April saw El Nino conditions become more established in the tropical pacific. Though, NOAA called the El Nino in March, the Bureau of Meteorology did not declare an El Nino until early May by which time, the atmosphere as well as the ocean had started to get in sync.

Areas of South America, western Africa and southern Europe were unusually warm in April. Argentina had, in some places, its warmest April on record. Spain had its fourth warmest April on record. The US was generally warmer than average with Florida having its warmest April on record. Record heat was observed in the states of Central Asia. In Kazakhstan, in the first ten days of the month southerly winds blowing up from Iran brought an early summer and temperatures that reached 30degC. In Turkmenistan, 35degC. On April 23 Ashgabat a record temperature for April of 39.4degC was recorded. Towards the end of the month, Japan saw record daily temperatures for April .

Unusual cold was observed in western Australia and a limited area of northeast Africa.

Over Europe, a number of countries, including France, UK, Austria and Ireland, noted unusually sunny weather in April. In the UK it was the sunniest April on record (212 hours, 143% of 81-2010 average).

April saw the Second smallest Arctic sea ice extent for the month. At the other end of the Earth (or, at least, circling the other end of the Earth), Antarctic sea ice extent was the highest on record for the time of year.

Sweden – ice break up – http://www.smhi.se/nyhetsarkiv/ovanligt-tidig-islossning-i-haparanda-1.88054

In the US it was Generally drier than average in the northwest and wetter than average in the southeast. Kentucky, Louisiana and West Virginia were unusually wet. Kentucky received twice the monthly average of precipitation, causing widespread flooding. It was the second wettest April on record for the state.
In parts of China, April was unusually wet. In places two to three times the monthly average fell with the start of the month seeing particularly heavy rainfall. There were floods in the central parts of the country. In Henan and Hubei, more than 1.5 million people were affected by the floods and tens of thousands of hectares of farmland were flooded. In Australia, two east coast lows brought heavy rainfall to the coast of New South Wales. Rainfall was above average for parts of western Australia. In the north of the country by contrast, rainfall was below average. Tasmania was unusually dry, the fifth driest April on record. Southern India saw unusually high precipitation totals.

Flooding in Haiti in early April affected 9000 families. There was also flooding in Rwanda early in the month which affected around 685 households and crops. Rains caused flooding in Somalia in April but also improved water and pasture availability for pastoral communities.

Russian – http://www.meteoinfo.ru/climate/climat-tabl3/-2015-/11061–2015-
France – http://www.meteofrance.fr/actualites/24688982-un-mois-d-avril-chaud-ensoleille-et-plutot-sec
UK – http://www.metoffice.gov.uk/climate/uk/summaries/2015/april
Ireland – http://www.met.ie/climate/MonthlyWeather/clim-2015-Apr.pdf
New Zealand – http://www.niwa.co.nz/climate/nzcu/new-zealand-climate-update-191-may-2015/current-climate-%E2%80%93-april-2015 and http://www.niwa.co.nz/climate-summary-for-april-2015

Tropical storms
NW Pacific –Super Typhoon-5 MAYSAK 27 MAR-05 APR
Tropical Storm HAISHEN 03-06 APR
SW Pacific – Tropical Storm SOLO 10-12 APR
SW Indian – Tropical Storm HELLEN 01-01 APR
Cyclone-2 IKOLA 05-08 APR http://www.bom.gov.au/announcements/sevwx/wa/watc20150403.shtml
Cyclone-2 JOALANE 06-12 APR
Cyclone-4 QUANG 28 APR-01 MAY http://www.bom.gov.au/announcements/sevwx/wa/watc20150427.shtml