McMinnville
Clear Sky Chart
History

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

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	13% 8% 3 7% 5% 5% 5% 4 6% 7% 38%	100878
	Night	13% 8% 3 6% 4 4 4 4 5% 7% 41%	98102
Transparency	Day	41% 8% 11% 20% 15% 3	104632
	Night	39% 7% 11% 21% 17% 4	102460
Seeing	Day	16% 13% 23% 23% 17% 9%	14613
	Night	16% 10% 23% 29% 19% 3	24614

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% 13% 6% 11% 5% 4 4 4 5% 5% 28%	2836
	11th to 20th	Day	19% 13% 5% 11% 4 4 4 2 4 4 30%	2840
	21st to end	Day	24% 12% 7% 5% 4 3 3 3 4 5% 30%	3325
February	1st to 10th	Day	20% 12% 4 9% 4 4 3 2 4 4 34%	1900
	11th to 20th	Day	19% 12% 4 8% 5% 3 4 3 5% 4 32%	1848
	21st to end	Day	19% 11% 4 7% 5% 4 4 3 5% 5% 33%	1570
March	1st to 10th	Day	21% 11% 3 6% 4 4 4 3 5% 6% 32%	3120
	11th to 20th	Day	14% 8% 3 6% 4 4 3 3 4 5% 46%	3415
	21st to end	Day	15% 9% 2 6% 4 5% 4 4 5% 6% 38%	3872
April	1st to 10th	Day	12% 7% 2 6% 5% 4 4 4 6% 7% 42%	2280
	11th to 20th	Day	13% 9% 2 6% 4 4 4 4 5% 6% 44%	2254
	21st to end	Day	13% 7% 3 6% 5% 4 4 4 6% 7% 40%	2372
May	1st to 10th	Day	15% 8% 3 6% 5% 5% 5% 4 7% 8% 35%	4082
	11th to 20th	Day	16% 10% 3 7% 5% 5% 5% 4 5% 6% 33%	4081
	21st to end	Day	11% 6% 2 7% 5% 6% 5% 4 6% 8% 40%	4476
June	1st to 10th	Day	9% 6% 3 8% 5% 5% 6% 5% 6% 8% 39%	2470
	11th to 20th	Day	5% 4 2 6% 6% 5% 6% 5% 7% 10% 44%	2470
	21st to end	Day	6% 5% 2 6% 6% 5% 6% 6% 9% 12% 37%	2470
July	1st to 10th	Day	6% 5% 2 7% 6% 6% 7% 6% 9% 12% 33%	4120
	11th to 20th	Day	10% 6% 2 7% 6% 6% 6% 5% 8% 10% 35%	4120
	21st to end	Day	15% 11% 4 10% 8% 6% 7% 5% 6% 7% 20%	4466
August	1st to 10th	Day	6% 4 2 5% 5% 6% 5% 5% 8% 11% 44%	4026
	11th to 20th	Day	7% 5% 2 7% 6% 6% 6% 5% 8% 11% 38%	3729
	21st to end	Day	7% 4 1 7% 6% 5% 5% 5% 6% 8% 45%	4180
September	1st to 10th	Day	12% 6% 2 8% 6% 4 5% 4 6% 8% 38%	2196
	11th to 20th	Day	13% 7% 2 8% 5% 4 5% 4 5% 7% 40%	2090
	21st to end	Day	12% 5% 2 6% 4 5% 5% 4 4 8% 45%	2090
October	1st to 10th	Day	10% 5% 2 4 4 3 4 4 4 6% 54%	2090
	11th to 20th	Day	13% 5% 1 4 3 3 3 2 5% 7% 53%	2051
	21st to end	Day	15% 6% 2 4 5% 3 3 4 5% 7% 47%	1933
November	1st to 10th	Day	11% 5% 2 4 3 3 3 3 5% 5% 56%	1699
	11th to 20th	Day	12% 8% 3 5% 4 3 3 4 4 6% 47%	1710
	21st to end	Day	15% 7% 2 6% 4 4 3 4 5% 7% 43%	1710
December	1st to 10th	Day	19% 11% 3 8% 5% 5% 4 3 5% 5% 32%	1710
	11th to 20th	Day	15% 12% 3 9% 5% 5% 5% 3 5% 5% 34%	2153
	21st to end	Day	15% 13% 6% 8% 5% 4 5% 4 5% 7% 29%	3124
January	1st to 10th	Night	18% 14% 4 8% 4 3 3 2 4 5% 35%	4109
	11th to 20th	Night	19% 12% 4 8% 5% 5% 3 3 3 4 34%	4120
	21st to end	Night	20% 15% 4 7% 4 4 3 3 3 4 34%	4329
February	1st to 10th	Night	19% 10% 4 8% 4 4 4 3 4 6% 34%	2280
	11th to 20th	Night	23% 10% 3 7% 6% 4 3 3 4 4 33%	2218
	21st to end	Night	22% 11% 3 6% 4 4 4 4 5% 6% 31%	1884
March	1st to 10th	Night	23% 12% 3 5% 5% 4 4 3 4 5% 31%	3733
	11th to 20th	Night	14% 7% 2 5% 4 3 4 3 5% 6% 47%	3544
	21st to end	Night	15% 8% 3 8% 5% 5% 4 3 5% 5% 39%	3786
April	1st to 10th	Night	12% 6% 2 5% 5% 4 5% 3 5% 7% 46%	1900
	11th to 20th	Night	15% 6% 2 5% 3 3 3 3 5% 7% 49%	1875
	21st to end	Night	14% 5% 2 5% 4 3 4 4 6% 8% 44%	1805
May	1st to 10th	Night	11% 7% 2 7% 4 5% 5% 4 5% 8% 40%	2813
	11th to 20th	Night	14% 8% 3 8% 5% 4 4 3 5% 7% 38%	2812
	21st to end	Night	7% 5% 2 7% 5% 5% 5% 4 6% 11% 42%	3079
June	1st to 10th	Night	6% 7% 3 8% 5% 4 5% 5% 6% 9% 43%	1710
	11th to 20th	Night	3 3 2 4 4 4 4 5% 7% 12% 53%	1710
	21st to end	Night	5% 6% 2 6% 4 5% 5% 5% 8% 10% 45%	1710
July	1st to 10th	Night	8% 5% 2 7% 4 6% 5% 6% 9% 12% 36%	2840
	11th to 20th	Night	8% 5% 2 5% 5% 4 5% 4 7% 11% 43%	2840
	21st to end	Night	11% 10% 4 11% 7% 6% 7% 5% 7% 9% 24%	3087
August	1st to 10th	Night	4 4 1 5% 4 5% 5% 4 7% 11% 50%	2885
	11th to 20th	Night	6% 5% 2 5% 4 5% 5% 5% 7% 10% 46%	3100
	21st to end	Night	5% 4 2 4 4 4 5% 3 6% 9% 55%	3476
September	1st to 10th	Night	10% 6% 2 7% 3 5% 5% 4 6% 7% 46%	1963
	11th to 20th	Night	10% 6% 2 6% 5% 4 4 4 5% 8% 45%	2090
	21st to end	Night	9% 5% 2 6% 3 4 3 3 6% 6% 51%	2090
October	1st to 10th	Night	10% 4 2 5% 3 2 4 2 4 6% 59%	2090
	11th to 20th	Night	15% 5% 2 5% 3 4 3 2 4 5% 52%	2128
	21st to end	Night	14% 7% 2 5% 3 3 3 3 4 6% 50%	2660
November	1st to 10th	Night	12% 7% 2 5% 3 3 3 3 5% 5% 53%	2452
	11th to 20th	Night	12% 8% 1 5% 4 3 3 3 6% 6% 48%	2470
	21st to end	Night	15% 8% 3 6% 3 4 3 4 5% 6% 43%	2470
December	1st to 10th	Night	19% 12% 3 7% 4 5% 4 3 5% 5% 32%	2470
	11th to 20th	Night	15% 11% 4 7% 4 3 3 3 4 5% 39%	3042
	21st to end	Night	14% 14% 4 9% 6% 6% 5% 4 5% 6% 26%	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	54% 8% 7% 15% 14% 2	2837
	11th to 20th	Day	56% 7% 5% 13% 18% 2	2840
	21st to end	Day	55% 5% 8% 20% 12% 1	3325
February	1st to 10th	Day	55% 3 7% 15% 17% 2	1900
	11th to 20th	Day	55% 4 6% 17% 14% 4	1858
	21st to end	Day	52% 5% 8% 13% 16% 5%	1570
March	1st to 10th	Day	51% 8% 8% 13% 13% 7%	3120
	11th to 20th	Day	40% 5% 9% 23% 17% 6%	3415
	21st to end	Day	44% 8% 11% 23% 14% 1	3872
April	1st to 10th	Day	39% 8% 11% 21% 17% 3	2280
	11th to 20th	Day	41% 6% 8% 18% 24% 4	2254
	21st to end	Day	41% 7% 10% 26% 14% 1	2372
May	1st to 10th	Day	43% 11% 12% 22% 11% 2	4120
	11th to 20th	Day	47% 10% 12% 22% 9%	4085
	21st to end	Day	39% 11% 11% 21% 17% 1	4489
June	1st to 10th	Day	40% 11% 14% 21% 13% 1	2470
	11th to 20th	Day	31% 11% 19% 21% 16% 2	2470
	21st to end	Day	35% 13% 18% 17% 13% 3	2470
July	1st to 10th	Day	37% 12% 23% 20% 7% 1	4055
	11th to 20th	Day	40% 11% 19% 23% 6% 2	4051
	21st to end	Day	59% 11% 11% 14% 5%	4324
August	1st to 10th	Day	29% 12% 17% 29% 12% 1	4013
	11th to 20th	Day	35% 10% 17% 24% 13% 1	3765
	21st to end	Day	32% 11% 12% 27% 16% 1	4179
September	1st to 10th	Day	41% 11% 12% 16% 15% 5%	2196
	11th to 20th	Day	41% 9% 11% 19% 17% 2	2090
	21st to end	Day	38% 7% 12% 21% 18% 5%	2090
October	1st to 10th	Day	23% 6% 7% 17% 35% 11%	3480
	11th to 20th	Day	22% 4 7% 23% 29% 15%	3382
	21st to end	Day	26% 5% 10% 23% 26% 10%	3157
November	1st to 10th	Day	30% 5% 9% 22% 28% 6%	1699
	11th to 20th	Day	38% 5% 6% 22% 23% 7%	1710
	21st to end	Day	41% 6% 7% 21% 22% 4	1710
December	1st to 10th	Day	53% 5% 6% 19% 13% 3	1710
	11th to 20th	Day	51% 6% 8% 15% 17% 2	2150
	21st to end	Day	51% 6% 12% 18% 11% 2	3124
January	1st to 10th	Night	50% 7% 8% 17% 17% 2	4109
	11th to 20th	Night	54% 5% 7% 12% 16% 6%	4120
	21st to end	Night	55% 4 6% 14% 18% 2	4329
February	1st to 10th	Night	51% 5% 9% 16% 16% 2	2280
	11th to 20th	Night	55% 5% 6% 15% 14% 5%	2219
	21st to end	Night	54% 4 8% 15% 13% 5%	1884
March	1st to 10th	Night	54% 8% 9% 10% 15% 5%	3733
	11th to 20th	Night	37% 7% 8% 23% 16% 10%	3544
	21st to end	Night	46% 7% 9% 21% 16% 1	3786
April	1st to 10th	Night	36% 8% 10% 23% 20% 3	1900
	11th to 20th	Night	36% 5% 9% 21% 22% 7%	1875
	21st to end	Night	37% 8% 12% 27% 15% 1	1805
May	1st to 10th	Night	39% 11% 13% 23% 13% 1	2840
	11th to 20th	Night	44% 10% 13% 20% 13% 1	2813
	21st to end	Night	31% 13% 16% 24% 15% 1	3087
June	1st to 10th	Night	37% 9% 15% 24% 13% 2	1710
	11th to 20th	Night	21% 9% 21% 31% 15% 2	1710
	21st to end	Night	31% 10% 17% 25% 12% 5%	1710
July	1st to 10th	Night	35% 13% 21% 22% 8% 1	2795
	11th to 20th	Night	32% 10% 20% 29% 7% 2	2786
	21st to end	Night	53% 11% 13% 15% 6% 1	2988
August	1st to 10th	Night	25% 10% 14% 35% 16% 1	2874
	11th to 20th	Night	29% 11% 23% 23% 13% 1	3130
	21st to end	Night	23% 10% 13% 32% 20% 1	3476
September	1st to 10th	Night	34% 10% 14% 20% 17% 5%	1963
	11th to 20th	Night	36% 8% 12% 20% 21% 2	2090
	21st to end	Night	32% 7% 12% 23% 22% 5%	2090
October	1st to 10th	Night	22% 6% 8% 22% 30% 14%	3480
	11th to 20th	Night	22% 4 5% 22% 28% 17%	3523
	21st to end	Night	24% 4 7% 25% 29% 11%	4373
November	1st to 10th	Night	33% 5% 8% 22% 25% 8%	2452
	11th to 20th	Night	36% 5% 8% 19% 25% 8%	2470
	21st to end	Night	43% 4 6% 21% 21% 5%	2470
December	1st to 10th	Night	53% 5% 9% 17% 14% 3	2470
	11th to 20th	Night	45% 6% 7% 17% 20% 4	3044
	21st to end	Night	52% 9% 10% 16% 11% 1	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	24% 27% 31% 13% 5%	270
	11th to 20th	Day	31% 30% 24% 11% 3 1	270
	21st to end	Day	22% 30% 37% 9% 3	297
February	1st to 10th	Day	27% 27% 30% 13% 3	270
	11th to 20th	Day	36% 26% 29% 6% 2 1	270
	21st to end	Day	34% 30% 28% 7% 1	225
March	1st to 10th	Day	27% 23% 34% 13% 3	270
	11th to 20th	Day	24% 25% 29% 16% 5% 1	421
	21st to end	Day	24% 19% 34% 16% 7% 1	506
April	1st to 10th	Day	19% 22% 25% 22% 11%	460
	11th to 20th	Day	19% 19% 30% 22% 9% 2	452
	21st to end	Day	18% 17% 29% 23% 12% 2	460
May	1st to 10th	Day	15% 16% 30% 24% 11% 5%	463
	11th to 20th	Day	14% 9% 25% 26% 17% 8%	487
	21st to end	Day	12% 7% 22% 28% 19% 13%	529
June	1st to 10th	Day	12% 7% 19% 27% 22% 14%	490
	11th to 20th	Day	5% 3 17% 30% 27% 19%	490
	21st to end	Day	7% 4 20% 28% 24% 17%	490
July	1st to 10th	Day	10% 2 13% 29% 24% 21%	485
	11th to 20th	Day	10% 5% 11% 23% 27% 25%	484
	21st to end	Day	11% 3 11% 26% 27% 22%	532
August	1st to 10th	Day	10% 5% 13% 27% 28% 18%	486
	11th to 20th	Day	9% 4 15% 29% 31% 11%	479
	21st to end	Day	12% 3 9% 23% 32% 20%	539
September	1st to 10th	Day	10% 6% 11% 27% 31% 16%	490
	11th to 20th	Day	14% 5% 14% 25% 28% 14%	490
	21st to end	Day	16% 5% 17% 27% 28% 8%	490
October	1st to 10th	Day	13% 7% 18% 31% 22% 9%	490
	11th to 20th	Day	13% 11% 29% 28% 15% 4	490
	21st to end	Day	20% 11% 29% 26% 11% 3	382
November	1st to 10th	Day	16% 9% 33% 28% 10% 3	279
	11th to 20th	Day	14% 19% 39% 24% 4	270
	21st to end	Day	18% 19% 34% 19% 9% 2	270
December	1st to 10th	Day	29% 20% 29% 17% 5% 1	270
	11th to 20th	Day	24% 21% 28% 18% 8%	270
	21st to end	Day	23% 26% 32% 15% 3	297
January	1st to 10th	Night	23% 19% 31% 22% 4	760
	11th to 20th	Night	26% 22% 29% 19% 4	760
	21st to end	Night	20% 19% 37% 21% 3	836
February	1st to 10th	Night	23% 15% 33% 25% 3	760
	11th to 20th	Night	29% 17% 31% 21% 2	743
	21st to end	Night	29% 21% 30% 19% 1	628
March	1st to 10th	Night	23% 15% 32% 26% 4	760
	11th to 20th	Night	21% 16% 32% 24% 7% 1	760
	21st to end	Night	20% 14% 31% 26% 9%	817
April	1st to 10th	Night	16% 14% 29% 30% 11%	570
	11th to 20th	Night	18% 11% 31% 28% 10% 2	563
	21st to end	Night	15% 9% 29% 34% 12% 1	570
May	1st to 10th	Night	12% 9% 29% 29% 19% 1	570
	11th to 20th	Night	15% 5% 21% 35% 20% 4	561
	21st to end	Night	7% 4 15% 36% 32% 6%	617
June	1st to 10th	Night	7% 5% 15% 36% 32% 5%	570
	11th to 20th	Night	3 2 13% 35% 37% 10%	570
	21st to end	Night	6% 2 12% 37% 35% 8%	570
July	1st to 10th	Night	10% 3 6% 27% 43% 10%	555
	11th to 20th	Night	8% 2 8% 27% 42% 12%	552
	21st to end	Night	8% 2 8% 31% 40% 11%	624
August	1st to 10th	Night	7% 2 5% 29% 47% 10%	567
	11th to 20th	Night	7% 2 9% 36% 40% 6%	564
	21st to end	Night	9% 2 7% 27% 46% 9%	627
September	1st to 10th	Night	12% 3 9% 30% 39% 8%	633
	11th to 20th	Night	12% 3 14% 30% 35% 6%	760
	21st to end	Night	11% 2 16% 34% 33% 4	760
October	1st to 10th	Night	11% 6% 16% 32% 28% 7%	760
	11th to 20th	Night	17% 8% 23% 31% 19% 2	760
	21st to end	Night	17% 10% 24% 33% 15% 3	836
November	1st to 10th	Night	16% 8% 21% 35% 17% 3	755
	11th to 20th	Night	15% 15% 29% 29% 11% 1	760
	21st to end	Night	20% 13% 27% 30% 9% 1	760
December	1st to 10th	Night	26% 14% 28% 26% 6%	760
	11th to 20th	Night	22% 14% 29% 28% 7% 1	760
	21st to end	Night	24% 18% 29% 25% 5%	836

Page generated at 2024-11-01 21:47:45. Version ac07

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