Ucluelet
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ucluelet clear sky chart from 2005-11-06 to 2024-02-05.

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	29% 9% 3 6% 5% 3 4 4 4 6% 25%	77729
	Night	34% 10% 3 6% 5% 3 3 3 4 5% 25%	81085
Transparency	Day	60% 8% 12% 13% 6% 1	77432
	Night	63% 6% 10% 13% 6% 1	80963
Seeing	Day	29% 5% 13% 24% 22% 8%	14687
	Night	36% 5% 12% 21% 18% 8%	22872

By Month

Percentage Cloud Cover NW (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	44% 12% 3 5% 4 2 3 3 4 4 16%	2219
	11th to 20th	Day	35% 10% 3 6% 5% 4 3 4 4 5% 20%	2199
	21st to end	Day	57% 9% 3 6% 4 2 2 2 2 2 11%	2765
February	1st to 10th	Day	41% 11% 3 5% 4 3 4 4 4 5% 16%	1657
	11th to 20th	Day	36% 9% 3 6% 5% 2 3 3 3 4 25%	1575
	21st to end	Day	31% 9% 5% 8% 5% 3 3 3 3 6% 25%	1332
March	1st to 10th	Day	34% 11% 3 6% 5% 3 4 4 4 5% 21%	1904
	11th to 20th	Day	39% 9% 4 6% 4 3 4 3 4 3 20%	1980
	21st to end	Day	37% 12% 4 5% 5% 3 3 3 3 4 22%	2178
April	1st to 10th	Day	34% 11% 4 6% 5% 2 4 4 4 6% 21%	2154
	11th to 20th	Day	29% 10% 3 6% 5% 3 3 5% 4 6% 24%	2308
	21st to end	Day	31% 9% 3 6% 5% 3 4 3 4 6% 26%	2340
May	1st to 10th	Day	24% 8% 3 6% 6% 3 5% 5% 5% 7% 29%	2456
	11th to 20th	Day	24% 10% 4 7% 6% 4 4 4 5% 8% 23%	2477
	21st to end	Day	20% 9% 4 8% 6% 4 4 5% 6% 8% 25%	2910
June	1st to 10th	Day	27% 10% 4 6% 5% 3 5% 4 5% 6% 24%	2700
	11th to 20th	Day	20% 11% 4 7% 7% 4 6% 6% 5% 7% 22%	2700
	21st to end	Day	22% 9% 4 5% 4 3 6% 4 5% 7% 29%	2700
July	1st to 10th	Day	19% 9% 4 7% 5% 3 4 4 5% 6% 33%	2700
	11th to 20th	Day	14% 10% 3 6% 5% 3 4 5% 5% 8% 37%	2700
	21st to end	Day	12% 8% 4 6% 5% 3 6% 6% 6% 9% 36%	2920
August	1st to 10th	Day	15% 10% 4 7% 6% 4 6% 6% 6% 9% 29%	2343
	11th to 20th	Day	12% 10% 3 7% 4 3 5% 5% 5% 9% 37%	2298
	21st to end	Day	17% 9% 3 6% 5% 3 4 5% 6% 9% 32%	2574
September	1st to 10th	Day	17% 9% 3 6% 6% 3 4 5% 4 8% 35%	2191
	11th to 20th	Day	24% 9% 3 6% 5% 3 5% 5% 5% 5% 31%	2030
	21st to end	Day	26% 7% 3 5% 4 2 4 3 4 5% 37%	1980
October	1st to 10th	Day	27% 7% 3 6% 5% 3 4 4 6% 6% 29%	1800
	11th to 20th	Day	33% 9% 4 4 6% 3 5% 4 7% 6% 19%	1800
	21st to end	Day	36% 8% 2 5% 4 2 3 4 4 5% 27%	1834
November	1st to 10th	Day	42% 8% 2 6% 5% 2 3 5% 5% 3 18%	1488
	11th to 20th	Day	42% 9% 3 6% 4 2 3 3 3 4 22%	1520
	21st to end	Day	41% 7% 3 4 4 3 4 3 3 5% 23%	1520
December	1st to 10th	Day	32% 10% 3 6% 5% 3 3 4 2 5% 27%	1350
	11th to 20th	Day	44% 11% 3 6% 4 2 3 4 3 3 17%	1685
	21st to end	Day	51% 9% 3 5% 5% 2 2 3 3 4 12%	2442
January	1st to 10th	Night	42% 14% 3 7% 4 2 3 3 3 3 15%	4726
	11th to 20th	Night	37% 9% 3 5% 4 2 3 3 4 6% 25%	4699
	21st to end	Night	60% 9% 3 4 3 2 2 2 2 2 10%	4894
February	1st to 10th	Night	41% 12% 3 5% 4 2 3 3 4 5% 18%	2397
	11th to 20th	Night	32% 11% 3 5% 4 3 4 2 4 5% 27%	2272
	21st to end	Night	34% 12% 3 6% 5% 2 3 3 4 4 24%	1924
March	1st to 10th	Night	34% 11% 3 6% 6% 4 4 4 3 4 21%	2053
	11th to 20th	Night	38% 12% 3 7% 5% 2 3 3 4 4 19%	1979
	21st to end	Night	36% 14% 4 7% 5% 3 3 3 3 4 19%	2178
April	1st to 10th	Night	34% 11% 3 6% 5% 3 3 4 4 4 23%	1803
	11th to 20th	Night	30% 13% 3 5% 6% 2 3 4 4 6% 24%	1601
	21st to end	Night	30% 10% 3 7% 5% 3 5% 3 3 4 27%	1620
May	1st to 10th	Night	21% 9% 4 6% 5% 3 4 3 5% 6% 35%	1504
	11th to 20th	Night	23% 10% 3 8% 6% 3 6% 5% 4 7% 26%	1416
	21st to end	Night	23% 9% 4 6% 5% 2 4 3 5% 7% 33%	1362
June	1st to 10th	Night	26% 11% 3 7% 5% 3 5% 4 4 5% 28%	1260
	11th to 20th	Night	24% 9% 4 7% 5% 4 5% 4 5% 5% 27%	1260
	21st to end	Night	19% 11% 4 7% 5% 2 4 5% 5% 7% 30%	1260
July	1st to 10th	Night	17% 9% 3 4 5% 2 4 4 6% 7% 38%	1260
	11th to 20th	Night	11% 8% 2 5% 4 3 4 4 6% 9% 45%	1260
	21st to end	Night	10% 9% 2 6% 5% 3 5% 5% 5% 6% 44%	1396
August	1st to 10th	Night	13% 13% 3 7% 5% 3 5% 4 5% 7% 36%	1593
	11th to 20th	Night	10% 8% 2 5% 5% 3 4 4 5% 7% 48%	1602
	21st to end	Night	17% 10% 3 5% 4 3 4 4 4 7% 38%	1782
September	1st to 10th	Night	13% 9% 2 5% 5% 3 3 3 5% 6% 46%	1768
	11th to 20th	Night	23% 10% 3 5% 5% 3 3 4 4 6% 34%	1929
	21st to end	Night	27% 7% 2 4 3 2 4 3 4 6% 37%	1980
October	1st to 10th	Night	26% 8% 3 6% 4 3 3 4 4 4 35%	2160
	11th to 20th	Night	34% 9% 3 6% 5% 3 4 3 4 5% 26%	2160
	21st to end	Night	36% 7% 3 5% 5% 2 3 3 3 4 29%	2517
November	1st to 10th	Night	42% 9% 3 6% 5% 3 4 3 3 4 18%	2590
	11th to 20th	Night	37% 10% 3 7% 6% 3 4 4 3 3 20%	2660
	21st to end	Night	41% 8% 3 5% 4 3 3 3 3 4 23%	2660
December	1st to 10th	Night	32% 11% 4 5% 5% 3 4 4 4 4 24%	2826
	11th to 20th	Night	46% 11% 3 6% 4 2 3 3 3 4 15%	3520
	21st to end	Night	48% 11% 3 6% 4 2 3 3 3 3 14%	5214

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	72% 5% 8% 10% 5% 1	2219
	11th to 20th	Day	63% 8% 8% 14% 5% 1	2220
	21st to end	Day	83% 3 4 8% 2	2765
February	1st to 10th	Day	71% 7% 7% 9% 5% 1	1657
	11th to 20th	Day	65% 4 8% 13% 8% 1	1584
	21st to end	Day	62% 4 8% 15% 8% 2	1332
March	1st to 10th	Day	65% 5% 12% 12% 5%	1904
	11th to 20th	Day	69% 5% 10% 10% 4 2	1980
	21st to end	Day	68% 5% 11% 13% 3	2178
April	1st to 10th	Day	65% 7% 11% 12% 5%	2154
	11th to 20th	Day	61% 6% 11% 14% 8% 1	2308
	21st to end	Day	59% 6% 12% 15% 6% 1	2340
May	1st to 10th	Day	55% 7% 16% 16% 5% 1	2456
	11th to 20th	Day	59% 9% 13% 14% 5%	2480
	21st to end	Day	55% 9% 17% 16% 3	2911
June	1st to 10th	Day	59% 10% 15% 11% 4 1	2700
	11th to 20th	Day	60% 10% 15% 10% 4	2700
	21st to end	Day	54% 10% 16% 13% 6% 1	2700
July	1st to 10th	Day	51% 10% 16% 13% 9% 1	2626
	11th to 20th	Day	45% 11% 20% 17% 6% 1	2619
	21st to end	Day	43% 13% 16% 19% 7% 1	2758
August	1st to 10th	Day	51% 13% 14% 14% 7% 1	2326
	11th to 20th	Day	45% 9% 17% 15% 11% 2	2298
	21st to end	Day	48% 10% 18% 19% 5%	2574
September	1st to 10th	Day	46% 11% 13% 19% 9% 2	2191
	11th to 20th	Day	55% 9% 10% 13% 12% 1	2030
	21st to end	Day	50% 7% 14% 19% 8% 2	1980
October	1st to 10th	Day	53% 9% 13% 12% 11% 2	1800
	11th to 20th	Day	62% 7% 13% 13% 4	1800
	21st to end	Day	60% 5% 11% 14% 9% 1	1834
November	1st to 10th	Day	69% 5% 12% 9% 4 1	1488
	11th to 20th	Day	68% 5% 8% 10% 8% 1	1520
	21st to end	Day	66% 5% 7% 14% 7% 1	1520
December	1st to 10th	Day	63% 5% 11% 13% 6% 2	1350
	11th to 20th	Day	73% 5% 7% 9% 4 1	1688
	21st to end	Day	77% 6% 6% 7% 4 1	2442
January	1st to 10th	Night	75% 6% 5% 10% 4 1	4726
	11th to 20th	Night	61% 4 9% 18% 6% 1	4740
	21st to end	Night	83% 3 4 8% 2 1	4894
February	1st to 10th	Night	70% 6% 8% 9% 6% 1	2397
	11th to 20th	Night	61% 6% 9% 13% 9% 1	2274
	21st to end	Night	64% 5% 7% 15% 7% 2	1924
March	1st to 10th	Night	67% 6% 7% 15% 4	2053
	11th to 20th	Night	69% 5% 10% 10% 5% 1	1980
	21st to end	Night	72% 5% 9% 11% 4	2178
April	1st to 10th	Night	64% 6% 10% 13% 6%	1803
	11th to 20th	Night	62% 5% 9% 17% 6% 1	1601
	21st to end	Night	61% 6% 8% 16% 8% 1	1620
May	1st to 10th	Night	51% 8% 16% 17% 7%	1504
	11th to 20th	Night	59% 7% 12% 18% 4 1	1416
	21st to end	Night	52% 9% 16% 19% 4	1362
June	1st to 10th	Night	59% 6% 16% 13% 4 2	1260
	11th to 20th	Night	59% 8% 16% 12% 4 1	1260
	21st to end	Night	52% 10% 14% 15% 7% 1	1260
July	1st to 10th	Night	46% 9% 17% 17% 10% 1	1225
	11th to 20th	Night	36% 10% 22% 22% 9% 1	1218
	21st to end	Night	40% 9% 17% 22% 10% 2	1319
August	1st to 10th	Night	50% 9% 15% 15% 10% 1	1585
	11th to 20th	Night	37% 7% 21% 19% 11% 4	1602
	21st to end	Night	45% 10% 17% 21% 6%	1782
September	1st to 10th	Night	40% 7% 14% 26% 10% 3	1768
	11th to 20th	Night	53% 7% 11% 13% 14% 2	1929
	21st to end	Night	49% 7% 14% 17% 10% 3	1980
October	1st to 10th	Night	52% 6% 11% 17% 13% 1	2160
	11th to 20th	Night	62% 5% 13% 13% 7%	2160
	21st to end	Night	62% 6% 9% 15% 8%	2517
November	1st to 10th	Night	70% 5% 9% 10% 5% 1	2590
	11th to 20th	Night	70% 6% 8% 8% 6% 2	2660
	21st to end	Night	65% 5% 10% 11% 7% 2	2660
December	1st to 10th	Night	65% 6% 9% 12% 7% 2	2826
	11th to 20th	Night	75% 5% 8% 6% 5% 1	3516
	21st to end	Night	77% 5% 7% 7% 4 1	5214

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	48% 8% 19% 15% 8% 2	180
	11th to 20th	Day	47% 7% 17% 20% 9% 1	180
	21st to end	Day	50% 5% 10% 17% 14% 3	350
February	1st to 10th	Day	43% 9% 15% 21% 10% 1	353
	11th to 20th	Day	39% 6% 15% 25% 13% 2	335
	21st to end	Day	33% 11% 16% 25% 11% 4	280
March	1st to 10th	Day	34% 6% 15% 20% 22% 3	388
	11th to 20th	Day	38% 7% 14% 22% 15% 4	420
	21st to end	Day	40% 5% 14% 22% 14% 4	462
April	1st to 10th	Day	39% 7% 17% 20% 13% 5%	420
	11th to 20th	Day	31% 3 15% 27% 15% 9%	412
	21st to end	Day	32% 8% 15% 26% 14% 4	420
May	1st to 10th	Day	23% 4 14% 26% 27% 5%	423
	11th to 20th	Day	26% 3 12% 24% 24% 11%	448
	21st to end	Day	19% 4 16% 29% 24% 8%	673
June	1st to 10th	Day	30% 4 13% 25% 23% 5%	630
	11th to 20th	Day	20% 5% 18% 32% 20% 5%	630
	21st to end	Day	20% 4 11% 27% 27% 11%	630
July	1st to 10th	Day	20% 4 9% 25% 33% 9%	621
	11th to 20th	Day	15% 2 12% 28% 31% 12%	618
	21st to end	Day	10% 2 9% 25% 38% 16%	666
August	1st to 10th	Day	17% 2 8% 20% 31% 21%	447
	11th to 20th	Day	12% 4 8% 19% 35% 21%	437
	21st to end	Day	20% 4 9% 26% 27% 13%	495
September	1st to 10th	Day	23% 3 10% 25% 30% 9%	450
	11th to 20th	Day	27% 3 11% 21% 24% 13%	450
	21st to end	Day	29% 2 14% 24% 21% 10%	450
October	1st to 10th	Day	29% 5% 9% 24% 23% 10%	450
	11th to 20th	Day	36% 7% 10% 20% 19% 8%	450
	21st to end	Day	38% 8% 14% 20% 13% 7%	421
November	1st to 10th	Day	43% 7% 14% 19% 15% 2	180
	11th to 20th	Day	38% 7% 14% 18% 15% 8%	180
	21st to end	Day	41% 8% 21% 12% 12% 6%	180
December	1st to 10th	Day	39% 7% 14% 20% 13% 6%	180
	11th to 20th	Day	41% 8% 17% 20% 11% 3	180
	21st to end	Day	47% 8% 12% 21% 11% 1	198
January	1st to 10th	Night	52% 8% 15% 16% 7% 1	850
	11th to 20th	Night	47% 7% 10% 21% 13% 1	850
	21st to end	Night	49% 5% 12% 17% 13% 3	915
February	1st to 10th	Night	46% 6% 17% 21% 9% 1	738
	11th to 20th	Night	38% 7% 15% 26% 13% 2	704
	21st to end	Night	41% 9% 16% 23% 8% 3	592
March	1st to 10th	Night	38% 9% 13% 17% 18% 5%	720
	11th to 20th	Night	42% 7% 16% 19% 12% 4	720
	21st to end	Night	42% 7% 13% 18% 16% 4	792
April	1st to 10th	Night	39% 6% 11% 21% 16% 6%	689
	11th to 20th	Night	36% 5% 10% 24% 19% 6%	533
	21st to end	Night	33% 5% 16% 23% 18% 4	540
May	1st to 10th	Night	25% 6% 9% 23% 27% 10%	424
	11th to 20th	Night	30% 3 6% 20% 29% 12%	354
	21st to end	Night	25% 1 11% 26% 28% 9%	389
June	1st to 10th	Night	28% 4 9% 25% 24% 11%	360
	11th to 20th	Night	25% 4 14% 28% 22% 7%	360
	21st to end	Night	20% 4 8% 26% 29% 14%	360
July	1st to 10th	Night	21% 3 6% 15% 37% 17%	350
	11th to 20th	Night	14% 4 7% 21% 33% 21%	348
	21st to end	Night	13% 2 7% 16% 33% 29%	394
August	1st to 10th	Night	22% 1 5% 13% 29% 30%	519
	11th to 20th	Night	15% 1 4 13% 37% 30%	534
	21st to end	Night	25% 1 10% 20% 31% 14%	594
September	1st to 10th	Night	19% 2 7% 22% 32% 18%	688
	11th to 20th	Night	28% 3 10% 14% 26% 19%	720
	21st to end	Night	32% 2 11% 22% 22% 11%	720
October	1st to 10th	Night	31% 4 9% 23% 23% 11%	720
	11th to 20th	Night	39% 3 9% 19% 21% 8%	720
	21st to end	Night	41% 5% 15% 23% 12% 4	792
November	1st to 10th	Night	46% 5% 17% 22% 9% 1	740
	11th to 20th	Night	44% 8% 14% 20% 10% 3	760
	21st to end	Night	43% 6% 14% 21% 11% 4	760
December	1st to 10th	Night	37% 6% 15% 24% 15% 3	838
	11th to 20th	Night	48% 7% 15% 20% 9% 1	850
	21st to end	Night	48% 7% 17% 22% 5% 1	935

Page generated at 2024-02-02 02:20:33. Version ac07

Copyright 2024 Attilla Danko