
	21st to end	Day	7% 8% 3 6% 3 3 3 3 5% 7% 51%	8593
August	1st to 10th	Day	6% 7% 2 6% 3 4 3 3 4 8% 54%	7547
	11th to 20th	Day	7% 7% 3 7% 5% 5% 5% 4 6% 10% 40%	7563
	21st to end	Day	6% 9% 3 7% 4 4 5% 4 6% 9% 45%	8094
September	1st to 10th	Day	8% 6% 3 5% 3 3 4 3 5% 8% 53%	2520
	11th to 20th	Day	11% 8% 3 6% 4 4 3 4 6% 9% 42%	2430
	21st to end	Day	18% 6% 2 5% 3 3 4 4 5% 7% 43%	2244
October	1st to 10th	Day	18% 6% 2 5% 3 3 3 3 4 6% 49%	3280
	11th to 20th	Day	22% 10% 4 8% 5% 5% 4 4 5% 7% 27%	3261
	21st to end	Day	29% 9% 3 7% 4 4 4 3 6% 7% 24%	3558
November	1st to 10th	Day	34% 11% 3 8% 4 4 4 3 6% 5% 19%	1738
	11th to 20th	Day	35% 10% 3 6% 5% 3 4 3 5% 5% 20%	1680
	21st to end	Day	31% 10% 3 7% 5% 3 4 3 5% 6% 24%	1680
December	1st to 10th	Day	24% 7% 2 6% 5% 3 3 3 4 5% 37%	2700
	11th to 20th	Day	36% 13% 3 10% 5% 4 4 3 3 4 13%	3108
	21st to end	Day	43% 16% 4 8% 3 3 3 2 3 4 11%	4092
January	1st to 10th	Night	38% 16% 3 9% 5% 4 3 3 3 4 11%	8172
	11th to 20th	Night	22% 9% 2 6% 3 3 3 2 3 5% 42%	8032
	21st to end	Night	33% 11% 3 6% 3 3 2 2 3 4 30%	8371
February	1st to 10th	Night	31% 13% 4 9% 6% 4 4 4 4 5% 17%	2730
	11th to 20th	Night	30% 14% 3 9% 4 3 3 4 4 4 22%	2662
	21st to end	Night	32% 14% 3 8% 5% 3 3 3 4 5% 20%	2218
March	1st to 10th	Night	21% 18% 4 10% 6% 6% 5% 3 4 6% 16%	5067
	11th to 20th	Night	28% 15% 4 9% 5% 4 3 3 3 3 23%	5110
	21st to end	Night	31% 18% 4 10% 6% 5% 4 3 4 4 12%	5610
April	1st to 10th	Night	30% 14% 3 8% 6% 4 3 3 4 5% 20%	2111
	11th to 20th	Night	24% 14% 3 8% 5% 4 4 4 5% 5% 24%	2019
	21st to end	Night	26% 13% 3 7% 4 4 4 3 5% 6% 25%	1890
May	1st to 10th	Night	16% 15% 5% 7% 4 3 3 3 4 6% 34%	5167
	11th to 20th	Night	19% 13% 4 10% 5% 5% 5% 3 5% 6% 26%	4700
	21st to end	Night	18% 12% 3 7% 3 3 4 3 5% 7% 35%	5181
June	1st to 10th	Night	20% 10% 3 7% 5% 5% 3 4 5% 6% 31%	1680
	11th to 20th	Night	18% 11% 3 7% 3 3 4 4 5% 8% 34%	1618
	21st to end	Night	16% 12% 3 6% 3 3 2 3 4 6% 40%	1470
July	1st to 10th	Night	4 12% 3 8% 2 2 2 2 3 5% 56%	4397
	11th to 20th	Night	6% 11% 3 8% 4 3 4 2 3 4 51%	4740
	21st to end	Night	7% 20% 5% 9% 3 3 3 3 3 5% 39%	5484
August	1st to 10th	Night	8% 15% 4 9% 3 3 3 3 3 5% 43%	5275
	11th to 20th	Night	10% 19% 6% 10% 4 4 4 2 4 5% 32%	5292
	21st to end	Night	10% 17% 4 6% 3 2 3 2 4 6% 43%	6135
September	1st to 10th	Night	11% 9% 2 4 3 3 3 3 4 6% 51%	2100
	11th to 20th	Night	13% 10% 3 7% 4 4 4 3 3 4 43%	2188
	21st to end	Night	15% 7% 2 5% 3 3 4 4 4 8% 44%	2332
October	1st to 10th	Night	13% 7% 3 6% 4 3 4 3 5% 6% 47%	3920
	11th to 20th	Night	20% 11% 4 8% 5% 4 4 4 5% 7% 27%	3897
	21st to end	Night	28% 10% 3 8% 4 5% 4 3 4 5% 25%	4253
November	1st to 10th	Night	33% 9% 3 7% 4 4 5% 3 5% 6% 21%	2775
	11th to 20th	Night	38% 8% 3 7% 4 4 4 3 4 4 20%	2940
	21st to end	Night	27% 11% 3 7% 4 4 4 3 4 5% 26%	2940
December	1st to 10th	Night	23% 9% 2 6% 3 3 3 3 5% 5% 38%	4700
	11th to 20th	Night	42% 12% 4 8% 4 3 3 2 4 5% 13%	5316
	21st to end	Night	39% 14% 3 8% 5% 4 3 2 3 4 14%	7106

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	80% 4 5% 7% 4 1	4723
	11th to 20th	Day	45% 3 7% 17% 16% 12%	4920
	21st to end	Day	60% 4 6% 11% 14% 6%	5843
February	1st to 10th	Day	70% 5% 9% 10% 4 1	1890
	11th to 20th	Day	69% 6% 9% 8% 6% 2	1854
	21st to end	Day	70% 4 9% 10% 6% 2	1588
March	1st to 10th	Day	64% 6% 16% 10% 4	5033
	11th to 20th	Day	65% 7% 7% 13% 8% 1	5110
	21st to end	Day	74% 6% 11% 5% 3	5607
April	1st to 10th	Day	68% 6% 12% 10% 3	2509
	11th to 20th	Day	61% 6% 11% 13% 6% 2	2547
	21st to end	Day	59% 8% 11% 16% 5% 1	2730
May	1st to 10th	Day	44% 7% 13% 25% 10%	7772
	11th to 20th	Day	43% 10% 22% 20% 5%	8163
	21st to end	Day	43% 9% 25% 20% 2	8994
June	1st to 10th	Day	54% 6% 15% 18% 7%	2940
	11th to 20th	Day	49% 9% 17% 20% 5% 1	2993
	21st to end	Day	39% 7% 19% 23% 9% 2	3150
July	1st to 10th	Day	19% 5% 16% 28% 19% 14%	8474
	11th to 20th	Day	23% 4 9% 19% 37% 8%	8145
	21st to end	Day	29% 5% 16% 32% 17% 2	8401
August	1st to 10th	Day	25% 5% 9% 26% 24% 11%	5976
	11th to 20th	Day	34% 6% 21% 29% 9% 1	5962
	21st to end	Day	32% 7% 18% 27% 14% 3	6349
September	1st to 10th	Day	29% 6% 13% 27% 16% 9%	2520
	11th to 20th	Day	39% 7% 16% 19% 14% 5%	2430
	21st to end	Day	41% 6% 14% 21% 14% 4	2244
October	1st to 10th	Day	38% 4 7% 25% 24% 3	3280
	11th to 20th	Day	56% 5% 13% 14% 10% 1	3261
	21st to end	Day	59% 5% 10% 16% 9% 2	3558
November	1st to 10th	Day	67% 5% 9% 14% 5%	1738
	11th to 20th	Day	66% 7% 9% 8% 6% 3	1680
	21st to end	Day	62% 5% 9% 11% 9% 4	1680
December	1st to 10th	Day	50% 4 8% 15% 21% 1	2700
	11th to 20th	Day	76% 5% 9% 6% 3	3108
	21st to end	Day	78% 5% 9% 5% 2 1	4092
January	1st to 10th	Night	78% 4 7% 7% 3 1	8172
	11th to 20th	Night	46% 4 7% 16% 16% 11%	8032
	21st to end	Night	61% 2 5% 8% 17% 7%	8371
February	1st to 10th	Night	69% 6% 9% 10% 4 2	2730
	11th to 20th	Night	66% 5% 9% 10% 7% 2	2664
	21st to end	Night	67% 5% 9% 10% 7% 2	2218
March	1st to 10th	Night	68% 6% 10% 12% 4	5067
	11th to 20th	Night	65% 6% 8% 11% 9% 1	5110
	21st to end	Night	74% 7% 11% 7% 2	5610
April	1st to 10th	Night	67% 6% 11% 11% 4	2111
	11th to 20th	Night	60% 7% 10% 14% 6% 3	2019
	21st to end	Night	59% 8% 10% 16% 6% 2	1890
May	1st to 10th	Night	47% 8% 12% 25% 7% 1	5165
	11th to 20th	Night	52% 11% 13% 17% 6% 1	4700
	21st to end	Night	44% 9% 27% 18% 2	5182
June	1st to 10th	Night	51% 9% 13% 22% 5%	1680
	11th to 20th	Night	46% 9% 15% 23% 7% 1	1618
	21st to end	Night	42% 8% 15% 25% 7% 3	1470
July	1st to 10th	Night	24% 5% 16% 20% 20% 15%	4358
	11th to 20th	Night	29% 4 10% 16% 30% 11%	4692
	21st to end	Night	39% 6% 16% 21% 15% 4	5364
August	1st to 10th	Night	34% 6% 8% 20% 19% 14%	4169
	11th to 20th	Night	45% 6% 18% 21% 8% 2	4169
	21st to end	Night	36% 7% 16% 23% 15% 3	4806
September	1st to 10th	Night	32% 6% 12% 24% 17% 9%	2100
	11th to 20th	Night	42% 8% 12% 19% 13% 6%	2188
	21st to end	Night	36% 7% 14% 20% 16% 7%	2332
October	1st to 10th	Night	36% 6% 9% 26% 20% 3	3920
	11th to 20th	Night	56% 5% 14% 14% 9% 2	3897
	21st to end	Night	61% 5% 9% 15% 8% 2	4253
November	1st to 10th	Night	65% 6% 9% 12% 7% 1	2775
	11th to 20th	Night	68% 5% 8% 8% 6% 3	2940
	21st to end	Night	60% 5% 8% 11% 10% 6%	2940
December	1st to 10th	Night	49% 4 8% 16% 20% 3	4700
	11th to 20th	Night	76% 5% 7% 7% 4 1	5316
	21st to end	Night	74% 7% 9% 8% 2 1	7106

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	50% 13% 21% 11% 5%	220
	11th to 20th	Day	41% 7% 20% 21% 8% 2	283
	21st to end	Day	39% 8% 18% 22% 11% 2	473
February	1st to 10th	Day	42% 9% 19% 20% 8% 1	430
	11th to 20th	Day	40% 13% 19% 20% 7% 1	425
	21st to end	Day	39% 14% 22% 17% 8%	372
March	1st to 10th	Day	41% 15% 19% 19% 6% 1	540
	11th to 20th	Day	36% 13% 20% 19% 8% 3	540
	21st to end	Day	37% 17% 22% 15% 8% 1	594
April	1st to 10th	Day	36% 11% 22% 21% 8% 2	540
	11th to 20th	Day	32% 17% 24% 17% 8% 2	532
	21st to end	Day	28% 16% 27% 21% 6% 2	540
May	1st to 10th	Day	21% 15% 29% 22% 10% 3	543
	11th to 20th	Day	27% 16% 26% 20% 9% 2	568
	21st to end	Day	21% 13% 29% 25% 9% 3	617
June	1st to 10th	Day	26% 13% 24% 24% 10% 3	570
	11th to 20th	Day	20% 14% 33% 22% 9% 2	623
	21st to end	Day	12% 8% 33% 34% 10% 3	780
July	1st to 10th	Day	9% 6% 32% 37% 13% 3	681
	11th to 20th	Day	10% 7% 34% 32% 15% 3	564
	21st to end	Day	6% 7% 28% 39% 15% 5%	619
August	1st to 10th	Day	9% 8% 25% 36% 17% 6%	567
	11th to 20th	Day	8% 7% 22% 38% 18% 8%	557
	21st to end	Day	9% 9% 30% 31% 17% 6%	627
September	1st to 10th	Day	13% 6% 25% 29% 20% 6%	570
	11th to 20th	Day	15% 8% 28% 27% 16% 6%	570
	21st to end	Day	19% 10% 24% 26% 18% 3	563
October	1st to 10th	Day	22% 10% 22% 26% 17% 4	530
	11th to 20th	Day	27% 9% 18% 24% 17% 5%	530
	21st to end	Day	34% 10% 22% 19% 12% 2	583
November	1st to 10th	Day	36% 13% 21% 18% 11% 2	290
	11th to 20th	Day	41% 10% 18% 19% 10% 1	220
	21st to end	Day	36% 9% 18% 25% 10% 1	220
December	1st to 10th	Day	40% 12% 20% 15% 12% 1	220
	11th to 20th	Day	48% 10% 19% 18% 4	220
	21st to end	Day	46% 13% 18% 17% 5%	242
January	1st to 10th	Night	46% 12% 18% 17% 7% 1	840
	11th to 20th	Night	39% 7% 20% 21% 13% 1	840
	21st to end	Night	37% 7% 14% 25% 14% 2	924
February	1st to 10th	Night	39% 8% 17% 26% 10% 1	840
	11th to 20th	Night	36% 10% 16% 24% 13% 1	824
	21st to end	Night	40% 11% 13% 25% 10% 1	692
March	1st to 10th	Night	36% 10% 16% 24% 11% 2	840
	11th to 20th	Night	38% 7% 15% 25% 12% 3	840
	21st to end	Night	41% 9% 15% 22% 11% 2	924
April	1st to 10th	Night	35% 9% 14% 25% 16% 1	840
	11th to 20th	Night	30% 10% 19% 23% 15% 2	771
	21st to end	Night	31% 8% 14% 29% 17% 2	630
May	1st to 10th	Night	25% 7% 16% 33% 16% 4	578
	11th to 20th	Night	29% 7% 14% 26% 22% 3	414
	21st to end	Night	28% 8% 15% 26% 19% 3	455
June	1st to 10th	Night	23% 5% 16% 35% 18% 2	420
	11th to 20th	Night	19% 8% 18% 37% 15% 3	420
	21st to end	Night	21% 6% 13% 33% 25% 2	420
July	1st to 10th	Night	14% 5% 14% 37% 28% 3	410
	11th to 20th	Night	13% 5% 18% 42% 18% 3	408
	21st to end	Night	10% 6% 13% 39% 26% 5%	573
August	1st to 10th	Night	14% 5% 10% 32% 32% 7%	627
	11th to 20th	Night	13% 6% 9% 28% 36% 8%	624
	21st to end	Night	14% 7% 10% 35% 27% 6%	790
September	1st to 10th	Night	14% 6% 13% 29% 34% 5%	840
	11th to 20th	Night	16% 5% 12% 28% 29% 10%	840
	21st to end	Night	19% 5% 13% 31% 27% 6%	832
October	1st to 10th	Night	22% 6% 15% 27% 27% 5%	800
	11th to 20th	Night	26% 4 10% 29% 24% 7%	800
	21st to end	Night	30% 5% 18% 25% 17% 5%	880
November	1st to 10th	Night	36% 7% 15% 26% 15% 2	820
	11th to 20th	Night	42% 8% 15% 21% 13% 1	840
	21st to end	Night	33% 8% 16% 29% 13% 2	840
December	1st to 10th	Night	34% 9% 18% 24% 14% 1	840
	11th to 20th	Night	45% 8% 16% 22% 9%	840
	21st to end	Night	46% 12% 18% 19% 6%	924

Page generated at 2026-09-26 01:18:40. Version ac07

Copyright © 2026 Attilla Danko.